open-nomad/nomad/structs/structs.go

package structs

import (
	"bytes"
	"container/heap"
	"crypto/md5"
	"crypto/sha1"
	"crypto/sha256"
	"crypto/sha512"
	"encoding/base32"
	"encoding/base64"
	"encoding/hex"
	"errors"
	"fmt"
	"hash"
	"hash/crc32"
	"math"
	"net"
	"os"
	"path/filepath"
	"reflect"
	"regexp"
	"sort"
	"strconv"
	"strings"
	"time"

	"github.com/hashicorp/cronexpr"
	"github.com/hashicorp/go-msgpack/codec"
	"github.com/hashicorp/go-multierror"
	"github.com/hashicorp/go-version"
	"github.com/mitchellh/copystructure"
	"golang.org/x/crypto/blake2b"

	"github.com/hashicorp/nomad/acl"
	"github.com/hashicorp/nomad/command/agent/host"
	"github.com/hashicorp/nomad/command/agent/pprof"
	"github.com/hashicorp/nomad/helper"
	"github.com/hashicorp/nomad/helper/args"
	"github.com/hashicorp/nomad/helper/constraints/semver"
	"github.com/hashicorp/nomad/helper/uuid"
	"github.com/hashicorp/nomad/lib/kheap"
	psstructs "github.com/hashicorp/nomad/plugins/shared/structs"
)

var (
	// validPolicyName is used to validate a policy name
	validPolicyName = regexp.MustCompile("^[a-zA-Z0-9-]{1,128}$")

	// b32 is a lowercase base32 encoding for use in URL friendly service hashes
	b32 = base32.NewEncoding(strings.ToLower("abcdefghijklmnopqrstuvwxyz234567"))
)

type MessageType uint8

// note: new raft message types need to be added to the end of this
// list of contents
const (
	NodeRegisterRequestType                      MessageType = 0
	NodeDeregisterRequestType                    MessageType = 1
	NodeUpdateStatusRequestType                  MessageType = 2
	NodeUpdateDrainRequestType                   MessageType = 3
	JobRegisterRequestType                       MessageType = 4
	JobDeregisterRequestType                     MessageType = 5
	EvalUpdateRequestType                        MessageType = 6
	EvalDeleteRequestType                        MessageType = 7
	AllocUpdateRequestType                       MessageType = 8
	AllocClientUpdateRequestType                 MessageType = 9
	ReconcileJobSummariesRequestType             MessageType = 10
	VaultAccessorRegisterRequestType             MessageType = 11
	VaultAccessorDeregisterRequestType           MessageType = 12
	ApplyPlanResultsRequestType                  MessageType = 13
	DeploymentStatusUpdateRequestType            MessageType = 14
	DeploymentPromoteRequestType                 MessageType = 15
	DeploymentAllocHealthRequestType             MessageType = 16
	DeploymentDeleteRequestType                  MessageType = 17
	JobStabilityRequestType                      MessageType = 18
	ACLPolicyUpsertRequestType                   MessageType = 19
	ACLPolicyDeleteRequestType                   MessageType = 20
	ACLTokenUpsertRequestType                    MessageType = 21
	ACLTokenDeleteRequestType                    MessageType = 22
	ACLTokenBootstrapRequestType                 MessageType = 23
	AutopilotRequestType                         MessageType = 24
	UpsertNodeEventsType                         MessageType = 25
	JobBatchDeregisterRequestType                MessageType = 26
	AllocUpdateDesiredTransitionRequestType      MessageType = 27
	NodeUpdateEligibilityRequestType             MessageType = 28
	BatchNodeUpdateDrainRequestType              MessageType = 29
	SchedulerConfigRequestType                   MessageType = 30
	NodeBatchDeregisterRequestType               MessageType = 31
	ClusterMetadataRequestType                   MessageType = 32
	ServiceIdentityAccessorRegisterRequestType   MessageType = 33
	ServiceIdentityAccessorDeregisterRequestType MessageType = 34
	CSIVolumeRegisterRequestType                 MessageType = 35
	CSIVolumeDeregisterRequestType               MessageType = 36
	CSIVolumeClaimRequestType                    MessageType = 37
	ScalingEventRegisterRequestType              MessageType = 38
	CSIVolumeClaimBatchRequestType               MessageType = 39
	CSIPluginDeleteRequestType                   MessageType = 40
	EventSinkUpsertRequestType                   MessageType = 41
	EventSinkDeleteRequestType                   MessageType = 42
	BatchEventSinkUpdateProgressType             MessageType = 43

	// Namespace types were moved from enterprise and therefore start at 64
	NamespaceUpsertRequestType MessageType = 64
	NamespaceDeleteRequestType MessageType = 65
)

const (
	// IgnoreUnknownTypeFlag is set along with a MessageType
	// to indicate that the message type can be safely ignored
	// if it is not recognized. This is for future proofing, so
	// that new commands can be added in a way that won't cause
	// old servers to crash when the FSM attempts to process them.
	IgnoreUnknownTypeFlag MessageType = 128

	// MsgTypeTestSetup is used during testing when calling state store
	// methods directly that require an FSM MessageType
	MsgTypeTestSetup MessageType = IgnoreUnknownTypeFlag

	// ApiMajorVersion is returned as part of the Status.Version request.
	// It should be incremented anytime the APIs are changed in a way
	// that would break clients for sane client versioning.
	ApiMajorVersion = 1

	// ApiMinorVersion is returned as part of the Status.Version request.
	// It should be incremented anytime the APIs are changed to allow
	// for sane client versioning. Minor changes should be compatible
	// within the major version.
	ApiMinorVersion = 1

	ProtocolVersion = "protocol"
	APIMajorVersion = "api.major"
	APIMinorVersion = "api.minor"

	GetterModeAny  = "any"
	GetterModeFile = "file"
	GetterModeDir  = "dir"

	// maxPolicyDescriptionLength limits a policy description length
	maxPolicyDescriptionLength = 256

	// maxTokenNameLength limits a ACL token name length
	maxTokenNameLength = 256

	// ACLClientToken and ACLManagementToken are the only types of tokens
	ACLClientToken     = "client"
	ACLManagementToken = "management"

	// DefaultNamespace is the default namespace.
	DefaultNamespace            = "default"
	DefaultNamespaceDescription = "Default shared namespace"

	// AllNamespacesSentinel is the value used as a namespace RPC value
	// to indicate that endpoints must search in all namespaces
	AllNamespacesSentinel = "*"

	// maxNamespaceDescriptionLength limits a namespace description length
	maxNamespaceDescriptionLength = 256

	// JitterFraction is a the limit to the amount of jitter we apply
	// to a user specified MaxQueryTime. We divide the specified time by
	// the fraction. So 16 == 6.25% limit of jitter. This jitter is also
	// applied to RPCHoldTimeout.
	JitterFraction = 16

	// MaxRetainedNodeEvents is the maximum number of node events that will be
	// retained for a single node
	MaxRetainedNodeEvents = 10

	// MaxRetainedNodeScores is the number of top scoring nodes for which we
	// retain scoring metadata
	MaxRetainedNodeScores = 5

	// Normalized scorer name
	NormScorerName = "normalized-score"

	// MaxBlockingRPCQueryTime is used to bound the limit of a blocking query
	MaxBlockingRPCQueryTime = 300 * time.Second

	// DefaultBlockingRPCQueryTime is the amount of time we block waiting for a change
	// if no time is specified. Previously we would wait the MaxBlockingRPCQueryTime.
	DefaultBlockingRPCQueryTime = 300 * time.Second
)

var (
	// validNamespaceName is used to validate a namespace name
	validNamespaceName = regexp.MustCompile("^[a-zA-Z0-9-]{1,128}$")
)

// Context defines the scope in which a search for Nomad object operates, and
// is also used to query the matching index value for this context
type Context string

const (
	Allocs          Context = "allocs"
	Deployments     Context = "deployment"
	Evals           Context = "evals"
	Jobs            Context = "jobs"
	Nodes           Context = "nodes"
	Namespaces      Context = "namespaces"
	Quotas          Context = "quotas"
	Recommendations Context = "recommendations"
	ScalingPolicies Context = "scaling_policy"
	All             Context = "all"
	Plugins         Context = "plugins"
	Volumes         Context = "volumes"
)

// NamespacedID is a tuple of an ID and a namespace
type NamespacedID struct {
	ID        string
	Namespace string
}

// NewNamespacedID returns a new namespaced ID given the ID and namespace
func NewNamespacedID(id, ns string) NamespacedID {
	return NamespacedID{
		ID:        id,
		Namespace: ns,
	}
}

func (n NamespacedID) String() string {
	return fmt.Sprintf("<ns: %q, id: %q>", n.Namespace, n.ID)
}

// RPCInfo is used to describe common information about query
type RPCInfo interface {
	RequestRegion() string
	IsRead() bool
	AllowStaleRead() bool
	IsForwarded() bool
	SetForwarded()
	TimeToBlock() time.Duration
	// TimeToBlock sets how long this request can block. The requested time may not be possible,
	// so Callers should readback TimeToBlock. E.g. you cannot set time to block at all on WriteRequests
	// and it cannot exceed MaxBlockingRPCQueryTime
	SetTimeToBlock(t time.Duration)
}

// InternalRpcInfo allows adding internal RPC metadata to an RPC. This struct
// should NOT be replicated in the API package as it is internal only.
type InternalRpcInfo struct {
	// Forwarded marks whether the RPC has been forwarded.
	Forwarded bool
}

// IsForwarded returns whether the RPC is forwarded from another server.
func (i *InternalRpcInfo) IsForwarded() bool {
	return i.Forwarded
}

// SetForwarded marks that the RPC is being forwarded from another server.
func (i *InternalRpcInfo) SetForwarded() {
	i.Forwarded = true
}

// QueryOptions is used to specify various flags for read queries
type QueryOptions struct {
	// The target region for this query
	Region string

	// Namespace is the target namespace for the query.
	//
	// Since handlers do not have a default value set they should access
	// the Namespace via the RequestNamespace method.
	//
	// Requests accessing specific namespaced objects must check ACLs
	// against the namespace of the object, not the namespace in the
	// request.
	Namespace string

	// If set, wait until query exceeds given index. Must be provided
	// with MaxQueryTime.
	MinQueryIndex uint64

	// Provided with MinQueryIndex to wait for change.
	MaxQueryTime time.Duration

	// If set, any follower can service the request. Results
	// may be arbitrarily stale.
	AllowStale bool

	// If set, used as prefix for resource list searches
	Prefix string

	// AuthToken is secret portion of the ACL token used for the request
	AuthToken string

	InternalRpcInfo
}

// TimeToBlock returns MaxQueryTime adjusted for maximums and defaults
// it will return 0 if this is not a blocking query
func (q QueryOptions) TimeToBlock() time.Duration {
	if q.MinQueryIndex == 0 {
		return 0
	}
	if q.MaxQueryTime > MaxBlockingRPCQueryTime {
		return MaxBlockingRPCQueryTime
	} else if q.MaxQueryTime <= 0 {
		return DefaultBlockingRPCQueryTime
	}
	return q.MaxQueryTime
}

func (q QueryOptions) SetTimeToBlock(t time.Duration) {
	q.MaxQueryTime = t
}

func (q QueryOptions) RequestRegion() string {
	return q.Region
}

// RequestNamespace returns the request's namespace or the default namespace if
// no explicit namespace was sent.
//
// Requests accessing specific namespaced objects must check ACLs against the
// namespace of the object, not the namespace in the request.
func (q QueryOptions) RequestNamespace() string {
	if q.Namespace == "" {
		return DefaultNamespace
	}
	return q.Namespace
}

// QueryOption only applies to reads, so always true
func (q QueryOptions) IsRead() bool {
	return true
}

func (q QueryOptions) AllowStaleRead() bool {
	return q.AllowStale
}

// AgentPprofRequest is used to request a pprof report for a given node.
type AgentPprofRequest struct {
	// ReqType specifies the profile to use
	ReqType pprof.ReqType

	// Profile specifies the runtime/pprof profile to lookup and generate.
	Profile string

	// Seconds is the number of seconds to capture a profile
	Seconds int

	// Debug specifies if pprof profile should inclue debug output
	Debug int

	// GC specifies if the profile should call runtime.GC() before
	// running its profile. This is only used for "heap" profiles
	GC int

	// NodeID is the node we want to track the logs of
	NodeID string

	// ServerID is the server we want to track the logs of
	ServerID string

	QueryOptions
}

// AgentPprofResponse is used to return a generated pprof profile
type AgentPprofResponse struct {
	// ID of the agent that fulfilled the request
	AgentID string

	// Payload is the generated pprof profile
	Payload []byte

	// HTTPHeaders are a set of key value pairs to be applied as
	// HTTP headers for a specific runtime profile
	HTTPHeaders map[string]string
}

type WriteRequest struct {
	// The target region for this write
	Region string

	// Namespace is the target namespace for the write.
	//
	// Since RPC handlers do not have a default value set they should
	// access the Namespace via the RequestNamespace method.
	//
	// Requests accessing specific namespaced objects must check ACLs
	// against the namespace of the object, not the namespace in the
	// request.
	Namespace string

	// AuthToken is secret portion of the ACL token used for the request
	AuthToken string

	InternalRpcInfo
}

func (w WriteRequest) TimeToBlock() time.Duration {
	return 0
}

func (w WriteRequest) SetTimeToBlock(_ time.Duration) {
}

func (w WriteRequest) RequestRegion() string {
	// The target region for this request
	return w.Region
}

// RequestNamespace returns the request's namespace or the default namespace if
// no explicit namespace was sent.
//
// Requests accessing specific namespaced objects must check ACLs against the
// namespace of the object, not the namespace in the request.
func (w WriteRequest) RequestNamespace() string {
	if w.Namespace == "" {
		return DefaultNamespace
	}
	return w.Namespace
}

// WriteRequest only applies to writes, always false
func (w WriteRequest) IsRead() bool {
	return false
}

func (w WriteRequest) AllowStaleRead() bool {
	return false
}

// QueryMeta allows a query response to include potentially
// useful metadata about a query
type QueryMeta struct {
	// This is the index associated with the read
	Index uint64

	// If AllowStale is used, this is time elapsed since
	// last contact between the follower and leader. This
	// can be used to gauge staleness.
	LastContact time.Duration

	// Used to indicate if there is a known leader node
	KnownLeader bool
}

// WriteMeta allows a write response to include potentially
// useful metadata about the write
type WriteMeta struct {
	// This is the index associated with the write
	Index uint64
}

// NodeRegisterRequest is used for Node.Register endpoint
// to register a node as being a schedulable entity.
type NodeRegisterRequest struct {
	Node      *Node
	NodeEvent *NodeEvent
	WriteRequest
}

// NodeDeregisterRequest is used for Node.Deregister endpoint
// to deregister a node as being a schedulable entity.
type NodeDeregisterRequest struct {
	NodeID string
	WriteRequest
}

// NodeBatchDeregisterRequest is used for Node.BatchDeregister endpoint
// to deregister a batch of nodes from being schedulable entities.
type NodeBatchDeregisterRequest struct {
	NodeIDs []string
	WriteRequest
}

// NodeServerInfo is used to in NodeUpdateResponse to return Nomad server
// information used in RPC server lists.
type NodeServerInfo struct {
	// RPCAdvertiseAddr is the IP endpoint that a Nomad Server wishes to
	// be contacted at for RPCs.
	RPCAdvertiseAddr string

	// RpcMajorVersion is the major version number the Nomad Server
	// supports
	RPCMajorVersion int32

	// RpcMinorVersion is the minor version number the Nomad Server
	// supports
	RPCMinorVersion int32

	// Datacenter is the datacenter that a Nomad server belongs to
	Datacenter string
}

// NodeUpdateStatusRequest is used for Node.UpdateStatus endpoint
// to update the status of a node.
type NodeUpdateStatusRequest struct {
	NodeID    string
	Status    string
	NodeEvent *NodeEvent
	UpdatedAt int64
	WriteRequest
}

// NodeUpdateDrainRequest is used for updating the drain strategy
type NodeUpdateDrainRequest struct {
	NodeID        string
	DrainStrategy *DrainStrategy

	// COMPAT Remove in version 0.10
	// As part of Nomad 0.8 we have deprecated the drain boolean in favor of a
	// drain strategy but we need to handle the upgrade path where the Raft log
	// contains drain updates with just the drain boolean being manipulated.
	Drain bool

	// MarkEligible marks the node as eligible if removing the drain strategy.
	MarkEligible bool

	// NodeEvent is the event added to the node
	NodeEvent *NodeEvent

	// UpdatedAt represents server time of receiving request
	UpdatedAt int64

	WriteRequest
}

// BatchNodeUpdateDrainRequest is used for updating the drain strategy for a
// batch of nodes
type BatchNodeUpdateDrainRequest struct {
	// Updates is a mapping of nodes to their updated drain strategy
	Updates map[string]*DrainUpdate

	// NodeEvents is a mapping of the node to the event to add to the node
	NodeEvents map[string]*NodeEvent

	// UpdatedAt represents server time of receiving request
	UpdatedAt int64

	WriteRequest
}

// DrainUpdate is used to update the drain of a node
type DrainUpdate struct {
	// DrainStrategy is the new strategy for the node
	DrainStrategy *DrainStrategy

	// MarkEligible marks the node as eligible if removing the drain strategy.
	MarkEligible bool
}

// NodeUpdateEligibilityRequest is used for updating the scheduling	eligibility
type NodeUpdateEligibilityRequest struct {
	NodeID      string
	Eligibility string

	// NodeEvent is the event added to the node
	NodeEvent *NodeEvent

	// UpdatedAt represents server time of receiving request
	UpdatedAt int64

	WriteRequest
}

// NodeEvaluateRequest is used to re-evaluate the node
type NodeEvaluateRequest struct {
	NodeID string
	WriteRequest
}

// NodeSpecificRequest is used when we just need to specify a target node
type NodeSpecificRequest struct {
	NodeID   string
	SecretID string
	QueryOptions
}

// SearchResponse is used to return matches and information about whether
// the match list is truncated specific to each type of context.
type SearchResponse struct {
	// Map of context types to ids which match a specified prefix
	Matches map[Context][]string

	// Truncations indicates whether the matches for a particular context have
	// been truncated
	Truncations map[Context]bool

	QueryMeta
}

// SearchRequest is used to parameterize a request, and returns a
// list of matches made up of jobs, allocations, evaluations, and/or nodes,
// along with whether or not the information returned is truncated.
type SearchRequest struct {
	// Prefix is what ids are matched to. I.e, if the given prefix were
	// "a", potential matches might be "abcd" or "aabb"
	Prefix string

	// Context is the type that can be matched against. A context can be a job,
	// node, evaluation, allocation, or empty (indicated every context should be
	// matched)
	Context Context

	QueryOptions
}

// JobRegisterRequest is used for Job.Register endpoint
// to register a job as being a schedulable entity.
type JobRegisterRequest struct {
	Job *Job

	// If EnforceIndex is set then the job will only be registered if the passed
	// JobModifyIndex matches the current Jobs index. If the index is zero, the
	// register only occurs if the job is new.
	EnforceIndex   bool
	JobModifyIndex uint64

	// PreserveCounts indicates that during job update, existing task group
	// counts should be preserved, over those specified in the new job spec
	// PreserveCounts is ignored for newly created jobs.
	PreserveCounts bool

	// PolicyOverride is set when the user is attempting to override any policies
	PolicyOverride bool

	// Eval is the evaluation that is associated with the job registration
	Eval *Evaluation

	WriteRequest
}

// JobDeregisterRequest is used for Job.Deregister endpoint
// to deregister a job as being a schedulable entity.
type JobDeregisterRequest struct {
	JobID string

	// Purge controls whether the deregister purges the job from the system or
	// whether the job is just marked as stopped and will be removed by the
	// garbage collector
	Purge bool

	// Global controls whether all regions of a multi-region job are
	// deregistered. It is ignored for single-region jobs.
	Global bool

	// Eval is the evaluation to create that's associated with job deregister
	Eval *Evaluation

	WriteRequest
}

// JobBatchDeregisterRequest is used to batch deregister jobs and upsert
// evaluations.
type JobBatchDeregisterRequest struct {
	// Jobs is the set of jobs to deregister
	Jobs map[NamespacedID]*JobDeregisterOptions

	// Evals is the set of evaluations to create.
	Evals []*Evaluation

	WriteRequest
}

// JobDeregisterOptions configures how a job is deregistered.
type JobDeregisterOptions struct {
	// Purge controls whether the deregister purges the job from the system or
	// whether the job is just marked as stopped and will be removed by the
	// garbage collector
	Purge bool
}

// JobEvaluateRequest is used when we just need to re-evaluate a target job
type JobEvaluateRequest struct {
	JobID       string
	EvalOptions EvalOptions
	WriteRequest
}

// EvalOptions is used to encapsulate options when forcing a job evaluation
type EvalOptions struct {
	ForceReschedule bool
}

// JobSpecificRequest is used when we just need to specify a target job
type JobSpecificRequest struct {
	JobID string
	All   bool
	QueryOptions
}

// JobListRequest is used to parameterize a list request
type JobListRequest struct {
	QueryOptions
}

// JobPlanRequest is used for the Job.Plan endpoint to trigger a dry-run
// evaluation of the Job.
type JobPlanRequest struct {
	Job  *Job
	Diff bool // Toggles an annotated diff
	// PolicyOverride is set when the user is attempting to override any policies
	PolicyOverride bool
	WriteRequest
}

// JobScaleRequest is used for the Job.Scale endpoint to scale one of the
// scaling targets in a job
type JobScaleRequest struct {
	JobID   string
	Target  map[string]string
	Count   *int64
	Message string
	Error   bool
	Meta    map[string]interface{}
	// PolicyOverride is set when the user is attempting to override any policies
	PolicyOverride bool
	WriteRequest
}

// Validate is used to validate the arguments in the request
func (r *JobScaleRequest) Validate() error {
	namespace := r.Target[ScalingTargetNamespace]
	if namespace != "" && namespace != r.RequestNamespace() {
		return NewErrRPCCoded(400, "namespace in payload did not match header")
	}

	jobID := r.Target[ScalingTargetJob]
	if jobID != "" && jobID != r.JobID {
		return fmt.Errorf("job ID in payload did not match URL")
	}

	groupName := r.Target[ScalingTargetGroup]
	if groupName == "" {
		return NewErrRPCCoded(400, "missing task group name for scaling action")
	}

	if r.Count != nil {
		if *r.Count < 0 {
			return NewErrRPCCoded(400, "scaling action count can't be negative")
		}

		if r.Error {
			return NewErrRPCCoded(400, "scaling action should not contain count if error is true")
		}

		truncCount := int(*r.Count)
		if int64(truncCount) != *r.Count {
			return NewErrRPCCoded(400,
				fmt.Sprintf("new scaling count is too large for TaskGroup.Count (int): %v", r.Count))
		}
	}

	return nil
}

// JobSummaryRequest is used when we just need to get a specific job summary
type JobSummaryRequest struct {
	JobID string
	QueryOptions
}

// JobScaleStatusRequest is used to get the scale status for a job
type JobScaleStatusRequest struct {
	JobID string
	QueryOptions
}

// JobDispatchRequest is used to dispatch a job based on a parameterized job
type JobDispatchRequest struct {
	JobID   string
	Payload []byte
	Meta    map[string]string
	WriteRequest
}

// JobValidateRequest is used to validate a job
type JobValidateRequest struct {
	Job *Job
	WriteRequest
}

// JobRevertRequest is used to revert a job to a prior version.
type JobRevertRequest struct {
	// JobID is the ID of the job  being reverted
	JobID string

	// JobVersion the version to revert to.
	JobVersion uint64

	// EnforcePriorVersion if set will enforce that the job is at the given
	// version before reverting.
	EnforcePriorVersion *uint64

	// ConsulToken is the Consul token that proves the submitter of the job revert
	// has access to the Service Identity policies associated with the job's
	// Consul Connect enabled services. This field is only used to transfer the
	// token and is not stored after the Job revert.
	ConsulToken string

	// VaultToken is the Vault token that proves the submitter of the job revert
	// has access to any Vault policies specified in the targeted job version. This
	// field is only used to transfer the token and is not stored after the Job
	// revert.
	VaultToken string

	WriteRequest
}

// JobStabilityRequest is used to marked a job as stable.
type JobStabilityRequest struct {
	// Job to set the stability on
	JobID      string
	JobVersion uint64

	// Set the stability
	Stable bool
	WriteRequest
}

// JobStabilityResponse is the response when marking a job as stable.
type JobStabilityResponse struct {
	WriteMeta
}

// NodeListRequest is used to parameterize a list request
type NodeListRequest struct {
	QueryOptions

	Fields *NodeStubFields
}

// EvalUpdateRequest is used for upserting evaluations.
type EvalUpdateRequest struct {
	Evals     []*Evaluation
	EvalToken string
	WriteRequest
}

// EvalDeleteRequest is used for deleting an evaluation.
type EvalDeleteRequest struct {
	Evals  []string
	Allocs []string
	WriteRequest
}

// EvalSpecificRequest is used when we just need to specify a target evaluation
type EvalSpecificRequest struct {
	EvalID string
	QueryOptions
}

// EvalAckRequest is used to Ack/Nack a specific evaluation
type EvalAckRequest struct {
	EvalID string
	Token  string
	WriteRequest
}

// EvalDequeueRequest is used when we want to dequeue an evaluation
type EvalDequeueRequest struct {
	Schedulers       []string
	Timeout          time.Duration
	SchedulerVersion uint16
	WriteRequest
}

// EvalListRequest is used to list the evaluations
type EvalListRequest struct {
	QueryOptions
}

// PlanRequest is used to submit an allocation plan to the leader
type PlanRequest struct {
	Plan *Plan
	WriteRequest
}

// ApplyPlanResultsRequest is used by the planner to apply a Raft transaction
// committing the result of a plan.
type ApplyPlanResultsRequest struct {
	// AllocUpdateRequest holds the allocation updates to be made by the
	// scheduler.
	AllocUpdateRequest

	// Deployment is the deployment created or updated as a result of a
	// scheduling event.
	Deployment *Deployment

	// DeploymentUpdates is a set of status updates to apply to the given
	// deployments. This allows the scheduler to cancel any unneeded deployment
	// because the job is stopped or the update block is removed.
	DeploymentUpdates []*DeploymentStatusUpdate

	// EvalID is the eval ID of the plan being applied. The modify index of the
	// evaluation is updated as part of applying the plan to ensure that subsequent
	// scheduling events for the same job will wait for the index that last produced
	// state changes. This is necessary for blocked evaluations since they can be
	// processed many times, potentially making state updates, without the state of
	// the evaluation itself being updated.
	EvalID string

	// COMPAT 0.11
	// NodePreemptions is a slice of allocations from other lower priority jobs
	// that are preempted. Preempted allocations are marked as evicted.
	// Deprecated: Replaced with AllocsPreempted which contains only the diff
	NodePreemptions []*Allocation

	// AllocsPreempted is a slice of allocation diffs from other lower priority jobs
	// that are preempted. Preempted allocations are marked as evicted.
	AllocsPreempted []*AllocationDiff

	// PreemptionEvals is a slice of follow up evals for jobs whose allocations
	// have been preempted to place allocs in this plan
	PreemptionEvals []*Evaluation
}

// AllocUpdateRequest is used to submit changes to allocations, either
// to cause evictions or to assign new allocations. Both can be done
// within a single transaction
type AllocUpdateRequest struct {
	// COMPAT 0.11
	// Alloc is the list of new allocations to assign
	// Deprecated: Replaced with two separate slices, one containing stopped allocations
	// and another containing updated allocations
	Alloc []*Allocation

	// Allocations to stop. Contains only the diff, not the entire allocation
	AllocsStopped []*AllocationDiff

	// New or updated allocations
	AllocsUpdated []*Allocation

	// Evals is the list of new evaluations to create
	// Evals are valid only when used in the Raft RPC
	Evals []*Evaluation

	// Job is the shared parent job of the allocations.
	// It is pulled out since it is common to reduce payload size.
	Job *Job

	WriteRequest
}

// AllocUpdateDesiredTransitionRequest is used to submit changes to allocations
// desired transition state.
type AllocUpdateDesiredTransitionRequest struct {
	// Allocs is the mapping of allocation ids to their desired state
	// transition
	Allocs map[string]*DesiredTransition

	// Evals is the set of evaluations to create
	Evals []*Evaluation

	WriteRequest
}

// AllocStopRequest is used to stop and reschedule a running Allocation.
type AllocStopRequest struct {
	AllocID string

	WriteRequest
}

// AllocStopResponse is the response to an `AllocStopRequest`
type AllocStopResponse struct {
	// EvalID is the id of the follow up evalution for the rescheduled alloc.
	EvalID string

	WriteMeta
}

// AllocListRequest is used to request a list of allocations
type AllocListRequest struct {
	QueryOptions

	Fields *AllocStubFields
}

// AllocSpecificRequest is used to query a specific allocation
type AllocSpecificRequest struct {
	AllocID string
	QueryOptions
}

// AllocSignalRequest is used to signal a specific allocation
type AllocSignalRequest struct {
	AllocID string
	Task    string
	Signal  string
	QueryOptions
}

// AllocsGetRequest is used to query a set of allocations
type AllocsGetRequest struct {
	AllocIDs []string
	QueryOptions
}

// AllocRestartRequest is used to restart a specific allocations tasks.
type AllocRestartRequest struct {
	AllocID  string
	TaskName string

	QueryOptions
}

// PeriodicForceRequest is used to force a specific periodic job.
type PeriodicForceRequest struct {
	JobID string
	WriteRequest
}

// ServerMembersResponse has the list of servers in a cluster
type ServerMembersResponse struct {
	ServerName   string
	ServerRegion string
	ServerDC     string
	Members      []*ServerMember
}

// ServerMember holds information about a Nomad server agent in a cluster
type ServerMember struct {
	Name        string
	Addr        net.IP
	Port        uint16
	Tags        map[string]string
	Status      string
	ProtocolMin uint8
	ProtocolMax uint8
	ProtocolCur uint8
	DelegateMin uint8
	DelegateMax uint8
	DelegateCur uint8
}

// ClusterMetadata is used to store per-cluster metadata.
type ClusterMetadata struct {
	ClusterID  string
	CreateTime int64
}

// DeriveVaultTokenRequest is used to request wrapped Vault tokens for the
// following tasks in the given allocation
type DeriveVaultTokenRequest struct {
	NodeID   string
	SecretID string
	AllocID  string
	Tasks    []string
	QueryOptions
}

// VaultAccessorsRequest is used to operate on a set of Vault accessors
type VaultAccessorsRequest struct {
	Accessors []*VaultAccessor
}

// VaultAccessor is a reference to a created Vault token on behalf of
// an allocation's task.
type VaultAccessor struct {
	AllocID     string
	Task        string
	NodeID      string
	Accessor    string
	CreationTTL int

	// Raft Indexes
	CreateIndex uint64
}

// DeriveVaultTokenResponse returns the wrapped tokens for each requested task
type DeriveVaultTokenResponse struct {
	// Tasks is a mapping between the task name and the wrapped token
	Tasks map[string]string

	// Error stores any error that occurred. Errors are stored here so we can
	// communicate whether it is retryable
	Error *RecoverableError

	QueryMeta
}

// GenericRequest is used to request where no
// specific information is needed.
type GenericRequest struct {
	QueryOptions
}

// DeploymentListRequest is used to list the deployments
type DeploymentListRequest struct {
	QueryOptions
}

// DeploymentDeleteRequest is used for deleting deployments.
type DeploymentDeleteRequest struct {
	Deployments []string
	WriteRequest
}

// DeploymentStatusUpdateRequest is used to update the status of a deployment as
// well as optionally creating an evaluation atomically.
type DeploymentStatusUpdateRequest struct {
	// Eval, if set, is used to create an evaluation at the same time as
	// updating the status of a deployment.
	Eval *Evaluation

	// DeploymentUpdate is a status update to apply to the given
	// deployment.
	DeploymentUpdate *DeploymentStatusUpdate

	// Job is used to optionally upsert a job. This is used when setting the
	// allocation health results in a deployment failure and the deployment
	// auto-reverts to the latest stable job.
	Job *Job
}

// DeploymentAllocHealthRequest is used to set the health of a set of
// allocations as part of a deployment.
type DeploymentAllocHealthRequest struct {
	DeploymentID string

	// Marks these allocations as healthy, allow further allocations
	// to be rolled.
	HealthyAllocationIDs []string

	// Any unhealthy allocations fail the deployment
	UnhealthyAllocationIDs []string

	WriteRequest
}

// ApplyDeploymentAllocHealthRequest is used to apply an alloc health request via Raft
type ApplyDeploymentAllocHealthRequest struct {
	DeploymentAllocHealthRequest

	// Timestamp is the timestamp to use when setting the allocations health.
	Timestamp time.Time

	// An optional field to update the status of a deployment
	DeploymentUpdate *DeploymentStatusUpdate

	// Job is used to optionally upsert a job. This is used when setting the
	// allocation health results in a deployment failure and the deployment
	// auto-reverts to the latest stable job.
	Job *Job

	// An optional evaluation to create after promoting the canaries
	Eval *Evaluation
}

// DeploymentPromoteRequest is used to promote task groups in a deployment
type DeploymentPromoteRequest struct {
	DeploymentID string

	// All is to promote all task groups
	All bool

	// Groups is used to set the promotion status per task group
	Groups []string

	WriteRequest
}

// ApplyDeploymentPromoteRequest is used to apply a promotion request via Raft
type ApplyDeploymentPromoteRequest struct {
	DeploymentPromoteRequest

	// An optional evaluation to create after promoting the canaries
	Eval *Evaluation
}

// DeploymentPauseRequest is used to pause a deployment
type DeploymentPauseRequest struct {
	DeploymentID string

	// Pause sets the pause status
	Pause bool

	WriteRequest
}

// DeploymentRunRequest is used to remotely start a pending deployment.
// Used only for multiregion deployments.
type DeploymentRunRequest struct {
	DeploymentID string

	WriteRequest
}

// DeploymentUnblockRequest is used to remotely unblock a deployment.
// Used only for multiregion deployments.
type DeploymentUnblockRequest struct {
	DeploymentID string

	WriteRequest
}

// DeploymentCancelRequest is used to remotely cancel a deployment.
// Used only for multiregion deployments.
type DeploymentCancelRequest struct {
	DeploymentID string

	WriteRequest
}

// DeploymentSpecificRequest is used to make a request specific to a particular
// deployment
type DeploymentSpecificRequest struct {
	DeploymentID string
	QueryOptions
}

// DeploymentFailRequest is used to fail a particular deployment
type DeploymentFailRequest struct {
	DeploymentID string
	WriteRequest
}

// ScalingPolicySpecificRequest is used when we just need to specify a target scaling policy
type ScalingPolicySpecificRequest struct {
	ID string
	QueryOptions
}

// SingleScalingPolicyResponse is used to return a single job
type SingleScalingPolicyResponse struct {
	Policy *ScalingPolicy
	QueryMeta
}

// ScalingPolicyListRequest is used to parameterize a scaling policy list request
type ScalingPolicyListRequest struct {
	Job  string
	Type string
	QueryOptions
}

// ScalingPolicyListResponse is used for a list request
type ScalingPolicyListResponse struct {
	Policies []*ScalingPolicyListStub
	QueryMeta
}

// SingleDeploymentResponse is used to respond with a single deployment
type SingleDeploymentResponse struct {
	Deployment *Deployment
	QueryMeta
}

// GenericResponse is used to respond to a request where no
// specific response information is needed.
type GenericResponse struct {
	WriteMeta
}

// VersionResponse is used for the Status.Version response
type VersionResponse struct {
	Build    string
	Versions map[string]int
	QueryMeta
}

// JobRegisterResponse is used to respond to a job registration
type JobRegisterResponse struct {
	EvalID          string
	EvalCreateIndex uint64
	JobModifyIndex  uint64

	// Warnings contains any warnings about the given job. These may include
	// deprecation warnings.
	Warnings string

	QueryMeta
}

// JobDeregisterResponse is used to respond to a job deregistration
type JobDeregisterResponse struct {
	EvalID          string
	EvalCreateIndex uint64
	JobModifyIndex  uint64
	VolumeEvalID    string
	VolumeEvalIndex uint64
	QueryMeta
}

// JobBatchDeregisterResponse is used to respond to a batch job deregistration
type JobBatchDeregisterResponse struct {
	// JobEvals maps the job to its created evaluation
	JobEvals map[NamespacedID]string
	QueryMeta
}

// JobValidateResponse is the response from validate request
type JobValidateResponse struct {
	// DriverConfigValidated indicates whether the agent validated the driver
	// config
	DriverConfigValidated bool

	// ValidationErrors is a list of validation errors
	ValidationErrors []string

	// Error is a string version of any error that may have occurred
	Error string

	// Warnings contains any warnings about the given job. These may include
	// deprecation warnings.
	Warnings string
}

// NodeUpdateResponse is used to respond to a node update
type NodeUpdateResponse struct {
	HeartbeatTTL    time.Duration
	EvalIDs         []string
	EvalCreateIndex uint64
	NodeModifyIndex uint64

	// Features informs clients what enterprise features are allowed
	Features uint64

	// LeaderRPCAddr is the RPC address of the current Raft Leader.  If
	// empty, the current Nomad Server is in the minority of a partition.
	LeaderRPCAddr string

	// NumNodes is the number of Nomad nodes attached to this quorum of
	// Nomad Servers at the time of the response.  This value can
	// fluctuate based on the health of the cluster between heartbeats.
	NumNodes int32

	// Servers is the full list of known Nomad servers in the local
	// region.
	Servers []*NodeServerInfo

	QueryMeta
}

// NodeDrainUpdateResponse is used to respond to a node drain update
type NodeDrainUpdateResponse struct {
	NodeModifyIndex uint64
	EvalIDs         []string
	EvalCreateIndex uint64
	WriteMeta
}

// NodeEligibilityUpdateResponse is used to respond to a node eligibility update
type NodeEligibilityUpdateResponse struct {
	NodeModifyIndex uint64
	EvalIDs         []string
	EvalCreateIndex uint64
	WriteMeta
}

// NodeAllocsResponse is used to return allocs for a single node
type NodeAllocsResponse struct {
	Allocs []*Allocation
	QueryMeta
}

// NodeClientAllocsResponse is used to return allocs meta data for a single node
type NodeClientAllocsResponse struct {
	Allocs map[string]uint64

	// MigrateTokens are used when ACLs are enabled to allow cross node,
	// authenticated access to sticky volumes
	MigrateTokens map[string]string

	QueryMeta
}

// SingleNodeResponse is used to return a single node
type SingleNodeResponse struct {
	Node *Node
	QueryMeta
}

// NodeListResponse is used for a list request
type NodeListResponse struct {
	Nodes []*NodeListStub
	QueryMeta
}

// SingleJobResponse is used to return a single job
type SingleJobResponse struct {
	Job *Job
	QueryMeta
}

// JobSummaryResponse is used to return a single job summary
type JobSummaryResponse struct {
	JobSummary *JobSummary
	QueryMeta
}

// JobScaleStatusResponse is used to return the scale status for a job
type JobScaleStatusResponse struct {
	JobScaleStatus *JobScaleStatus
	QueryMeta
}

type JobScaleStatus struct {
	JobID          string
	Namespace      string
	JobCreateIndex uint64
	JobModifyIndex uint64
	JobStopped     bool
	TaskGroups     map[string]*TaskGroupScaleStatus
}

// TaskGroupScaleStatus is used to return the scale status for a given task group
type TaskGroupScaleStatus struct {
	Desired   int
	Placed    int
	Running   int
	Healthy   int
	Unhealthy int
	Events    []*ScalingEvent
}

type JobDispatchResponse struct {
	DispatchedJobID string
	EvalID          string
	EvalCreateIndex uint64
	JobCreateIndex  uint64
	WriteMeta
}

// JobListResponse is used for a list request
type JobListResponse struct {
	Jobs []*JobListStub
	QueryMeta
}

// JobVersionsRequest is used to get a jobs versions
type JobVersionsRequest struct {
	JobID string
	Diffs bool
	QueryOptions
}

// JobVersionsResponse is used for a job get versions request
type JobVersionsResponse struct {
	Versions []*Job
	Diffs    []*JobDiff
	QueryMeta
}

// JobPlanResponse is used to respond to a job plan request
type JobPlanResponse struct {
	// Annotations stores annotations explaining decisions the scheduler made.
	Annotations *PlanAnnotations

	// FailedTGAllocs is the placement failures per task group.
	FailedTGAllocs map[string]*AllocMetric

	// JobModifyIndex is the modification index of the job. The value can be
	// used when running `nomad run` to ensure that the Job wasn’t modified
	// since the last plan. If the job is being created, the value is zero.
	JobModifyIndex uint64

	// CreatedEvals is the set of evaluations created by the scheduler. The
	// reasons for this can be rolling-updates or blocked evals.
	CreatedEvals []*Evaluation

	// Diff contains the diff of the job and annotations on whether the change
	// causes an in-place update or create/destroy
	Diff *JobDiff

	// NextPeriodicLaunch is the time duration till the job would be launched if
	// submitted.
	NextPeriodicLaunch time.Time

	// Warnings contains any warnings about the given job. These may include
	// deprecation warnings.
	Warnings string

	WriteMeta
}

// SingleAllocResponse is used to return a single allocation
type SingleAllocResponse struct {
	Alloc *Allocation
	QueryMeta
}

// AllocsGetResponse is used to return a set of allocations
type AllocsGetResponse struct {
	Allocs []*Allocation
	QueryMeta
}

// JobAllocationsResponse is used to return the allocations for a job
type JobAllocationsResponse struct {
	Allocations []*AllocListStub
	QueryMeta
}

// JobEvaluationsResponse is used to return the evaluations for a job
type JobEvaluationsResponse struct {
	Evaluations []*Evaluation
	QueryMeta
}

// SingleEvalResponse is used to return a single evaluation
type SingleEvalResponse struct {
	Eval *Evaluation
	QueryMeta
}

// EvalDequeueResponse is used to return from a dequeue
type EvalDequeueResponse struct {
	Eval  *Evaluation
	Token string

	// WaitIndex is the Raft index the worker should wait until invoking the
	// scheduler.
	WaitIndex uint64

	QueryMeta
}

// GetWaitIndex is used to retrieve the Raft index in which state should be at
// or beyond before invoking the scheduler.
func (e *EvalDequeueResponse) GetWaitIndex() uint64 {
	// Prefer the wait index sent. This will be populated on all responses from
	// 0.7.0 and above
	if e.WaitIndex != 0 {
		return e.WaitIndex
	} else if e.Eval != nil {
		return e.Eval.ModifyIndex
	}

	// This should never happen
	return 1
}

// PlanResponse is used to return from a PlanRequest
type PlanResponse struct {
	Result *PlanResult
	WriteMeta
}

// AllocListResponse is used for a list request
type AllocListResponse struct {
	Allocations []*AllocListStub
	QueryMeta
}

// DeploymentListResponse is used for a list request
type DeploymentListResponse struct {
	Deployments []*Deployment
	QueryMeta
}

// EvalListResponse is used for a list request
type EvalListResponse struct {
	Evaluations []*Evaluation
	QueryMeta
}

// EvalAllocationsResponse is used to return the allocations for an evaluation
type EvalAllocationsResponse struct {
	Allocations []*AllocListStub
	QueryMeta
}

// PeriodicForceResponse is used to respond to a periodic job force launch
type PeriodicForceResponse struct {
	EvalID          string
	EvalCreateIndex uint64
	WriteMeta
}

// DeploymentUpdateResponse is used to respond to a deployment change. The
// response will include the modify index of the deployment as well as details
// of any triggered evaluation.
type DeploymentUpdateResponse struct {
	EvalID                string
	EvalCreateIndex       uint64
	DeploymentModifyIndex uint64

	// RevertedJobVersion is the version the job was reverted to. If unset, the
	// job wasn't reverted
	RevertedJobVersion *uint64

	WriteMeta
}

// NodeConnQueryResponse is used to respond to a query of whether a server has
// a connection to a specific Node
type NodeConnQueryResponse struct {
	// Connected indicates whether a connection to the Client exists
	Connected bool

	// Established marks the time at which the connection was established
	Established time.Time

	QueryMeta
}

// HostDataRequest is used by /agent/host to retrieve data about the agent's host system. If
// ServerID or NodeID is specified, the request is forwarded to the remote agent
type HostDataRequest struct {
	ServerID string
	NodeID   string
	QueryOptions
}

// HostDataResponse contains the HostData content
type HostDataResponse struct {
	AgentID  string
	HostData *host.HostData
}

// EmitNodeEventsRequest is a request to update the node events source
// with a new client-side event
type EmitNodeEventsRequest struct {
	// NodeEvents are a map where the key is a node id, and value is a list of
	// events for that node
	NodeEvents map[string][]*NodeEvent

	WriteRequest
}

// EmitNodeEventsResponse is a response to the client about the status of
// the node event source update.
type EmitNodeEventsResponse struct {
	WriteMeta
}

const (
	NodeEventSubsystemDrain     = "Drain"
	NodeEventSubsystemDriver    = "Driver"
	NodeEventSubsystemHeartbeat = "Heartbeat"
	NodeEventSubsystemCluster   = "Cluster"
	NodeEventSubsystemStorage   = "Storage"
)

// NodeEvent is a single unit representing a node’s state change
type NodeEvent struct {
	Message     string
	Subsystem   string
	Details     map[string]string
	Timestamp   time.Time
	CreateIndex uint64
}

func (ne *NodeEvent) String() string {
	var details []string
	for k, v := range ne.Details {
		details = append(details, fmt.Sprintf("%s: %s", k, v))
	}

	return fmt.Sprintf("Message: %s, Subsystem: %s, Details: %s, Timestamp: %s", ne.Message, ne.Subsystem, strings.Join(details, ","), ne.Timestamp.String())
}

func (ne *NodeEvent) Copy() *NodeEvent {
	c := new(NodeEvent)
	*c = *ne
	c.Details = helper.CopyMapStringString(ne.Details)
	return c
}

// NewNodeEvent generates a new node event storing the current time as the
// timestamp
func NewNodeEvent() *NodeEvent {
	return &NodeEvent{Timestamp: time.Now()}
}

// SetMessage is used to set the message on the node event
func (ne *NodeEvent) SetMessage(msg string) *NodeEvent {
	ne.Message = msg
	return ne
}

// SetSubsystem is used to set the subsystem on the node event
func (ne *NodeEvent) SetSubsystem(sys string) *NodeEvent {
	ne.Subsystem = sys
	return ne
}

// SetTimestamp is used to set the timestamp on the node event
func (ne *NodeEvent) SetTimestamp(ts time.Time) *NodeEvent {
	ne.Timestamp = ts
	return ne
}

// AddDetail is used to add a detail to the node event
func (ne *NodeEvent) AddDetail(k, v string) *NodeEvent {
	if ne.Details == nil {
		ne.Details = make(map[string]string, 1)
	}
	ne.Details[k] = v
	return ne
}

const (
	NodeStatusInit  = "initializing"
	NodeStatusReady = "ready"
	NodeStatusDown  = "down"
)

// ShouldDrainNode checks if a given node status should trigger an
// evaluation. Some states don't require any further action.
func ShouldDrainNode(status string) bool {
	switch status {
	case NodeStatusInit, NodeStatusReady:
		return false
	case NodeStatusDown:
		return true
	default:
		panic(fmt.Sprintf("unhandled node status %s", status))
	}
}

// ValidNodeStatus is used to check if a node status is valid
func ValidNodeStatus(status string) bool {
	switch status {
	case NodeStatusInit, NodeStatusReady, NodeStatusDown:
		return true
	default:
		return false
	}
}

const (
	// NodeSchedulingEligible and Ineligible marks the node as eligible or not,
	// respectively, for receiving allocations. This is orthoginal to the node
	// status being ready.
	NodeSchedulingEligible   = "eligible"
	NodeSchedulingIneligible = "ineligible"
)

// DrainSpec describes a Node's desired drain behavior.
type DrainSpec struct {
	// Deadline is the duration after StartTime when the remaining
	// allocations on a draining Node should be told to stop.
	Deadline time.Duration

	// IgnoreSystemJobs allows systems jobs to remain on the node even though it
	// has been marked for draining.
	IgnoreSystemJobs bool
}

// DrainStrategy describes a Node's drain behavior.
type DrainStrategy struct {
	// DrainSpec is the user declared drain specification
	DrainSpec

	// ForceDeadline is the deadline time for the drain after which drains will
	// be forced
	ForceDeadline time.Time

	// StartedAt is the time the drain process started
	StartedAt time.Time
}

func (d *DrainStrategy) Copy() *DrainStrategy {
	if d == nil {
		return nil
	}

	nd := new(DrainStrategy)
	*nd = *d
	return nd
}

// DeadlineTime returns a boolean whether the drain strategy allows an infinite
// duration or otherwise the deadline time. The force drain is captured by the
// deadline time being in the past.
func (d *DrainStrategy) DeadlineTime() (infinite bool, deadline time.Time) {
	// Treat the nil case as a force drain so during an upgrade where a node may
	// not have a drain strategy but has Drain set to true, it is treated as a
	// force to mimick old behavior.
	if d == nil {
		return false, time.Time{}
	}

	ns := d.Deadline.Nanoseconds()
	switch {
	case ns < 0: // Force
		return false, time.Time{}
	case ns == 0: // Infinite
		return true, time.Time{}
	default:
		return false, d.ForceDeadline
	}
}

func (d *DrainStrategy) Equal(o *DrainStrategy) bool {
	if d == nil && o == nil {
		return true
	} else if o != nil && d == nil {
		return false
	} else if d != nil && o == nil {
		return false
	}

	// Compare values
	if d.ForceDeadline != o.ForceDeadline {
		return false
	} else if d.Deadline != o.Deadline {
		return false
	} else if d.IgnoreSystemJobs != o.IgnoreSystemJobs {
		return false
	}

	return true
}

// Node is a representation of a schedulable client node
type Node struct {
	// ID is a unique identifier for the node. It can be constructed
	// by doing a concatenation of the Name and Datacenter as a simple
	// approach. Alternatively a UUID may be used.
	ID string

	// SecretID is an ID that is only known by the Node and the set of Servers.
	// It is not accessible via the API and is used to authenticate nodes
	// conducting privileged activities.
	SecretID string

	// Datacenter for this node
	Datacenter string

	// Node name
	Name string

	// HTTPAddr is the address on which the Nomad client is listening for http
	// requests
	HTTPAddr string

	// TLSEnabled indicates if the Agent has TLS enabled for the HTTP API
	TLSEnabled bool

	// Attributes is an arbitrary set of key/value
	// data that can be used for constraints. Examples
	// include "kernel.name=linux", "arch=386", "driver.docker=1",
	// "docker.runtime=1.8.3"
	Attributes map[string]string

	// NodeResources captures the available resources on the client.
	NodeResources *NodeResources

	// ReservedResources captures the set resources on the client that are
	// reserved from scheduling.
	ReservedResources *NodeReservedResources

	// Resources is the available resources on the client.
	// For example 'cpu=2' 'memory=2048'
	// COMPAT(0.10): Remove after 0.10
	Resources *Resources

	// Reserved is the set of resources that are reserved,
	// and should be subtracted from the total resources for
	// the purposes of scheduling. This may be provide certain
	// high-watermark tolerances or because of external schedulers
	// consuming resources.
	// COMPAT(0.10): Remove after 0.10
	Reserved *Resources

	// Links are used to 'link' this client to external
	// systems. For example 'consul=foo.dc1' 'aws=i-83212'
	// 'ami=ami-123'
	Links map[string]string

	// Meta is used to associate arbitrary metadata with this
	// client. This is opaque to Nomad.
	Meta map[string]string

	// NodeClass is an opaque identifier used to group nodes
	// together for the purpose of determining scheduling pressure.
	NodeClass string

	// ComputedClass is a unique id that identifies nodes with a common set of
	// attributes and capabilities.
	ComputedClass string

	// COMPAT: Remove in Nomad 0.9
	// Drain is controlled by the servers, and not the client.
	// If true, no jobs will be scheduled to this node, and existing
	// allocations will be drained. Superseded by DrainStrategy in Nomad
	// 0.8 but kept for backward compat.
	Drain bool

	// DrainStrategy determines the node's draining behavior. Will be nil
	// when Drain=false.
	DrainStrategy *DrainStrategy

	// SchedulingEligibility determines whether this node will receive new
	// placements.
	SchedulingEligibility string

	// Status of this node
	Status string

	// StatusDescription is meant to provide more human useful information
	StatusDescription string

	// StatusUpdatedAt is the time stamp at which the state of the node was
	// updated
	StatusUpdatedAt int64

	// Events is the most recent set of events generated for the node,
	// retaining only MaxRetainedNodeEvents number at a time
	Events []*NodeEvent

	// Drivers is a map of driver names to current driver information
	Drivers map[string]*DriverInfo

	// CSIControllerPlugins is a map of plugin names to current CSI Plugin info
	CSIControllerPlugins map[string]*CSIInfo
	// CSINodePlugins is a map of plugin names to current CSI Plugin info
	CSINodePlugins map[string]*CSIInfo

	// HostVolumes is a map of host volume names to their configuration
	HostVolumes map[string]*ClientHostVolumeConfig

	// Raft Indexes
	CreateIndex uint64
	ModifyIndex uint64
}

// Ready returns true if the node is ready for running allocations
func (n *Node) Ready() bool {
	// Drain is checked directly to support pre-0.8 Node data
	return n.Status == NodeStatusReady && !n.Drain && n.SchedulingEligibility == NodeSchedulingEligible
}

func (n *Node) Canonicalize() {
	if n == nil {
		return
	}

	// COMPAT Remove in 0.10
	// In v0.8.0 we introduced scheduling eligibility, so we need to set it for
	// upgrading nodes
	if n.SchedulingEligibility == "" {
		if n.Drain {
			n.SchedulingEligibility = NodeSchedulingIneligible
		} else {
			n.SchedulingEligibility = NodeSchedulingEligible
		}
	}

	// COMPAT remove in 1.0
	// In v0.12.0 we introduced a separate node specific network resource struct
	// so we need to covert any pre 0.12 clients to the correct struct
	if n.NodeResources != nil && n.NodeResources.NodeNetworks == nil {
		if n.NodeResources.Networks != nil {
			for _, nr := range n.NodeResources.Networks {
				nnr := &NodeNetworkResource{
					Mode:   nr.Mode,
					Speed:  nr.MBits,
					Device: nr.Device,
				}
				if nr.IP != "" {
					nnr.Addresses = []NodeNetworkAddress{
						{
							Alias:   "default",
							Address: nr.IP,
						},
					}
				}
				n.NodeResources.NodeNetworks = append(n.NodeResources.NodeNetworks, nnr)
			}
		}
	}
}

func (n *Node) Copy() *Node {
	if n == nil {
		return nil
	}
	nn := new(Node)
	*nn = *n
	nn.Attributes = helper.CopyMapStringString(nn.Attributes)
	nn.Resources = nn.Resources.Copy()
	nn.Reserved = nn.Reserved.Copy()
	nn.NodeResources = nn.NodeResources.Copy()
	nn.ReservedResources = nn.ReservedResources.Copy()
	nn.Links = helper.CopyMapStringString(nn.Links)
	nn.Meta = helper.CopyMapStringString(nn.Meta)
	nn.Events = copyNodeEvents(n.Events)
	nn.DrainStrategy = nn.DrainStrategy.Copy()
	nn.CSIControllerPlugins = copyNodeCSI(nn.CSIControllerPlugins)
	nn.CSINodePlugins = copyNodeCSI(nn.CSINodePlugins)
	nn.Drivers = copyNodeDrivers(n.Drivers)
	nn.HostVolumes = copyNodeHostVolumes(n.HostVolumes)
	return nn
}

// copyNodeEvents is a helper to copy a list of NodeEvent's
func copyNodeEvents(events []*NodeEvent) []*NodeEvent {
	l := len(events)
	if l == 0 {
		return nil
	}

	c := make([]*NodeEvent, l)
	for i, event := range events {
		c[i] = event.Copy()
	}
	return c
}

// copyNodeCSI is a helper to copy a map of CSIInfo
func copyNodeCSI(plugins map[string]*CSIInfo) map[string]*CSIInfo {
	l := len(plugins)
	if l == 0 {
		return nil
	}

	c := make(map[string]*CSIInfo, l)
	for plugin, info := range plugins {
		c[plugin] = info.Copy()
	}

	return c
}

// copyNodeDrivers is a helper to copy a map of DriverInfo
func copyNodeDrivers(drivers map[string]*DriverInfo) map[string]*DriverInfo {
	l := len(drivers)
	if l == 0 {
		return nil
	}

	c := make(map[string]*DriverInfo, l)
	for driver, info := range drivers {
		c[driver] = info.Copy()
	}
	return c
}

// copyNodeHostVolumes is a helper to copy a map of string to Volume
func copyNodeHostVolumes(volumes map[string]*ClientHostVolumeConfig) map[string]*ClientHostVolumeConfig {
	l := len(volumes)
	if l == 0 {
		return nil
	}

	c := make(map[string]*ClientHostVolumeConfig, l)
	for volume, v := range volumes {
		c[volume] = v.Copy()
	}

	return c
}

// TerminalStatus returns if the current status is terminal and
// will no longer transition.
func (n *Node) TerminalStatus() bool {
	switch n.Status {
	case NodeStatusDown:
		return true
	default:
		return false
	}
}

// COMPAT(0.11): Remove in 0.11
// ComparableReservedResources returns the reserved resouces on the node
// handling upgrade paths. Reserved networks must be handled separately. After
// 0.11 calls to this should be replaced with:
// node.ReservedResources.Comparable()
func (n *Node) ComparableReservedResources() *ComparableResources {
	// See if we can no-op
	if n.Reserved == nil && n.ReservedResources == nil {
		return nil
	}

	// Node already has 0.9+ behavior
	if n.ReservedResources != nil {
		return n.ReservedResources.Comparable()
	}

	// Upgrade path
	return &ComparableResources{
		Flattened: AllocatedTaskResources{
			Cpu: AllocatedCpuResources{
				CpuShares: int64(n.Reserved.CPU),
			},
			Memory: AllocatedMemoryResources{
				MemoryMB: int64(n.Reserved.MemoryMB),
			},
		},
		Shared: AllocatedSharedResources{
			DiskMB: int64(n.Reserved.DiskMB),
		},
	}
}

// COMPAT(0.11): Remove in 0.11
// ComparableResources returns the resouces on the node
// handling upgrade paths. Networking must be handled separately. After 0.11
// calls to this should be replaced with: node.NodeResources.Comparable()
func (n *Node) ComparableResources() *ComparableResources {
	// Node already has 0.9+ behavior
	if n.NodeResources != nil {
		return n.NodeResources.Comparable()
	}

	// Upgrade path
	return &ComparableResources{
		Flattened: AllocatedTaskResources{
			Cpu: AllocatedCpuResources{
				CpuShares: int64(n.Resources.CPU),
			},
			Memory: AllocatedMemoryResources{
				MemoryMB: int64(n.Resources.MemoryMB),
			},
		},
		Shared: AllocatedSharedResources{
			DiskMB: int64(n.Resources.DiskMB),
		},
	}
}

// Stub returns a summarized version of the node
func (n *Node) Stub(fields *NodeStubFields) *NodeListStub {

	addr, _, _ := net.SplitHostPort(n.HTTPAddr)

	s := &NodeListStub{
		Address:               addr,
		ID:                    n.ID,
		Datacenter:            n.Datacenter,
		Name:                  n.Name,
		NodeClass:             n.NodeClass,
		Version:               n.Attributes["nomad.version"],
		Drain:                 n.Drain,
		SchedulingEligibility: n.SchedulingEligibility,
		Status:                n.Status,
		StatusDescription:     n.StatusDescription,
		Drivers:               n.Drivers,
		HostVolumes:           n.HostVolumes,
		CreateIndex:           n.CreateIndex,
		ModifyIndex:           n.ModifyIndex,
	}

	if fields != nil {
		if fields.Resources {
			s.NodeResources = n.NodeResources
			s.ReservedResources = n.ReservedResources
		}
	}

	return s
}

// NodeListStub is used to return a subset of job information
// for the job list
type NodeListStub struct {
	Address               string
	ID                    string
	Datacenter            string
	Name                  string
	NodeClass             string
	Version               string
	Drain                 bool
	SchedulingEligibility string
	Status                string
	StatusDescription     string
	Drivers               map[string]*DriverInfo
	HostVolumes           map[string]*ClientHostVolumeConfig
	NodeResources         *NodeResources         `json:",omitempty"`
	ReservedResources     *NodeReservedResources `json:",omitempty"`
	CreateIndex           uint64
	ModifyIndex           uint64
}

// NodeStubFields defines which fields are included in the NodeListStub.
type NodeStubFields struct {
	Resources bool
}

// Resources is used to define the resources available
// on a client
type Resources struct {
	CPU      int
	MemoryMB int
	DiskMB   int
	IOPS     int // COMPAT(0.10): Only being used to issue warnings
	Networks Networks
	Devices  ResourceDevices
}

const (
	BytesInMegabyte = 1024 * 1024
)

// DefaultResources is a small resources object that contains the
// default resources requests that we will provide to an object.
// ---  THIS FUNCTION IS REPLICATED IN api/resources.go and should
// be kept in sync.
func DefaultResources() *Resources {
	return &Resources{
		CPU:      100,
		MemoryMB: 300,
	}
}

// MinResources is a small resources object that contains the
// absolute minimum resources that we will provide to an object.
// This should not be confused with the defaults which are
// provided in Canonicalize() ---  THIS FUNCTION IS REPLICATED IN
// api/resources.go and should be kept in sync.
func MinResources() *Resources {
	return &Resources{
		CPU:      1,
		MemoryMB: 10,
	}
}

// DiskInBytes returns the amount of disk resources in bytes.
func (r *Resources) DiskInBytes() int64 {
	return int64(r.DiskMB * BytesInMegabyte)
}

func (r *Resources) Validate() error {
	var mErr multierror.Error
	if err := r.MeetsMinResources(); err != nil {
		mErr.Errors = append(mErr.Errors, err)
	}

	// Ensure the task isn't asking for disk resources
	if r.DiskMB > 0 {
		mErr.Errors = append(mErr.Errors, errors.New("Task can't ask for disk resources, they have to be specified at the task group level."))
	}

	for i, d := range r.Devices {
		if err := d.Validate(); err != nil {
			mErr.Errors = append(mErr.Errors, fmt.Errorf("device %d failed validation: %v", i+1, err))
		}
	}

	return mErr.ErrorOrNil()
}

// Merge merges this resource with another resource.
// COMPAT(0.10): Remove in 0.10
func (r *Resources) Merge(other *Resources) {
	if other.CPU != 0 {
		r.CPU = other.CPU
	}
	if other.MemoryMB != 0 {
		r.MemoryMB = other.MemoryMB
	}
	if other.DiskMB != 0 {
		r.DiskMB = other.DiskMB
	}
	if len(other.Networks) != 0 {
		r.Networks = other.Networks
	}
	if len(other.Devices) != 0 {
		r.Devices = other.Devices
	}
}

// COMPAT(0.10): Remove in 0.10
func (r *Resources) Equals(o *Resources) bool {
	if r == o {
		return true
	}
	if r == nil || o == nil {
		return false
	}
	return r.CPU == o.CPU &&
		r.MemoryMB == o.MemoryMB &&
		r.DiskMB == o.DiskMB &&
		r.IOPS == o.IOPS &&
		r.Networks.Equals(&o.Networks) &&
		r.Devices.Equals(&o.Devices)
}

// COMPAT(0.10): Remove in 0.10
// ResourceDevices are part of Resources
type ResourceDevices []*RequestedDevice

// COMPAT(0.10): Remove in 0.10
// Equals ResourceDevices as set keyed by Name
func (d *ResourceDevices) Equals(o *ResourceDevices) bool {
	if d == o {
		return true
	}
	if d == nil || o == nil {
		return false
	}
	if len(*d) != len(*o) {
		return false
	}
	m := make(map[string]*RequestedDevice, len(*d))
	for _, e := range *d {
		m[e.Name] = e
	}
	for _, oe := range *o {
		de, ok := m[oe.Name]
		if !ok || !de.Equals(oe) {
			return false
		}
	}
	return true
}

// COMPAT(0.10): Remove in 0.10
func (r *Resources) Canonicalize() {
	// Ensure that an empty and nil slices are treated the same to avoid scheduling
	// problems since we use reflect DeepEquals.
	if len(r.Networks) == 0 {
		r.Networks = nil
	}
	if len(r.Devices) == 0 {
		r.Devices = nil
	}

	for _, n := range r.Networks {
		n.Canonicalize()
	}
}

// MeetsMinResources returns an error if the resources specified are less than
// the minimum allowed.
// This is based on the minimums defined in the Resources type
// COMPAT(0.10): Remove in 0.10
func (r *Resources) MeetsMinResources() error {
	var mErr multierror.Error
	minResources := MinResources()
	if r.CPU < minResources.CPU {
		mErr.Errors = append(mErr.Errors, fmt.Errorf("minimum CPU value is %d; got %d", minResources.CPU, r.CPU))
	}
	if r.MemoryMB < minResources.MemoryMB {
		mErr.Errors = append(mErr.Errors, fmt.Errorf("minimum MemoryMB value is %d; got %d", minResources.MemoryMB, r.MemoryMB))
	}
	return mErr.ErrorOrNil()
}

// Copy returns a deep copy of the resources
func (r *Resources) Copy() *Resources {
	if r == nil {
		return nil
	}
	newR := new(Resources)
	*newR = *r

	// Copy the network objects
	newR.Networks = r.Networks.Copy()

	// Copy the devices
	if r.Devices != nil {
		n := len(r.Devices)
		newR.Devices = make([]*RequestedDevice, n)
		for i := 0; i < n; i++ {
			newR.Devices[i] = r.Devices[i].Copy()
		}
	}

	return newR
}

// NetIndex finds the matching net index using device name
// COMPAT(0.10): Remove in 0.10
func (r *Resources) NetIndex(n *NetworkResource) int {
	return r.Networks.NetIndex(n)
}

// Superset checks if one set of resources is a superset
// of another. This ignores network resources, and the NetworkIndex
// should be used for that.
// COMPAT(0.10): Remove in 0.10
func (r *Resources) Superset(other *Resources) (bool, string) {
	if r.CPU < other.CPU {
		return false, "cpu"
	}
	if r.MemoryMB < other.MemoryMB {
		return false, "memory"
	}
	if r.DiskMB < other.DiskMB {
		return false, "disk"
	}
	return true, ""
}

// Add adds the resources of the delta to this, potentially
// returning an error if not possible.
// COMPAT(0.10): Remove in 0.10
func (r *Resources) Add(delta *Resources) {
	if delta == nil {
		return
	}

	r.CPU += delta.CPU
	r.MemoryMB += delta.MemoryMB
	r.DiskMB += delta.DiskMB

	for _, n := range delta.Networks {
		// Find the matching interface by IP or CIDR
		idx := r.NetIndex(n)
		if idx == -1 {
			r.Networks = append(r.Networks, n.Copy())
		} else {
			r.Networks[idx].Add(n)
		}
	}
}

// COMPAT(0.10): Remove in 0.10
func (r *Resources) GoString() string {
	return fmt.Sprintf("*%#v", *r)
}

// NodeNetworkResource is used to describe a fingerprinted network of a node
type NodeNetworkResource struct {
	Mode string // host for physical networks, cni/<name> for cni networks

	// The following apply only to host networks
	Device     string // interface name
	MacAddress string
	Speed      int

	Addresses []NodeNetworkAddress // not valid for cni, for bridge there will only be 1 ip
}

func (n *NodeNetworkResource) Equals(o *NodeNetworkResource) bool {
	return reflect.DeepEqual(n, o)
}

func (n *NodeNetworkResource) HasAlias(alias string) bool {
	for _, addr := range n.Addresses {
		if addr.Alias == alias {
			return true
		}
	}
	return false
}

type NodeNetworkAF string

const (
	NodeNetworkAF_IPv4 NodeNetworkAF = "ipv4"
	NodeNetworkAF_IPv6 NodeNetworkAF = "ipv6"
)

type NodeNetworkAddress struct {
	Family        NodeNetworkAF
	Alias         string
	Address       string
	ReservedPorts string
	Gateway       string // default route for this address
}

type AllocatedPortMapping struct {
	Label  string
	Value  int
	To     int
	HostIP string
}

type AllocatedPorts []AllocatedPortMapping

func (p AllocatedPorts) Get(label string) (AllocatedPortMapping, bool) {
	for _, port := range p {
		if port.Label == label {
			return port, true
		}
	}

	return AllocatedPortMapping{}, false
}

type Port struct {
	// Label is the key for HCL port stanzas: port "foo" {}
	Label string

	// Value is the static or dynamic port value. For dynamic ports this
	// will be 0 in the jobspec and set by the scheduler.
	Value int

	// To is the port inside a network namespace where this port is
	// forwarded. -1 is an internal sentinel value used by Consul Connect
	// to mean "same as the host port."
	To int

	// HostNetwork is the name of the network this port should be assigned
	// to. Jobs with a HostNetwork set can only be placed on nodes with
	// that host network available.
	HostNetwork string
}

type DNSConfig struct {
	Servers  []string
	Searches []string
	Options  []string
}

func (d *DNSConfig) Copy() *DNSConfig {
	if d == nil {
		return nil
	}
	newD := new(DNSConfig)
	newD.Servers = make([]string, len(d.Servers))
	copy(newD.Servers, d.Servers)
	newD.Searches = make([]string, len(d.Searches))
	copy(newD.Searches, d.Searches)
	newD.Options = make([]string, len(d.Options))
	copy(newD.Options, d.Options)
	return newD
}

// NetworkResource is used to represent available network
// resources
type NetworkResource struct {
	Mode          string     // Mode of the network
	Device        string     // Name of the device
	CIDR          string     // CIDR block of addresses
	IP            string     // Host IP address
	MBits         int        // Throughput
	DNS           *DNSConfig // DNS Configuration
	ReservedPorts []Port     // Host Reserved ports
	DynamicPorts  []Port     // Host Dynamically assigned ports
}

func (nr *NetworkResource) Hash() uint32 {
	var data []byte
	data = append(data, []byte(fmt.Sprintf("%s%s%s%s%d", nr.Mode, nr.Device, nr.CIDR, nr.IP, nr.MBits))...)

	for i, port := range nr.ReservedPorts {
		data = append(data, []byte(fmt.Sprintf("r%d%s%d%d", i, port.Label, port.Value, port.To))...)
	}

	for i, port := range nr.DynamicPorts {
		data = append(data, []byte(fmt.Sprintf("d%d%s%d%d", i, port.Label, port.Value, port.To))...)
	}

	return crc32.ChecksumIEEE(data)
}

func (nr *NetworkResource) Equals(other *NetworkResource) bool {
	return nr.Hash() == other.Hash()
}

func (n *NetworkResource) Canonicalize() {
	// Ensure that an empty and nil slices are treated the same to avoid scheduling
	// problems since we use reflect DeepEquals.
	if len(n.ReservedPorts) == 0 {
		n.ReservedPorts = nil
	}
	if len(n.DynamicPorts) == 0 {
		n.DynamicPorts = nil
	}

	for i, p := range n.DynamicPorts {
		if p.HostNetwork == "" {
			n.DynamicPorts[i].HostNetwork = "default"
		}
	}
	for i, p := range n.ReservedPorts {
		if p.HostNetwork == "" {
			n.ReservedPorts[i].HostNetwork = "default"
		}
	}
}

// Copy returns a deep copy of the network resource
func (n *NetworkResource) Copy() *NetworkResource {
	if n == nil {
		return nil
	}
	newR := new(NetworkResource)
	*newR = *n
	if n.ReservedPorts != nil {
		newR.ReservedPorts = make([]Port, len(n.ReservedPorts))
		copy(newR.ReservedPorts, n.ReservedPorts)
	}
	if n.DynamicPorts != nil {
		newR.DynamicPorts = make([]Port, len(n.DynamicPorts))
		copy(newR.DynamicPorts, n.DynamicPorts)
	}
	return newR
}

// Add adds the resources of the delta to this, potentially
// returning an error if not possible.
func (n *NetworkResource) Add(delta *NetworkResource) {
	if len(delta.ReservedPorts) > 0 {
		n.ReservedPorts = append(n.ReservedPorts, delta.ReservedPorts...)
	}
	n.MBits += delta.MBits
	n.DynamicPorts = append(n.DynamicPorts, delta.DynamicPorts...)
}

func (n *NetworkResource) GoString() string {
	return fmt.Sprintf("*%#v", *n)
}

// PortLabels returns a map of port labels to their assigned host ports.
func (n *NetworkResource) PortLabels() map[string]int {
	num := len(n.ReservedPorts) + len(n.DynamicPorts)
	labelValues := make(map[string]int, num)
	for _, port := range n.ReservedPorts {
		labelValues[port.Label] = port.Value
	}
	for _, port := range n.DynamicPorts {
		labelValues[port.Label] = port.Value
	}
	return labelValues
}

// Networks defined for a task on the Resources struct.
type Networks []*NetworkResource

func (ns Networks) Copy() Networks {
	if len(ns) == 0 {
		return nil
	}

	out := make([]*NetworkResource, len(ns))
	for i := range ns {
		out[i] = ns[i].Copy()
	}
	return out
}

// Port assignment and IP for the given label or empty values.
func (ns Networks) Port(label string) AllocatedPortMapping {
	for _, n := range ns {
		for _, p := range n.ReservedPorts {
			if p.Label == label {
				return AllocatedPortMapping{
					Label:  label,
					Value:  p.Value,
					To:     p.To,
					HostIP: n.IP,
				}
			}
		}
		for _, p := range n.DynamicPorts {
			if p.Label == label {
				return AllocatedPortMapping{
					Label:  label,
					Value:  p.Value,
					To:     p.To,
					HostIP: n.IP,
				}
			}
		}
	}
	return AllocatedPortMapping{}
}

func (ns Networks) NetIndex(n *NetworkResource) int {
	for idx, net := range ns {
		if net.Device == n.Device {
			return idx
		}
	}
	return -1
}

// RequestedDevice is used to request a device for a task.
type RequestedDevice struct {
	// Name is the request name. The possible values are as follows:
	// * <type>: A single value only specifies the type of request.
	// * <vendor>/<type>: A single slash delimiter assumes the vendor and type of device is specified.
	// * <vendor>/<type>/<name>: Two slash delimiters assume vendor, type and specific model are specified.
	//
	// Examples are as follows:
	// * "gpu"
	// * "nvidia/gpu"
	// * "nvidia/gpu/GTX2080Ti"
	Name string

	// Count is the number of requested devices
	Count uint64

	// Constraints are a set of constraints to apply when selecting the device
	// to use.
	Constraints Constraints

	// Affinities are a set of affinities to apply when selecting the device
	// to use.
	Affinities Affinities
}

func (r *RequestedDevice) Equals(o *RequestedDevice) bool {
	if r == o {
		return true
	}
	if r == nil || o == nil {
		return false
	}
	return r.Name == o.Name &&
		r.Count == o.Count &&
		r.Constraints.Equals(&o.Constraints) &&
		r.Affinities.Equals(&o.Affinities)
}

func (r *RequestedDevice) Copy() *RequestedDevice {
	if r == nil {
		return nil
	}

	nr := *r
	nr.Constraints = CopySliceConstraints(nr.Constraints)
	nr.Affinities = CopySliceAffinities(nr.Affinities)

	return &nr
}

func (r *RequestedDevice) ID() *DeviceIdTuple {
	if r == nil || r.Name == "" {
		return nil
	}

	parts := strings.SplitN(r.Name, "/", 3)
	switch len(parts) {
	case 1:
		return &DeviceIdTuple{
			Type: parts[0],
		}
	case 2:
		return &DeviceIdTuple{
			Vendor: parts[0],
			Type:   parts[1],
		}
	default:
		return &DeviceIdTuple{
			Vendor: parts[0],
			Type:   parts[1],
			Name:   parts[2],
		}
	}
}

func (r *RequestedDevice) Validate() error {
	if r == nil {
		return nil
	}

	var mErr multierror.Error
	if r.Name == "" {
		_ = multierror.Append(&mErr, errors.New("device name must be given as one of the following: type, vendor/type, or vendor/type/name"))
	}

	for idx, constr := range r.Constraints {
		// Ensure that the constraint doesn't use an operand we do not allow
		switch constr.Operand {
		case ConstraintDistinctHosts, ConstraintDistinctProperty:
			outer := fmt.Errorf("Constraint %d validation failed: using unsupported operand %q", idx+1, constr.Operand)
			_ = multierror.Append(&mErr, outer)
		default:
			if err := constr.Validate(); err != nil {
				outer := fmt.Errorf("Constraint %d validation failed: %s", idx+1, err)
				_ = multierror.Append(&mErr, outer)
			}
		}
	}
	for idx, affinity := range r.Affinities {
		if err := affinity.Validate(); err != nil {
			outer := fmt.Errorf("Affinity %d validation failed: %s", idx+1, err)
			_ = multierror.Append(&mErr, outer)
		}
	}

	return mErr.ErrorOrNil()
}

// NodeResources is used to define the resources available on a client node.
type NodeResources struct {
	Cpu          NodeCpuResources
	Memory       NodeMemoryResources
	Disk         NodeDiskResources
	Networks     Networks
	NodeNetworks []*NodeNetworkResource
	Devices      []*NodeDeviceResource
}

func (n *NodeResources) Copy() *NodeResources {
	if n == nil {
		return nil
	}

	newN := new(NodeResources)
	*newN = *n

	// Copy the networks
	newN.Networks = n.Networks.Copy()

	// Copy the devices
	if n.Devices != nil {
		devices := len(n.Devices)
		newN.Devices = make([]*NodeDeviceResource, devices)
		for i := 0; i < devices; i++ {
			newN.Devices[i] = n.Devices[i].Copy()
		}
	}

	return newN
}

// Comparable returns a comparable version of the nodes resources. This
// conversion can be lossy so care must be taken when using it.
func (n *NodeResources) Comparable() *ComparableResources {
	if n == nil {
		return nil
	}

	c := &ComparableResources{
		Flattened: AllocatedTaskResources{
			Cpu: AllocatedCpuResources{
				CpuShares: n.Cpu.CpuShares,
			},
			Memory: AllocatedMemoryResources{
				MemoryMB: n.Memory.MemoryMB,
			},
			Networks: n.Networks,
		},
		Shared: AllocatedSharedResources{
			DiskMB: n.Disk.DiskMB,
		},
	}
	return c
}

func (n *NodeResources) Merge(o *NodeResources) {
	if o == nil {
		return
	}

	n.Cpu.Merge(&o.Cpu)
	n.Memory.Merge(&o.Memory)
	n.Disk.Merge(&o.Disk)

	if len(o.Networks) != 0 {
		n.Networks = append(n.Networks, o.Networks...)
	}

	if len(o.Devices) != 0 {
		n.Devices = o.Devices
	}

	if len(o.NodeNetworks) != 0 {
		lookupNetwork := func(nets []*NodeNetworkResource, name string) (int, *NodeNetworkResource) {
			for i, nw := range nets {
				if nw.Device == name {
					return i, nw
				}
			}
			return 0, nil
		}

		for _, nw := range o.NodeNetworks {
			if i, nnw := lookupNetwork(n.NodeNetworks, nw.Device); nnw != nil {
				n.NodeNetworks[i] = nw
			} else {
				n.NodeNetworks = append(n.NodeNetworks, nw)
			}
		}
	}
}

func (n *NodeResources) Equals(o *NodeResources) bool {
	if o == nil && n == nil {
		return true
	} else if o == nil {
		return false
	} else if n == nil {
		return false
	}

	if !n.Cpu.Equals(&o.Cpu) {
		return false
	}
	if !n.Memory.Equals(&o.Memory) {
		return false
	}
	if !n.Disk.Equals(&o.Disk) {
		return false
	}
	if !n.Networks.Equals(&o.Networks) {
		return false
	}

	// Check the devices
	if !DevicesEquals(n.Devices, o.Devices) {
		return false
	}

	if !NodeNetworksEquals(n.NodeNetworks, o.NodeNetworks) {
		return false
	}

	return true
}

// Equals equates Networks as a set
func (ns *Networks) Equals(o *Networks) bool {
	if ns == o {
		return true
	}
	if ns == nil || o == nil {
		return false
	}
	if len(*ns) != len(*o) {
		return false
	}
SETEQUALS:
	for _, ne := range *ns {
		for _, oe := range *o {
			if ne.Equals(oe) {
				continue SETEQUALS
			}
		}
		return false
	}
	return true
}

// DevicesEquals returns true if the two device arrays are set equal
func DevicesEquals(d1, d2 []*NodeDeviceResource) bool {
	if len(d1) != len(d2) {
		return false
	}
	idMap := make(map[DeviceIdTuple]*NodeDeviceResource, len(d1))
	for _, d := range d1 {
		idMap[*d.ID()] = d
	}
	for _, otherD := range d2 {
		if d, ok := idMap[*otherD.ID()]; !ok || !d.Equals(otherD) {
			return false
		}
	}

	return true
}

func NodeNetworksEquals(n1, n2 []*NodeNetworkResource) bool {
	if len(n1) != len(n2) {
		return false
	}

	netMap := make(map[string]*NodeNetworkResource, len(n1))
	for _, n := range n1 {
		netMap[n.Device] = n
	}
	for _, otherN := range n2 {
		if n, ok := netMap[otherN.Device]; !ok || !n.Equals(otherN) {
			return false
		}
	}

	return true

}

// NodeCpuResources captures the CPU resources of the node.
type NodeCpuResources struct {
	// CpuShares is the CPU shares available. This is calculated by number of
	// cores multiplied by the core frequency.
	CpuShares int64
}

func (n *NodeCpuResources) Merge(o *NodeCpuResources) {
	if o == nil {
		return
	}

	if o.CpuShares != 0 {
		n.CpuShares = o.CpuShares
	}
}

func (n *NodeCpuResources) Equals(o *NodeCpuResources) bool {
	if o == nil && n == nil {
		return true
	} else if o == nil {
		return false
	} else if n == nil {
		return false
	}

	if n.CpuShares != o.CpuShares {
		return false
	}

	return true
}

// NodeMemoryResources captures the memory resources of the node
type NodeMemoryResources struct {
	// MemoryMB is the total available memory on the node
	MemoryMB int64
}

func (n *NodeMemoryResources) Merge(o *NodeMemoryResources) {
	if o == nil {
		return
	}

	if o.MemoryMB != 0 {
		n.MemoryMB = o.MemoryMB
	}
}

func (n *NodeMemoryResources) Equals(o *NodeMemoryResources) bool {
	if o == nil && n == nil {
		return true
	} else if o == nil {
		return false
	} else if n == nil {
		return false
	}

	if n.MemoryMB != o.MemoryMB {
		return false
	}

	return true
}

// NodeDiskResources captures the disk resources of the node
type NodeDiskResources struct {
	// DiskMB is the total available disk space on the node
	DiskMB int64
}

func (n *NodeDiskResources) Merge(o *NodeDiskResources) {
	if o == nil {
		return
	}
	if o.DiskMB != 0 {
		n.DiskMB = o.DiskMB
	}
}

func (n *NodeDiskResources) Equals(o *NodeDiskResources) bool {
	if o == nil && n == nil {
		return true
	} else if o == nil {
		return false
	} else if n == nil {
		return false
	}

	if n.DiskMB != o.DiskMB {
		return false
	}

	return true
}

// DeviceIdTuple is the tuple that identifies a device
type DeviceIdTuple struct {
	Vendor string
	Type   string
	Name   string
}

func (d *DeviceIdTuple) String() string {
	if d == nil {
		return ""
	}

	return fmt.Sprintf("%s/%s/%s", d.Vendor, d.Type, d.Name)
}

// Matches returns if this Device ID is a superset of the passed ID.
func (id *DeviceIdTuple) Matches(other *DeviceIdTuple) bool {
	if other == nil {
		return false
	}

	if other.Name != "" && other.Name != id.Name {
		return false
	}

	if other.Vendor != "" && other.Vendor != id.Vendor {
		return false
	}

	if other.Type != "" && other.Type != id.Type {
		return false
	}

	return true
}

// Equals returns if this Device ID is the same as the passed ID.
func (id *DeviceIdTuple) Equals(o *DeviceIdTuple) bool {
	if id == nil && o == nil {
		return true
	} else if id == nil || o == nil {
		return false
	}

	return o.Vendor == id.Vendor && o.Type == id.Type && o.Name == id.Name
}

// NodeDeviceResource captures a set of devices sharing a common
// vendor/type/device_name tuple.
type NodeDeviceResource struct {
	Vendor     string
	Type       string
	Name       string
	Instances  []*NodeDevice
	Attributes map[string]*psstructs.Attribute
}

func (n *NodeDeviceResource) ID() *DeviceIdTuple {
	if n == nil {
		return nil
	}

	return &DeviceIdTuple{
		Vendor: n.Vendor,
		Type:   n.Type,
		Name:   n.Name,
	}
}

func (n *NodeDeviceResource) Copy() *NodeDeviceResource {
	if n == nil {
		return nil
	}

	// Copy the primitives
	nn := *n

	// Copy the device instances
	if l := len(nn.Instances); l != 0 {
		nn.Instances = make([]*NodeDevice, 0, l)
		for _, d := range n.Instances {
			nn.Instances = append(nn.Instances, d.Copy())
		}
	}

	// Copy the Attributes
	nn.Attributes = psstructs.CopyMapStringAttribute(nn.Attributes)

	return &nn
}

func (n *NodeDeviceResource) Equals(o *NodeDeviceResource) bool {
	if o == nil && n == nil {
		return true
	} else if o == nil {
		return false
	} else if n == nil {
		return false
	}

	if n.Vendor != o.Vendor {
		return false
	} else if n.Type != o.Type {
		return false
	} else if n.Name != o.Name {
		return false
	}

	// Check the attributes
	if len(n.Attributes) != len(o.Attributes) {
		return false
	}
	for k, v := range n.Attributes {
		if otherV, ok := o.Attributes[k]; !ok || v != otherV {
			return false
		}
	}

	// Check the instances
	if len(n.Instances) != len(o.Instances) {
		return false
	}
	idMap := make(map[string]*NodeDevice, len(n.Instances))
	for _, d := range n.Instances {
		idMap[d.ID] = d
	}
	for _, otherD := range o.Instances {
		if d, ok := idMap[otherD.ID]; !ok || !d.Equals(otherD) {
			return false
		}
	}

	return true
}

// NodeDevice is an instance of a particular device.
type NodeDevice struct {
	// ID is the ID of the device.
	ID string

	// Healthy captures whether the device is healthy.
	Healthy bool

	// HealthDescription is used to provide a human readable description of why
	// the device may be unhealthy.
	HealthDescription string

	// Locality stores HW locality information for the node to optionally be
	// used when making placement decisions.
	Locality *NodeDeviceLocality
}

func (n *NodeDevice) Equals(o *NodeDevice) bool {
	if o == nil && n == nil {
		return true
	} else if o == nil {
		return false
	} else if n == nil {
		return false
	}

	if n.ID != o.ID {
		return false
	} else if n.Healthy != o.Healthy {
		return false
	} else if n.HealthDescription != o.HealthDescription {
		return false
	} else if !n.Locality.Equals(o.Locality) {
		return false
	}

	return false
}

func (n *NodeDevice) Copy() *NodeDevice {
	if n == nil {
		return nil
	}

	// Copy the primitives
	nn := *n

	// Copy the locality
	nn.Locality = nn.Locality.Copy()

	return &nn
}

// NodeDeviceLocality stores information about the devices hardware locality on
// the node.
type NodeDeviceLocality struct {
	// PciBusID is the PCI Bus ID for the device.
	PciBusID string
}

func (n *NodeDeviceLocality) Equals(o *NodeDeviceLocality) bool {
	if o == nil && n == nil {
		return true
	} else if o == nil {
		return false
	} else if n == nil {
		return false
	}

	if n.PciBusID != o.PciBusID {
		return false
	}

	return true
}

func (n *NodeDeviceLocality) Copy() *NodeDeviceLocality {
	if n == nil {
		return nil
	}

	// Copy the primitives
	nn := *n
	return &nn
}

// NodeReservedResources is used to capture the resources on a client node that
// should be reserved and not made available to jobs.
type NodeReservedResources struct {
	Cpu      NodeReservedCpuResources
	Memory   NodeReservedMemoryResources
	Disk     NodeReservedDiskResources
	Networks NodeReservedNetworkResources
}

func (n *NodeReservedResources) Copy() *NodeReservedResources {
	if n == nil {
		return nil
	}
	newN := new(NodeReservedResources)
	*newN = *n
	return newN
}

// Comparable returns a comparable version of the node's reserved resources. The
// returned resources doesn't contain any network information. This conversion
// can be lossy so care must be taken when using it.
func (n *NodeReservedResources) Comparable() *ComparableResources {
	if n == nil {
		return nil
	}

	c := &ComparableResources{
		Flattened: AllocatedTaskResources{
			Cpu: AllocatedCpuResources{
				CpuShares: n.Cpu.CpuShares,
			},
			Memory: AllocatedMemoryResources{
				MemoryMB: n.Memory.MemoryMB,
			},
		},
		Shared: AllocatedSharedResources{
			DiskMB: n.Disk.DiskMB,
		},
	}
	return c
}

// NodeReservedCpuResources captures the reserved CPU resources of the node.
type NodeReservedCpuResources struct {
	CpuShares int64
}

// NodeReservedMemoryResources captures the reserved memory resources of the node.
type NodeReservedMemoryResources struct {
	MemoryMB int64
}

// NodeReservedDiskResources captures the reserved disk resources of the node.
type NodeReservedDiskResources struct {
	DiskMB int64
}

// NodeReservedNetworkResources captures the reserved network resources of the node.
type NodeReservedNetworkResources struct {
	// ReservedHostPorts is the set of ports reserved on all host network
	// interfaces. Its format is a comma separate list of integers or integer
	// ranges. (80,443,1000-2000,2005)
	ReservedHostPorts string
}

// ParsePortHostPorts returns the reserved host ports.
func (n *NodeReservedNetworkResources) ParseReservedHostPorts() ([]uint64, error) {
	return ParsePortRanges(n.ReservedHostPorts)
}

// AllocatedResources is the set of resources to be used by an allocation.
type AllocatedResources struct {
	// Tasks is a mapping of task name to the resources for the task.
	Tasks          map[string]*AllocatedTaskResources
	TaskLifecycles map[string]*TaskLifecycleConfig

	// Shared is the set of resource that are shared by all tasks in the group.
	Shared AllocatedSharedResources
}

func (a *AllocatedResources) Copy() *AllocatedResources {
	if a == nil {
		return nil
	}

	out := AllocatedResources{
		Shared: a.Shared.Copy(),
	}

	if a.Tasks != nil {
		out.Tasks = make(map[string]*AllocatedTaskResources, len(out.Tasks))
		for task, resource := range a.Tasks {
			out.Tasks[task] = resource.Copy()
		}
	}
	if a.TaskLifecycles != nil {
		out.TaskLifecycles = make(map[string]*TaskLifecycleConfig, len(out.TaskLifecycles))
		for task, lifecycle := range a.TaskLifecycles {
			out.TaskLifecycles[task] = lifecycle.Copy()
		}

	}

	return &out
}

// Comparable returns a comparable version of the allocations allocated
// resources. This conversion can be lossy so care must be taken when using it.
func (a *AllocatedResources) Comparable() *ComparableResources {
	if a == nil {
		return nil
	}

	c := &ComparableResources{
		Shared: a.Shared,
	}

	prestartSidecarTasks := &AllocatedTaskResources{}
	prestartEphemeralTasks := &AllocatedTaskResources{}
	main := &AllocatedTaskResources{}
	poststopTasks := &AllocatedTaskResources{}

	for taskName, r := range a.Tasks {
		lc := a.TaskLifecycles[taskName]
		if lc == nil {
			main.Add(r)
		} else if lc.Hook == TaskLifecycleHookPrestart {
			if lc.Sidecar {
				prestartSidecarTasks.Add(r)
			} else {
				prestartEphemeralTasks.Add(r)
			}
		} else if lc.Hook == TaskLifecycleHookPoststop {
			poststopTasks.Add(r)
		}
	}

	// update this loop to account for lifecycle hook
	prestartEphemeralTasks.Max(main)
	prestartEphemeralTasks.Max(poststopTasks)
	prestartSidecarTasks.Add(prestartEphemeralTasks)
	c.Flattened.Add(prestartSidecarTasks)

	// Add network resources that are at the task group level
	for _, network := range a.Shared.Networks {
		c.Flattened.Add(&AllocatedTaskResources{
			Networks: []*NetworkResource{network},
		})
	}

	return c
}

// OldTaskResources returns the pre-0.9.0 map of task resources
func (a *AllocatedResources) OldTaskResources() map[string]*Resources {
	m := make(map[string]*Resources, len(a.Tasks))
	for name, res := range a.Tasks {
		m[name] = &Resources{
			CPU:      int(res.Cpu.CpuShares),
			MemoryMB: int(res.Memory.MemoryMB),
			Networks: res.Networks,
		}
	}

	return m
}

func (a *AllocatedResources) Canonicalize() {
	a.Shared.Canonicalize()

	for _, r := range a.Tasks {
		for _, nw := range r.Networks {
			for _, port := range append(nw.DynamicPorts, nw.ReservedPorts...) {
				a.Shared.Ports = append(a.Shared.Ports, AllocatedPortMapping{
					Label:  port.Label,
					Value:  port.Value,
					To:     port.To,
					HostIP: nw.IP,
				})
			}
		}
	}
}

// AllocatedTaskResources are the set of resources allocated to a task.
type AllocatedTaskResources struct {
	Cpu      AllocatedCpuResources
	Memory   AllocatedMemoryResources
	Networks Networks
	Devices  []*AllocatedDeviceResource
}

func (a *AllocatedTaskResources) Copy() *AllocatedTaskResources {
	if a == nil {
		return nil
	}
	newA := new(AllocatedTaskResources)
	*newA = *a

	// Copy the networks
	newA.Networks = a.Networks.Copy()

	// Copy the devices
	if newA.Devices != nil {
		n := len(a.Devices)
		newA.Devices = make([]*AllocatedDeviceResource, n)
		for i := 0; i < n; i++ {
			newA.Devices[i] = a.Devices[i].Copy()
		}
	}

	return newA
}

// NetIndex finds the matching net index using device name
func (a *AllocatedTaskResources) NetIndex(n *NetworkResource) int {
	return a.Networks.NetIndex(n)
}

func (a *AllocatedTaskResources) Add(delta *AllocatedTaskResources) {
	if delta == nil {
		return
	}

	a.Cpu.Add(&delta.Cpu)
	a.Memory.Add(&delta.Memory)

	for _, n := range delta.Networks {
		// Find the matching interface by IP or CIDR
		idx := a.NetIndex(n)
		if idx == -1 {
			a.Networks = append(a.Networks, n.Copy())
		} else {
			a.Networks[idx].Add(n)
		}
	}

	for _, d := range delta.Devices {
		// Find the matching device
		idx := AllocatedDevices(a.Devices).Index(d)
		if idx == -1 {
			a.Devices = append(a.Devices, d.Copy())
		} else {
			a.Devices[idx].Add(d)
		}
	}
}

func (a *AllocatedTaskResources) Max(other *AllocatedTaskResources) {
	if other == nil {
		return
	}

	a.Cpu.Max(&other.Cpu)
	a.Memory.Max(&other.Memory)

	for _, n := range other.Networks {
		// Find the matching interface by IP or CIDR
		idx := a.NetIndex(n)
		if idx == -1 {
			a.Networks = append(a.Networks, n.Copy())
		} else {
			a.Networks[idx].Add(n)
		}
	}

	for _, d := range other.Devices {
		// Find the matching device
		idx := AllocatedDevices(a.Devices).Index(d)
		if idx == -1 {
			a.Devices = append(a.Devices, d.Copy())
		} else {
			a.Devices[idx].Add(d)
		}
	}
}

// Comparable turns AllocatedTaskResources into ComparableResources
// as a helper step in preemption
func (a *AllocatedTaskResources) Comparable() *ComparableResources {
	ret := &ComparableResources{
		Flattened: AllocatedTaskResources{
			Cpu: AllocatedCpuResources{
				CpuShares: a.Cpu.CpuShares,
			},
			Memory: AllocatedMemoryResources{
				MemoryMB: a.Memory.MemoryMB,
			},
		},
	}
	ret.Flattened.Networks = append(ret.Flattened.Networks, a.Networks...)
	return ret
}

// Subtract only subtracts CPU and Memory resources. Network utilization
// is managed separately in NetworkIndex
func (a *AllocatedTaskResources) Subtract(delta *AllocatedTaskResources) {
	if delta == nil {
		return
	}

	a.Cpu.Subtract(&delta.Cpu)
	a.Memory.Subtract(&delta.Memory)
}

// AllocatedSharedResources are the set of resources allocated to a task group.
type AllocatedSharedResources struct {
	Networks Networks
	DiskMB   int64
	Ports    AllocatedPorts
}

func (a AllocatedSharedResources) Copy() AllocatedSharedResources {
	return AllocatedSharedResources{
		Networks: a.Networks.Copy(),
		DiskMB:   a.DiskMB,
		Ports:    a.Ports,
	}
}

func (a *AllocatedSharedResources) Add(delta *AllocatedSharedResources) {
	if delta == nil {
		return
	}
	a.Networks = append(a.Networks, delta.Networks...)
	a.DiskMB += delta.DiskMB

}

func (a *AllocatedSharedResources) Subtract(delta *AllocatedSharedResources) {
	if delta == nil {
		return
	}

	diff := map[*NetworkResource]bool{}
	for _, n := range delta.Networks {
		diff[n] = true
	}
	var nets Networks
	for _, n := range a.Networks {
		if _, ok := diff[n]; !ok {
			nets = append(nets, n)
		}
	}
	a.Networks = nets
	a.DiskMB -= delta.DiskMB
}

func (a *AllocatedSharedResources) Canonicalize() {
	if len(a.Networks) > 0 {
		if len(a.Networks[0].DynamicPorts)+len(a.Networks[0].ReservedPorts) > 0 && len(a.Ports) == 0 {
			for _, ports := range [][]Port{a.Networks[0].DynamicPorts, a.Networks[0].ReservedPorts} {
				for _, p := range ports {
					a.Ports = append(a.Ports, AllocatedPortMapping{
						Label:  p.Label,
						Value:  p.Value,
						To:     p.To,
						HostIP: a.Networks[0].IP,
					})
				}
			}
		}
	}
}

// AllocatedCpuResources captures the allocated CPU resources.
type AllocatedCpuResources struct {
	CpuShares int64
}

func (a *AllocatedCpuResources) Add(delta *AllocatedCpuResources) {
	if delta == nil {
		return
	}

	a.CpuShares += delta.CpuShares
}

func (a *AllocatedCpuResources) Subtract(delta *AllocatedCpuResources) {
	if delta == nil {
		return
	}

	a.CpuShares -= delta.CpuShares
}

func (a *AllocatedCpuResources) Max(other *AllocatedCpuResources) {
	if other == nil {
		return
	}

	if other.CpuShares > a.CpuShares {
		a.CpuShares = other.CpuShares
	}
}

// AllocatedMemoryResources captures the allocated memory resources.
type AllocatedMemoryResources struct {
	MemoryMB int64
}

func (a *AllocatedMemoryResources) Add(delta *AllocatedMemoryResources) {
	if delta == nil {
		return
	}

	a.MemoryMB += delta.MemoryMB
}

func (a *AllocatedMemoryResources) Subtract(delta *AllocatedMemoryResources) {
	if delta == nil {
		return
	}

	a.MemoryMB -= delta.MemoryMB
}

func (a *AllocatedMemoryResources) Max(other *AllocatedMemoryResources) {
	if other == nil {
		return
	}

	if other.MemoryMB > a.MemoryMB {
		a.MemoryMB = other.MemoryMB
	}
}

type AllocatedDevices []*AllocatedDeviceResource

// Index finds the matching index using the passed device. If not found, -1 is
// returned.
func (a AllocatedDevices) Index(d *AllocatedDeviceResource) int {
	if d == nil {
		return -1
	}

	for i, o := range a {
		if o.ID().Equals(d.ID()) {
			return i
		}
	}

	return -1
}

// AllocatedDeviceResource captures a set of allocated devices.
type AllocatedDeviceResource struct {
	// Vendor, Type, and Name are used to select the plugin to request the
	// device IDs from.
	Vendor string
	Type   string
	Name   string

	// DeviceIDs is the set of allocated devices
	DeviceIDs []string
}

func (a *AllocatedDeviceResource) ID() *DeviceIdTuple {
	if a == nil {
		return nil
	}

	return &DeviceIdTuple{
		Vendor: a.Vendor,
		Type:   a.Type,
		Name:   a.Name,
	}
}

func (a *AllocatedDeviceResource) Add(delta *AllocatedDeviceResource) {
	if delta == nil {
		return
	}

	a.DeviceIDs = append(a.DeviceIDs, delta.DeviceIDs...)
}

func (a *AllocatedDeviceResource) Copy() *AllocatedDeviceResource {
	if a == nil {
		return a
	}

	na := *a

	// Copy the devices
	na.DeviceIDs = make([]string, len(a.DeviceIDs))
	for i, id := range a.DeviceIDs {
		na.DeviceIDs[i] = id
	}

	return &na
}

// ComparableResources is the set of resources allocated to a task group but
// not keyed by Task, making it easier to compare.
type ComparableResources struct {
	Flattened AllocatedTaskResources
	Shared    AllocatedSharedResources
}

func (c *ComparableResources) Add(delta *ComparableResources) {
	if delta == nil {
		return
	}

	c.Flattened.Add(&delta.Flattened)
	c.Shared.Add(&delta.Shared)
}

func (c *ComparableResources) Subtract(delta *ComparableResources) {
	if delta == nil {
		return
	}

	c.Flattened.Subtract(&delta.Flattened)
	c.Shared.Subtract(&delta.Shared)
}

func (c *ComparableResources) Copy() *ComparableResources {
	if c == nil {
		return nil
	}
	newR := new(ComparableResources)
	*newR = *c
	return newR
}

// Superset checks if one set of resources is a superset of another. This
// ignores network resources, and the NetworkIndex should be used for that.
func (c *ComparableResources) Superset(other *ComparableResources) (bool, string) {
	if c.Flattened.Cpu.CpuShares < other.Flattened.Cpu.CpuShares {
		return false, "cpu"
	}
	if c.Flattened.Memory.MemoryMB < other.Flattened.Memory.MemoryMB {
		return false, "memory"
	}
	if c.Shared.DiskMB < other.Shared.DiskMB {
		return false, "disk"
	}
	return true, ""
}

// allocated finds the matching net index using device name
func (c *ComparableResources) NetIndex(n *NetworkResource) int {
	return c.Flattened.Networks.NetIndex(n)
}

const (
	// JobTypeNomad is reserved for internal system tasks and is
	// always handled by the CoreScheduler.
	JobTypeCore    = "_core"
	JobTypeService = "service"
	JobTypeBatch   = "batch"
	JobTypeSystem  = "system"
)

const (
	JobStatusPending = "pending" // Pending means the job is waiting on scheduling
	JobStatusRunning = "running" // Running means the job has non-terminal allocations
	JobStatusDead    = "dead"    // Dead means all evaluation's and allocations are terminal
)

const (
	// JobMinPriority is the minimum allowed priority
	JobMinPriority = 1

	// JobDefaultPriority is the default priority if not
	// not specified.
	JobDefaultPriority = 50

	// JobMaxPriority is the maximum allowed priority
	JobMaxPriority = 100

	// Ensure CoreJobPriority is higher than any user
	// specified job so that it gets priority. This is important
	// for the system to remain healthy.
	CoreJobPriority = JobMaxPriority * 2

	// JobTrackedVersions is the number of historic job versions that are
	// kept.
	JobTrackedVersions = 6

	// JobTrackedScalingEvents is the number of scaling events that are
	// kept for a single task group.
	JobTrackedScalingEvents = 20
)

// Job is the scope of a scheduling request to Nomad. It is the largest
// scoped object, and is a named collection of task groups. Each task group
// is further composed of tasks. A task group (TG) is the unit of scheduling
// however.
type Job struct {
	// Stop marks whether the user has stopped the job. A stopped job will
	// have all created allocations stopped and acts as a way to stop a job
	// without purging it from the system. This allows existing allocs to be
	// queried and the job to be inspected as it is being killed.
	Stop bool

	// Region is the Nomad region that handles scheduling this job
	Region string

	// Namespace is the namespace the job is submitted into.
	Namespace string

	// ID is a unique identifier for the job per region. It can be
	// specified hierarchically like LineOfBiz/OrgName/Team/Project
	ID string

	// ParentID is the unique identifier of the job that spawned this job.
	ParentID string

	// Name is the logical name of the job used to refer to it. This is unique
	// per region, but not unique globally.
	Name string

	// Type is used to control various behaviors about the job. Most jobs
	// are service jobs, meaning they are expected to be long lived.
	// Some jobs are batch oriented meaning they run and then terminate.
	// This can be extended in the future to support custom schedulers.
	Type string

	// Priority is used to control scheduling importance and if this job
	// can preempt other jobs.
	Priority int

	// AllAtOnce is used to control if incremental scheduling of task groups
	// is allowed or if we must do a gang scheduling of the entire job. This
	// can slow down larger jobs if resources are not available.
	AllAtOnce bool

	// Datacenters contains all the datacenters this job is allowed to span
	Datacenters []string

	// Constraints can be specified at a job level and apply to
	// all the task groups and tasks.
	Constraints []*Constraint

	// Affinities can be specified at the job level to express
	// scheduling preferences that apply to all groups and tasks
	Affinities []*Affinity

	// Spread can be specified at the job level to express spreading
	// allocations across a desired attribute, such as datacenter
	Spreads []*Spread

	// TaskGroups are the collections of task groups that this job needs
	// to run. Each task group is an atomic unit of scheduling and placement.
	TaskGroups []*TaskGroup

	// See agent.ApiJobToStructJob
	// Update provides defaults for the TaskGroup Update stanzas
	Update UpdateStrategy

	Multiregion *Multiregion

	// Periodic is used to define the interval the job is run at.
	Periodic *PeriodicConfig

	// ParameterizedJob is used to specify the job as a parameterized job
	// for dispatching.
	ParameterizedJob *ParameterizedJobConfig

	// Dispatched is used to identify if the Job has been dispatched from a
	// parameterized job.
	Dispatched bool

	// Payload is the payload supplied when the job was dispatched.
	Payload []byte

	// Meta is used to associate arbitrary metadata with this
	// job. This is opaque to Nomad.
	Meta map[string]string

	// ConsulToken is the Consul token that proves the submitter of the job has
	// access to the Service Identity policies associated with the job's
	// Consul Connect enabled services. This field is only used to transfer the
	// token and is not stored after Job submission.
	ConsulToken string

	// VaultToken is the Vault token that proves the submitter of the job has
	// access to the specified Vault policies. This field is only used to
	// transfer the token and is not stored after Job submission.
	VaultToken string

	// VaultNamespace is the Vault namepace
	VaultNamespace string

	// NomadTokenID is the Accessor ID of the ACL token (if any)
	// used to register this version of the job. Used by deploymentwatcher.
	NomadTokenID string

	// Job status
	Status string

	// StatusDescription is meant to provide more human useful information
	StatusDescription string

	// Stable marks a job as stable. Stability is only defined on "service" and
	// "system" jobs. The stability of a job will be set automatically as part
	// of a deployment and can be manually set via APIs. This field is updated
	// when the status of a corresponding deployment transitions to Failed
	// or Successful. This field is not meaningful for jobs that don't have an
	// update stanza.
	Stable bool

	// Version is a monotonically increasing version number that is incremented
	// on each job register.
	Version uint64

	// SubmitTime is the time at which the job was submitted as a UnixNano in
	// UTC
	SubmitTime int64

	// Raft Indexes
	CreateIndex    uint64
	ModifyIndex    uint64
	JobModifyIndex uint64
}

// NamespacedID returns the namespaced id useful for logging
func (j *Job) NamespacedID() *NamespacedID {
	return &NamespacedID{
		ID:        j.ID,
		Namespace: j.Namespace,
	}
}

// Canonicalize is used to canonicalize fields in the Job. This should be
// called when registering a Job.
func (j *Job) Canonicalize() {
	if j == nil {
		return
	}

	// Ensure that an empty and nil map are treated the same to avoid scheduling
	// problems since we use reflect DeepEquals.
	if len(j.Meta) == 0 {
		j.Meta = nil
	}

	// Ensure the job is in a namespace.
	if j.Namespace == "" {
		j.Namespace = DefaultNamespace
	}

	for _, tg := range j.TaskGroups {
		tg.Canonicalize(j)
	}

	if j.ParameterizedJob != nil {
		j.ParameterizedJob.Canonicalize()
	}

	if j.Multiregion != nil {
		j.Multiregion.Canonicalize()
	}

	if j.Periodic != nil {
		j.Periodic.Canonicalize()
	}
}

// Copy returns a deep copy of the Job. It is expected that callers use recover.
// This job can panic if the deep copy failed as it uses reflection.
func (j *Job) Copy() *Job {
	if j == nil {
		return nil
	}
	nj := new(Job)
	*nj = *j
	nj.Datacenters = helper.CopySliceString(nj.Datacenters)
	nj.Constraints = CopySliceConstraints(nj.Constraints)
	nj.Affinities = CopySliceAffinities(nj.Affinities)
	nj.Multiregion = nj.Multiregion.Copy()

	if j.TaskGroups != nil {
		tgs := make([]*TaskGroup, len(nj.TaskGroups))
		for i, tg := range nj.TaskGroups {
			tgs[i] = tg.Copy()
		}
		nj.TaskGroups = tgs
	}

	nj.Periodic = nj.Periodic.Copy()
	nj.Meta = helper.CopyMapStringString(nj.Meta)
	nj.ParameterizedJob = nj.ParameterizedJob.Copy()
	return nj
}

// Validate is used to sanity check a job input
func (j *Job) Validate() error {
	var mErr multierror.Error

	if j.Region == "" && j.Multiregion == nil {
		mErr.Errors = append(mErr.Errors, errors.New("Missing job region"))
	}
	if j.ID == "" {
		mErr.Errors = append(mErr.Errors, errors.New("Missing job ID"))
	} else if strings.Contains(j.ID, " ") {
		mErr.Errors = append(mErr.Errors, errors.New("Job ID contains a space"))
	} else if strings.Contains(j.ID, "\000") {
		mErr.Errors = append(mErr.Errors, errors.New("Job ID contains a null character"))
	}
	if j.Name == "" {
		mErr.Errors = append(mErr.Errors, errors.New("Missing job name"))
	} else if strings.Contains(j.Name, "\000") {
		mErr.Errors = append(mErr.Errors, errors.New("Job Name contains a null character"))
	}
	if j.Namespace == "" {
		mErr.Errors = append(mErr.Errors, errors.New("Job must be in a namespace"))
	}
	switch j.Type {
	case JobTypeCore, JobTypeService, JobTypeBatch, JobTypeSystem:
	case "":
		mErr.Errors = append(mErr.Errors, errors.New("Missing job type"))
	default:
		mErr.Errors = append(mErr.Errors, fmt.Errorf("Invalid job type: %q", j.Type))
	}
	if j.Priority < JobMinPriority || j.Priority > JobMaxPriority {
		mErr.Errors = append(mErr.Errors, fmt.Errorf("Job priority must be between [%d, %d]", JobMinPriority, JobMaxPriority))
	}
	if len(j.Datacenters) == 0 && !j.IsMultiregion() {
		mErr.Errors = append(mErr.Errors, errors.New("Missing job datacenters"))
	} else {
		for _, v := range j.Datacenters {
			if v == "" {
				mErr.Errors = append(mErr.Errors, errors.New("Job datacenter must be non-empty string"))
			}
		}
	}
	if len(j.TaskGroups) == 0 {
		mErr.Errors = append(mErr.Errors, errors.New("Missing job task groups"))
	}
	for idx, constr := range j.Constraints {
		if err := constr.Validate(); err != nil {
			outer := fmt.Errorf("Constraint %d validation failed: %s", idx+1, err)
			mErr.Errors = append(mErr.Errors, outer)
		}
	}
	if j.Type == JobTypeSystem {
		if j.Affinities != nil {
			mErr.Errors = append(mErr.Errors, fmt.Errorf("System jobs may not have an affinity stanza"))
		}
	} else {
		for idx, affinity := range j.Affinities {
			if err := affinity.Validate(); err != nil {
				outer := fmt.Errorf("Affinity %d validation failed: %s", idx+1, err)
				mErr.Errors = append(mErr.Errors, outer)
			}
		}
	}

	if j.Type == JobTypeSystem {
		if j.Spreads != nil {
			mErr.Errors = append(mErr.Errors, fmt.Errorf("System jobs may not have a spread stanza"))
		}
	} else {
		for idx, spread := range j.Spreads {
			if err := spread.Validate(); err != nil {
				outer := fmt.Errorf("Spread %d validation failed: %s", idx+1, err)
				mErr.Errors = append(mErr.Errors, outer)
			}
		}
	}

	// Check for duplicate task groups
	taskGroups := make(map[string]int)
	for idx, tg := range j.TaskGroups {
		if tg.Name == "" {
			mErr.Errors = append(mErr.Errors, fmt.Errorf("Job task group %d missing name", idx+1))
		} else if existing, ok := taskGroups[tg.Name]; ok {
			mErr.Errors = append(mErr.Errors, fmt.Errorf("Job task group %d redefines '%s' from group %d", idx+1, tg.Name, existing+1))
		} else {
			taskGroups[tg.Name] = idx
		}

		if tg.ShutdownDelay != nil && *tg.ShutdownDelay < 0 {
			mErr.Errors = append(mErr.Errors, errors.New("ShutdownDelay must be a positive value"))
		}

		if tg.StopAfterClientDisconnect != nil && *tg.StopAfterClientDisconnect != 0 {
			if *tg.StopAfterClientDisconnect > 0 &&
				!(j.Type == JobTypeBatch || j.Type == JobTypeService) {
				mErr.Errors = append(mErr.Errors, errors.New("stop_after_client_disconnect can only be set in batch and service jobs"))
			} else if *tg.StopAfterClientDisconnect < 0 {
				mErr.Errors = append(mErr.Errors, errors.New("stop_after_client_disconnect must be a positive value"))
			}
		}

		if j.Type == "system" && tg.Count > 1 {
			mErr.Errors = append(mErr.Errors,
				fmt.Errorf("Job task group %s has count %d. Count cannot exceed 1 with system scheduler",
					tg.Name, tg.Count))
		}
	}

	// Validate the task group
	for _, tg := range j.TaskGroups {
		if err := tg.Validate(j); err != nil {
			outer := fmt.Errorf("Task group %s validation failed: %v", tg.Name, err)
			mErr.Errors = append(mErr.Errors, outer)
		}
	}

	// Validate periodic is only used with batch jobs.
	if j.IsPeriodic() && j.Periodic.Enabled {
		if j.Type != JobTypeBatch {
			mErr.Errors = append(mErr.Errors,
				fmt.Errorf("Periodic can only be used with %q scheduler", JobTypeBatch))
		}

		if err := j.Periodic.Validate(); err != nil {
			mErr.Errors = append(mErr.Errors, err)
		}
	}

	if j.IsParameterized() {
		if j.Type != JobTypeBatch {
			mErr.Errors = append(mErr.Errors,
				fmt.Errorf("Parameterized job can only be used with %q scheduler", JobTypeBatch))
		}

		if err := j.ParameterizedJob.Validate(); err != nil {
			mErr.Errors = append(mErr.Errors, err)
		}
	}

	if j.IsMultiregion() {
		if err := j.Multiregion.Validate(j.Type, j.Datacenters); err != nil {
			mErr.Errors = append(mErr.Errors, err)
		}
	}

	return mErr.ErrorOrNil()
}

// Warnings returns a list of warnings that may be from dubious settings or
// deprecation warnings.
func (j *Job) Warnings() error {
	var mErr multierror.Error

	// Check the groups
	ap := 0
	for _, tg := range j.TaskGroups {
		if err := tg.Warnings(j); err != nil {
			outer := fmt.Errorf("Group %q has warnings: %v", tg.Name, err)
			mErr.Errors = append(mErr.Errors, outer)
		}
		if tg.Update != nil && tg.Update.AutoPromote {
			ap += 1
		}
	}

	// Check AutoPromote, should be all or none
	if ap > 0 && ap < len(j.TaskGroups) {
		err := fmt.Errorf("auto_promote must be true for all groups to enable automatic promotion")
		mErr.Errors = append(mErr.Errors, err)
	}

	return mErr.ErrorOrNil()
}

// LookupTaskGroup finds a task group by name
func (j *Job) LookupTaskGroup(name string) *TaskGroup {
	for _, tg := range j.TaskGroups {
		if tg.Name == name {
			return tg
		}
	}
	return nil
}

// CombinedTaskMeta takes a TaskGroup and Task name and returns the combined
// meta data for the task. When joining Job, Group and Task Meta, the precedence
// is by deepest scope (Task > Group > Job).
func (j *Job) CombinedTaskMeta(groupName, taskName string) map[string]string {
	group := j.LookupTaskGroup(groupName)
	if group == nil {
		return j.Meta
	}

	var meta map[string]string

	task := group.LookupTask(taskName)
	if task != nil {
		meta = helper.CopyMapStringString(task.Meta)
	}

	if meta == nil {
		meta = make(map[string]string, len(group.Meta)+len(j.Meta))
	}

	// Add the group specific meta
	for k, v := range group.Meta {
		if _, ok := meta[k]; !ok {
			meta[k] = v
		}
	}

	// Add the job specific meta
	for k, v := range j.Meta {
		if _, ok := meta[k]; !ok {
			meta[k] = v
		}
	}

	return meta
}

// Stopped returns if a job is stopped.
func (j *Job) Stopped() bool {
	return j == nil || j.Stop
}

// HasUpdateStrategy returns if any task group in the job has an update strategy
func (j *Job) HasUpdateStrategy() bool {
	for _, tg := range j.TaskGroups {
		if !tg.Update.IsEmpty() {
			return true
		}
	}

	return false
}

// Stub is used to return a summary of the job
func (j *Job) Stub(summary *JobSummary) *JobListStub {
	return &JobListStub{
		ID:                j.ID,
		ParentID:          j.ParentID,
		Name:              j.Name,
		Datacenters:       j.Datacenters,
		Multiregion:       j.Multiregion,
		Type:              j.Type,
		Priority:          j.Priority,
		Periodic:          j.IsPeriodic(),
		ParameterizedJob:  j.IsParameterized(),
		Stop:              j.Stop,
		Status:            j.Status,
		StatusDescription: j.StatusDescription,
		CreateIndex:       j.CreateIndex,
		ModifyIndex:       j.ModifyIndex,
		JobModifyIndex:    j.JobModifyIndex,
		SubmitTime:        j.SubmitTime,
		JobSummary:        summary,
	}
}

// IsPeriodic returns whether a job is periodic.
func (j *Job) IsPeriodic() bool {
	return j.Periodic != nil
}

// IsPeriodicActive returns whether the job is an active periodic job that will
// create child jobs
func (j *Job) IsPeriodicActive() bool {
	return j.IsPeriodic() && j.Periodic.Enabled && !j.Stopped() && !j.IsParameterized()
}

// IsParameterized returns whether a job is parameterized job.
func (j *Job) IsParameterized() bool {
	return j.ParameterizedJob != nil && !j.Dispatched
}

// IsMultiregion returns whether a job is multiregion
func (j *Job) IsMultiregion() bool {
	return j.Multiregion != nil && j.Multiregion.Regions != nil && len(j.Multiregion.Regions) > 0
}

// VaultPolicies returns the set of Vault policies per task group, per task
func (j *Job) VaultPolicies() map[string]map[string]*Vault {
	policies := make(map[string]map[string]*Vault, len(j.TaskGroups))

	for _, tg := range j.TaskGroups {
		tgPolicies := make(map[string]*Vault, len(tg.Tasks))

		for _, task := range tg.Tasks {
			if task.Vault == nil {
				continue
			}

			tgPolicies[task.Name] = task.Vault
		}

		if len(tgPolicies) != 0 {
			policies[tg.Name] = tgPolicies
		}
	}

	return policies
}

// ConnectTasks returns the set of Consul Connect enabled tasks defined on the
// job that will require a Service Identity token in the case that Consul ACLs
// are enabled. The TaskKind.Value is the name of the Consul service.
//
// This method is meaningful only after the Job has passed through the job
// submission Mutator functions.
func (j *Job) ConnectTasks() []TaskKind {
	var kinds []TaskKind
	for _, tg := range j.TaskGroups {
		for _, task := range tg.Tasks {
			if task.Kind.IsConnectProxy() ||
				task.Kind.IsConnectNative() ||
				task.Kind.IsAnyConnectGateway() {
				kinds = append(kinds, task.Kind)
			}
		}
	}
	return kinds
}

// RequiredSignals returns a mapping of task groups to tasks to their required
// set of signals
func (j *Job) RequiredSignals() map[string]map[string][]string {
	signals := make(map[string]map[string][]string)

	for _, tg := range j.TaskGroups {
		for _, task := range tg.Tasks {
			// Use this local one as a set
			taskSignals := make(map[string]struct{})

			// Check if the Vault change mode uses signals
			if task.Vault != nil && task.Vault.ChangeMode == VaultChangeModeSignal {
				taskSignals[task.Vault.ChangeSignal] = struct{}{}
			}

			// If a user has specified a KillSignal, add it to required signals
			if task.KillSignal != "" {
				taskSignals[task.KillSignal] = struct{}{}
			}

			// Check if any template change mode uses signals
			for _, t := range task.Templates {
				if t.ChangeMode != TemplateChangeModeSignal {
					continue
				}

				taskSignals[t.ChangeSignal] = struct{}{}
			}

			// Flatten and sort the signals
			l := len(taskSignals)
			if l == 0 {
				continue
			}

			flat := make([]string, 0, l)
			for sig := range taskSignals {
				flat = append(flat, sig)
			}

			sort.Strings(flat)
			tgSignals, ok := signals[tg.Name]
			if !ok {
				tgSignals = make(map[string][]string)
				signals[tg.Name] = tgSignals
			}
			tgSignals[task.Name] = flat
		}

	}

	return signals
}

// SpecChanged determines if the functional specification has changed between
// two job versions.
func (j *Job) SpecChanged(new *Job) bool {
	if j == nil {
		return new != nil
	}

	// Create a copy of the new job
	c := new.Copy()

	// Update the new job so we can do a reflect
	c.Status = j.Status
	c.StatusDescription = j.StatusDescription
	c.Stable = j.Stable
	c.Version = j.Version
	c.CreateIndex = j.CreateIndex
	c.ModifyIndex = j.ModifyIndex
	c.JobModifyIndex = j.JobModifyIndex
	c.SubmitTime = j.SubmitTime

	// cgbaker: FINISH: probably need some consideration of scaling policy ID here

	// Deep equals the jobs
	return !reflect.DeepEqual(j, c)
}

func (j *Job) SetSubmitTime() {
	j.SubmitTime = time.Now().UTC().UnixNano()
}

// JobListStub is used to return a subset of job information
// for the job list
type JobListStub struct {
	ID                string
	ParentID          string
	Name              string
	Namespace         string `json:",omitempty"`
	Datacenters       []string
	Multiregion       *Multiregion
	Type              string
	Priority          int
	Periodic          bool
	ParameterizedJob  bool
	Stop              bool
	Status            string
	StatusDescription string
	JobSummary        *JobSummary
	CreateIndex       uint64
	ModifyIndex       uint64
	JobModifyIndex    uint64
	SubmitTime        int64
}

// JobSummary summarizes the state of the allocations of a job
type JobSummary struct {
	// JobID is the ID of the job the summary is for
	JobID string

	// Namespace is the namespace of the job and its summary
	Namespace string

	// Summary contains the summary per task group for the Job
	Summary map[string]TaskGroupSummary

	// Children contains a summary for the children of this job.
	Children *JobChildrenSummary

	// Raft Indexes
	CreateIndex uint64
	ModifyIndex uint64
}

// Copy returns a new copy of JobSummary
func (js *JobSummary) Copy() *JobSummary {
	newJobSummary := new(JobSummary)
	*newJobSummary = *js
	newTGSummary := make(map[string]TaskGroupSummary, len(js.Summary))
	for k, v := range js.Summary {
		newTGSummary[k] = v
	}
	newJobSummary.Summary = newTGSummary
	newJobSummary.Children = newJobSummary.Children.Copy()
	return newJobSummary
}

// JobChildrenSummary contains the summary of children job statuses
type JobChildrenSummary struct {
	Pending int64
	Running int64
	Dead    int64
}

// Copy returns a new copy of a JobChildrenSummary
func (jc *JobChildrenSummary) Copy() *JobChildrenSummary {
	if jc == nil {
		return nil
	}

	njc := new(JobChildrenSummary)
	*njc = *jc
	return njc
}

// TaskGroup summarizes the state of all the allocations of a particular
// TaskGroup
type TaskGroupSummary struct {
	Queued   int
	Complete int
	Failed   int
	Running  int
	Starting int
	Lost     int
}

const (
	// Checks uses any registered health check state in combination with task
	// states to determine if a allocation is healthy.
	UpdateStrategyHealthCheck_Checks = "checks"

	// TaskStates uses the task states of an allocation to determine if the
	// allocation is healthy.
	UpdateStrategyHealthCheck_TaskStates = "task_states"

	// Manual allows the operator to manually signal to Nomad when an
	// allocations is healthy. This allows more advanced health checking that is
	// outside of the scope of Nomad.
	UpdateStrategyHealthCheck_Manual = "manual"
)

var (
	// DefaultUpdateStrategy provides a baseline that can be used to upgrade
	// jobs with the old policy or for populating field defaults.
	DefaultUpdateStrategy = &UpdateStrategy{
		Stagger:          30 * time.Second,
		MaxParallel:      1,
		HealthCheck:      UpdateStrategyHealthCheck_Checks,
		MinHealthyTime:   10 * time.Second,
		HealthyDeadline:  5 * time.Minute,
		ProgressDeadline: 10 * time.Minute,
		AutoRevert:       false,
		AutoPromote:      false,
		Canary:           0,
	}
)

// UpdateStrategy is used to modify how updates are done
type UpdateStrategy struct {
	// Stagger is used to determine the rate at which allocations are migrated
	// due to down or draining nodes.
	Stagger time.Duration

	// MaxParallel is how many updates can be done in parallel
	MaxParallel int

	// HealthCheck specifies the mechanism in which allocations are marked
	// healthy or unhealthy as part of a deployment.
	HealthCheck string

	// MinHealthyTime is the minimum time an allocation must be in the healthy
	// state before it is marked as healthy, unblocking more allocations to be
	// rolled.
	MinHealthyTime time.Duration

	// HealthyDeadline is the time in which an allocation must be marked as
	// healthy before it is automatically transitioned to unhealthy. This time
	// period doesn't count against the MinHealthyTime.
	HealthyDeadline time.Duration

	// ProgressDeadline is the time in which an allocation as part of the
	// deployment must transition to healthy. If no allocation becomes healthy
	// after the deadline, the deployment is marked as failed. If the deadline
	// is zero, the first failure causes the deployment to fail.
	ProgressDeadline time.Duration

	// AutoRevert declares that if a deployment fails because of unhealthy
	// allocations, there should be an attempt to auto-revert the job to a
	// stable version.
	AutoRevert bool

	// AutoPromote declares that the deployment should be promoted when all canaries are
	// healthy
	AutoPromote bool

	// Canary is the number of canaries to deploy when a change to the task
	// group is detected.
	Canary int
}

func (u *UpdateStrategy) Copy() *UpdateStrategy {
	if u == nil {
		return nil
	}

	copy := new(UpdateStrategy)
	*copy = *u
	return copy
}

func (u *UpdateStrategy) Validate() error {
	if u == nil {
		return nil
	}

	var mErr multierror.Error
	switch u.HealthCheck {
	case UpdateStrategyHealthCheck_Checks, UpdateStrategyHealthCheck_TaskStates, UpdateStrategyHealthCheck_Manual:
	default:
		_ = multierror.Append(&mErr, fmt.Errorf("Invalid health check given: %q", u.HealthCheck))
	}

	if u.MaxParallel < 0 {
		_ = multierror.Append(&mErr, fmt.Errorf("Max parallel can not be less than zero: %d < 0", u.MaxParallel))
	}
	if u.Canary < 0 {
		_ = multierror.Append(&mErr, fmt.Errorf("Canary count can not be less than zero: %d < 0", u.Canary))
	}
	if u.Canary == 0 && u.AutoPromote {
		_ = multierror.Append(&mErr, fmt.Errorf("Auto Promote requires a Canary count greater than zero"))
	}
	if u.MinHealthyTime < 0 {
		_ = multierror.Append(&mErr, fmt.Errorf("Minimum healthy time may not be less than zero: %v", u.MinHealthyTime))
	}
	if u.HealthyDeadline <= 0 {
		_ = multierror.Append(&mErr, fmt.Errorf("Healthy deadline must be greater than zero: %v", u.HealthyDeadline))
	}
	if u.ProgressDeadline < 0 {
		_ = multierror.Append(&mErr, fmt.Errorf("Progress deadline must be zero or greater: %v", u.ProgressDeadline))
	}
	if u.MinHealthyTime >= u.HealthyDeadline {
		_ = multierror.Append(&mErr, fmt.Errorf("Minimum healthy time must be less than healthy deadline: %v > %v", u.MinHealthyTime, u.HealthyDeadline))
	}
	if u.ProgressDeadline != 0 && u.HealthyDeadline >= u.ProgressDeadline {
		_ = multierror.Append(&mErr, fmt.Errorf("Healthy deadline must be less than progress deadline: %v > %v", u.HealthyDeadline, u.ProgressDeadline))
	}
	if u.Stagger <= 0 {
		_ = multierror.Append(&mErr, fmt.Errorf("Stagger must be greater than zero: %v", u.Stagger))
	}

	return mErr.ErrorOrNil()
}

func (u *UpdateStrategy) IsEmpty() bool {
	if u == nil {
		return true
	}

	return u.MaxParallel == 0
}

// TODO(alexdadgar): Remove once no longer used by the scheduler.
// Rolling returns if a rolling strategy should be used
func (u *UpdateStrategy) Rolling() bool {
	return u.Stagger > 0 && u.MaxParallel > 0
}

type Multiregion struct {
	Strategy *MultiregionStrategy
	Regions  []*MultiregionRegion
}

func (m *Multiregion) Canonicalize() {
	if m.Strategy == nil {
		m.Strategy = &MultiregionStrategy{}
	}
	if m.Regions == nil {
		m.Regions = []*MultiregionRegion{}
	}
}

// Diff indicates whether the multiregion config has changed
func (m *Multiregion) Diff(m2 *Multiregion) bool {
	return !reflect.DeepEqual(m, m2)
}

func (m *Multiregion) Copy() *Multiregion {
	if m == nil {
		return nil
	}
	copy := new(Multiregion)
	if m.Strategy != nil {
		copy.Strategy = &MultiregionStrategy{
			MaxParallel: m.Strategy.MaxParallel,
			OnFailure:   m.Strategy.OnFailure,
		}
	}
	for _, region := range m.Regions {
		copyRegion := &MultiregionRegion{
			Name:        region.Name,
			Count:       region.Count,
			Datacenters: []string{},
			Meta:        map[string]string{},
		}
		copyRegion.Datacenters = append(copyRegion.Datacenters, region.Datacenters...)
		for k, v := range region.Meta {
			copyRegion.Meta[k] = v
		}
		copy.Regions = append(copy.Regions, copyRegion)
	}
	return copy
}

type MultiregionStrategy struct {
	MaxParallel int
	OnFailure   string
}

type MultiregionRegion struct {
	Name        string
	Count       int
	Datacenters []string
	Meta        map[string]string
}

// Namespace allows logically grouping jobs and their associated objects.
type Namespace struct {
	// Name is the name of the namespace
	Name string

	// Description is a human readable description of the namespace
	Description string

	// Quota is the quota specification that the namespace should account
	// against.
	Quota string

	// Hash is the hash of the namespace which is used to efficiently replicate
	// cross-regions.
	Hash []byte

	// Raft Indexes
	CreateIndex uint64
	ModifyIndex uint64
}

func (n *Namespace) Validate() error {
	var mErr multierror.Error

	// Validate the name and description
	if !validNamespaceName.MatchString(n.Name) {
		err := fmt.Errorf("invalid name %q. Must match regex %s", n.Name, validNamespaceName)
		mErr.Errors = append(mErr.Errors, err)
	}
	if len(n.Description) > maxNamespaceDescriptionLength {
		err := fmt.Errorf("description longer than %d", maxNamespaceDescriptionLength)
		mErr.Errors = append(mErr.Errors, err)
	}

	return mErr.ErrorOrNil()
}

// SetHash is used to compute and set the hash of the namespace
func (n *Namespace) SetHash() []byte {
	// Initialize a 256bit Blake2 hash (32 bytes)
	hash, err := blake2b.New256(nil)
	if err != nil {
		panic(err)
	}

	// Write all the user set fields
	_, _ = hash.Write([]byte(n.Name))
	_, _ = hash.Write([]byte(n.Description))
	_, _ = hash.Write([]byte(n.Quota))

	// Finalize the hash
	hashVal := hash.Sum(nil)

	// Set and return the hash
	n.Hash = hashVal
	return hashVal
}

func (n *Namespace) Copy() *Namespace {
	nc := new(Namespace)
	*nc = *n
	nc.Hash = make([]byte, len(n.Hash))
	copy(nc.Hash, n.Hash)
	return nc
}

// NamespaceListRequest is used to request a list of namespaces
type NamespaceListRequest struct {
	QueryOptions
}

// NamespaceListResponse is used for a list request
type NamespaceListResponse struct {
	Namespaces []*Namespace
	QueryMeta
}

// NamespaceSpecificRequest is used to query a specific namespace
type NamespaceSpecificRequest struct {
	Name string
	QueryOptions
}

// SingleNamespaceResponse is used to return a single namespace
type SingleNamespaceResponse struct {
	Namespace *Namespace
	QueryMeta
}

// NamespaceSetRequest is used to query a set of namespaces
type NamespaceSetRequest struct {
	Namespaces []string
	QueryOptions
}

// NamespaceSetResponse is used to return a set of namespaces
type NamespaceSetResponse struct {
	Namespaces map[string]*Namespace // Keyed by namespace Name
	QueryMeta
}

// NamespaceDeleteRequest is used to delete a set of namespaces
type NamespaceDeleteRequest struct {
	Namespaces []string
	WriteRequest
}

// NamespaceUpsertRequest is used to upsert a set of namespaces
type NamespaceUpsertRequest struct {
	Namespaces []*Namespace
	WriteRequest
}

const (
	// PeriodicSpecCron is used for a cron spec.
	PeriodicSpecCron = "cron"

	// PeriodicSpecTest is only used by unit tests. It is a sorted, comma
	// separated list of unix timestamps at which to launch.
	PeriodicSpecTest = "_internal_test"
)

// Periodic defines the interval a job should be run at.
type PeriodicConfig struct {
	// Enabled determines if the job should be run periodically.
	Enabled bool

	// Spec specifies the interval the job should be run as. It is parsed based
	// on the SpecType.
	Spec string

	// SpecType defines the format of the spec.
	SpecType string

	// ProhibitOverlap enforces that spawned jobs do not run in parallel.
	ProhibitOverlap bool

	// TimeZone is the user specified string that determines the time zone to
	// launch against. The time zones must be specified from IANA Time Zone
	// database, such as "America/New_York".
	// Reference: https://en.wikipedia.org/wiki/List_of_tz_database_time_zones
	// Reference: https://www.iana.org/time-zones
	TimeZone string

	// location is the time zone to evaluate the launch time against
	location *time.Location
}

func (p *PeriodicConfig) Copy() *PeriodicConfig {
	if p == nil {
		return nil
	}
	np := new(PeriodicConfig)
	*np = *p
	return np
}

func (p *PeriodicConfig) Validate() error {
	if !p.Enabled {
		return nil
	}

	var mErr multierror.Error
	if p.Spec == "" {
		_ = multierror.Append(&mErr, fmt.Errorf("Must specify a spec"))
	}

	// Check if we got a valid time zone
	if p.TimeZone != "" {
		if _, err := time.LoadLocation(p.TimeZone); err != nil {
			_ = multierror.Append(&mErr, fmt.Errorf("Invalid time zone %q: %v", p.TimeZone, err))
		}
	}

	switch p.SpecType {
	case PeriodicSpecCron:
		// Validate the cron spec
		if _, err := cronexpr.Parse(p.Spec); err != nil {
			_ = multierror.Append(&mErr, fmt.Errorf("Invalid cron spec %q: %v", p.Spec, err))
		}
	case PeriodicSpecTest:
		// No-op
	default:
		_ = multierror.Append(&mErr, fmt.Errorf("Unknown periodic specification type %q", p.SpecType))
	}

	return mErr.ErrorOrNil()
}

func (p *PeriodicConfig) Canonicalize() {
	// Load the location
	l, err := time.LoadLocation(p.TimeZone)
	if err != nil {
		p.location = time.UTC
	}

	p.location = l
}

// CronParseNext is a helper that parses the next time for the given expression
// but captures any panic that may occur in the underlying library.
func CronParseNext(e *cronexpr.Expression, fromTime time.Time, spec string) (t time.Time, err error) {
	defer func() {
		if recover() != nil {
			t = time.Time{}
			err = fmt.Errorf("failed parsing cron expression: %q", spec)
		}
	}()

	return e.Next(fromTime), nil
}

// Next returns the closest time instant matching the spec that is after the
// passed time. If no matching instance exists, the zero value of time.Time is
// returned. The `time.Location` of the returned value matches that of the
// passed time.
func (p *PeriodicConfig) Next(fromTime time.Time) (time.Time, error) {
	switch p.SpecType {
	case PeriodicSpecCron:
		e, err := cronexpr.Parse(p.Spec)
		if err != nil {
			return time.Time{}, fmt.Errorf("failed parsing cron expression: %q: %v", p.Spec, err)
		}
		return CronParseNext(e, fromTime, p.Spec)
	case PeriodicSpecTest:
		split := strings.Split(p.Spec, ",")
		if len(split) == 1 && split[0] == "" {
			return time.Time{}, nil
		}

		// Parse the times
		times := make([]time.Time, len(split))
		for i, s := range split {
			unix, err := strconv.Atoi(s)
			if err != nil {
				return time.Time{}, nil
			}

			times[i] = time.Unix(int64(unix), 0)
		}

		// Find the next match
		for _, next := range times {
			if fromTime.Before(next) {
				return next, nil
			}
		}
	}

	return time.Time{}, nil
}

// GetLocation returns the location to use for determining the time zone to run
// the periodic job against.
func (p *PeriodicConfig) GetLocation() *time.Location {
	// Jobs pre 0.5.5 will not have this
	if p.location != nil {
		return p.location
	}

	return time.UTC
}

const (
	// PeriodicLaunchSuffix is the string appended to the periodic jobs ID
	// when launching derived instances of it.
	PeriodicLaunchSuffix = "/periodic-"
)

// PeriodicLaunch tracks the last launch time of a periodic job.
type PeriodicLaunch struct {
	ID        string    // ID of the periodic job.
	Namespace string    // Namespace of the periodic job
	Launch    time.Time // The last launch time.

	// Raft Indexes
	CreateIndex uint64
	ModifyIndex uint64
}

const (
	DispatchPayloadForbidden = "forbidden"
	DispatchPayloadOptional  = "optional"
	DispatchPayloadRequired  = "required"

	// DispatchLaunchSuffix is the string appended to the parameterized job's ID
	// when dispatching instances of it.
	DispatchLaunchSuffix = "/dispatch-"
)

// ParameterizedJobConfig is used to configure the parameterized job
type ParameterizedJobConfig struct {
	// Payload configure the payload requirements
	Payload string

	// MetaRequired is metadata keys that must be specified by the dispatcher
	MetaRequired []string

	// MetaOptional is metadata keys that may be specified by the dispatcher
	MetaOptional []string
}

func (d *ParameterizedJobConfig) Validate() error {
	var mErr multierror.Error
	switch d.Payload {
	case DispatchPayloadOptional, DispatchPayloadRequired, DispatchPayloadForbidden:
	default:
		_ = multierror.Append(&mErr, fmt.Errorf("Unknown payload requirement: %q", d.Payload))
	}

	// Check that the meta configurations are disjoint sets
	disjoint, offending := helper.SliceSetDisjoint(d.MetaRequired, d.MetaOptional)
	if !disjoint {
		_ = multierror.Append(&mErr, fmt.Errorf("Required and optional meta keys should be disjoint. Following keys exist in both: %v", offending))
	}

	return mErr.ErrorOrNil()
}

func (d *ParameterizedJobConfig) Canonicalize() {
	if d.Payload == "" {
		d.Payload = DispatchPayloadOptional
	}
}

func (d *ParameterizedJobConfig) Copy() *ParameterizedJobConfig {
	if d == nil {
		return nil
	}
	nd := new(ParameterizedJobConfig)
	*nd = *d
	nd.MetaOptional = helper.CopySliceString(nd.MetaOptional)
	nd.MetaRequired = helper.CopySliceString(nd.MetaRequired)
	return nd
}

// DispatchedID returns an ID appropriate for a job dispatched against a
// particular parameterized job
func DispatchedID(templateID string, t time.Time) string {
	u := uuid.Generate()[:8]
	return fmt.Sprintf("%s%s%d-%s", templateID, DispatchLaunchSuffix, t.Unix(), u)
}

// DispatchPayloadConfig configures how a task gets its input from a job dispatch
type DispatchPayloadConfig struct {
	// File specifies a relative path to where the input data should be written
	File string
}

func (d *DispatchPayloadConfig) Copy() *DispatchPayloadConfig {
	if d == nil {
		return nil
	}
	nd := new(DispatchPayloadConfig)
	*nd = *d
	return nd
}

func (d *DispatchPayloadConfig) Validate() error {
	// Verify the destination doesn't escape
	escaped, err := PathEscapesAllocDir("task/local/", d.File)
	if err != nil {
		return fmt.Errorf("invalid destination path: %v", err)
	} else if escaped {
		return fmt.Errorf("destination escapes allocation directory")
	}

	return nil
}

const (
	TaskLifecycleHookPrestart  = "prestart"
	TaskLifecycleHookPoststart = "poststart"
	TaskLifecycleHookPoststop  = "poststop"
)

type TaskLifecycleConfig struct {
	Hook    string
	Sidecar bool
}

func (d *TaskLifecycleConfig) Copy() *TaskLifecycleConfig {
	if d == nil {
		return nil
	}
	nd := new(TaskLifecycleConfig)
	*nd = *d
	return nd
}

func (d *TaskLifecycleConfig) Validate() error {
	if d == nil {
		return nil
	}

	switch d.Hook {
	case TaskLifecycleHookPrestart:
	case TaskLifecycleHookPoststart:
	case TaskLifecycleHookPoststop:
	case "":
		return fmt.Errorf("no lifecycle hook provided")
	default:
		return fmt.Errorf("invalid hook: %v", d.Hook)
	}

	return nil
}

var (
	// These default restart policies needs to be in sync with
	// Canonicalize in api/tasks.go

	DefaultServiceJobRestartPolicy = RestartPolicy{
		Delay:    15 * time.Second,
		Attempts: 2,
		Interval: 30 * time.Minute,
		Mode:     RestartPolicyModeFail,
	}
	DefaultBatchJobRestartPolicy = RestartPolicy{
		Delay:    15 * time.Second,
		Attempts: 3,
		Interval: 24 * time.Hour,
		Mode:     RestartPolicyModeFail,
	}
)

var (
	// These default reschedule policies needs to be in sync with
	// NewDefaultReschedulePolicy in api/tasks.go

	DefaultServiceJobReschedulePolicy = ReschedulePolicy{
		Delay:         30 * time.Second,
		DelayFunction: "exponential",
		MaxDelay:      1 * time.Hour,
		Unlimited:     true,
	}
	DefaultBatchJobReschedulePolicy = ReschedulePolicy{
		Attempts:      1,
		Interval:      24 * time.Hour,
		Delay:         5 * time.Second,
		DelayFunction: "constant",
	}
)

const (
	// RestartPolicyModeDelay causes an artificial delay till the next interval is
	// reached when the specified attempts have been reached in the interval.
	RestartPolicyModeDelay = "delay"

	// RestartPolicyModeFail causes a job to fail if the specified number of
	// attempts are reached within an interval.
	RestartPolicyModeFail = "fail"

	// RestartPolicyMinInterval is the minimum interval that is accepted for a
	// restart policy.
	RestartPolicyMinInterval = 5 * time.Second

	// ReasonWithinPolicy describes restart events that are within policy
	ReasonWithinPolicy = "Restart within policy"
)

// JobScalingEvents contains the scaling events for a given job
type JobScalingEvents struct {
	Namespace string
	JobID     string

	// This map is indexed by target; currently, this is just task group
	// the indexed array is sorted from newest to oldest event
	// the array should have less than JobTrackedScalingEvents entries
	ScalingEvents map[string][]*ScalingEvent

	// Raft index
	ModifyIndex uint64
}

// Factory method for ScalingEvent objects
func NewScalingEvent(message string) *ScalingEvent {
	return &ScalingEvent{
		Time:    time.Now().Unix(),
		Message: message,
	}
}

// ScalingEvent describes a scaling event against a Job
type ScalingEvent struct {
	// Unix Nanosecond timestamp for the scaling event
	Time int64

	// Count is the new scaling count, if provided
	Count *int64

	// PreviousCount is the count at the time of the scaling event
	PreviousCount int64

	// Message is the message describing a scaling event
	Message string

	// Error indicates an error state for this scaling event
	Error bool

	// Meta is a map of metadata returned during a scaling event
	Meta map[string]interface{}

	// EvalID is the ID for an evaluation if one was created as part of a scaling event
	EvalID *string

	// Raft index
	CreateIndex uint64
}

func (e *ScalingEvent) SetError(error bool) *ScalingEvent {
	e.Error = error
	return e
}

func (e *ScalingEvent) SetMeta(meta map[string]interface{}) *ScalingEvent {
	e.Meta = meta
	return e
}

func (e *ScalingEvent) SetEvalID(evalID string) *ScalingEvent {
	e.EvalID = &evalID
	return e
}

// ScalingEventRequest is by for Job.Scale endpoint
// to register scaling events
type ScalingEventRequest struct {
	Namespace string
	JobID     string
	TaskGroup string

	ScalingEvent *ScalingEvent
}

// ScalingPolicy specifies the scaling policy for a scaling target
type ScalingPolicy struct {
	// ID is a generated UUID used for looking up the scaling policy
	ID string

	// Type is the type of scaling performed by the policy
	Type string

	// Target contains information about the target of the scaling policy, like job and group
	Target map[string]string

	// Policy is an opaque description of the scaling policy, passed to the autoscaler
	Policy map[string]interface{}

	// Min is the minimum allowable scaling count for this target
	Min int64

	// Max is the maximum allowable scaling count for this target
	Max int64

	// Enabled indicates whether this policy has been enabled/disabled
	Enabled bool

	CreateIndex uint64
	ModifyIndex uint64
}

// JobKey returns a key that is unique to a job-scoped target, useful as a map
// key. This uses the policy type, plus target (group and task).
func (p *ScalingPolicy) JobKey() string {
	return p.Type + "\000" +
		p.Target[ScalingTargetGroup] + "\000" +
		p.Target[ScalingTargetTask]
}

const (
	ScalingTargetNamespace = "Namespace"
	ScalingTargetJob       = "Job"
	ScalingTargetGroup     = "Group"
	ScalingTargetTask      = "Task"

	ScalingPolicyTypeHorizontal = "horizontal"
)

func (p *ScalingPolicy) Canonicalize() {
	if p.Type == "" {
		p.Type = ScalingPolicyTypeHorizontal
	}
}

func (p *ScalingPolicy) Copy() *ScalingPolicy {
	if p == nil {
		return nil
	}

	opaquePolicyConfig, err := copystructure.Copy(p.Policy)
	if err != nil {
		panic(err.Error())
	}

	c := ScalingPolicy{
		ID:          p.ID,
		Policy:      opaquePolicyConfig.(map[string]interface{}),
		Enabled:     p.Enabled,
		Type:        p.Type,
		Min:         p.Min,
		Max:         p.Max,
		CreateIndex: p.CreateIndex,
		ModifyIndex: p.ModifyIndex,
	}
	c.Target = make(map[string]string, len(p.Target))
	for k, v := range p.Target {
		c.Target[k] = v
	}
	return &c
}

func (p *ScalingPolicy) Validate() error {
	if p == nil {
		return nil
	}

	var mErr multierror.Error

	// Check policy type and target
	if p.Type == "" {
		mErr.Errors = append(mErr.Errors, fmt.Errorf("missing scaling policy type"))
	} else {
		mErr.Errors = append(mErr.Errors, p.validateType().Errors...)
	}

	// Check Min and Max
	if p.Max < 0 {
		mErr.Errors = append(mErr.Errors,
			fmt.Errorf("maximum count must be specified and non-negative"))
	} else if p.Max < p.Min {
		mErr.Errors = append(mErr.Errors,
			fmt.Errorf("maximum count must not be less than minimum count"))
	}

	if p.Min < 0 {
		mErr.Errors = append(mErr.Errors,
			fmt.Errorf("minimum count must be specified and non-negative"))
	}

	return mErr.ErrorOrNil()
}

func (p *ScalingPolicy) validateTargetHorizontal() (mErr multierror.Error) {
	if len(p.Target) == 0 {
		// This is probably not a Nomad horizontal policy
		return
	}

	// Nomad horizontal policies should have Namespace, Job and TaskGroup
	if p.Target[ScalingTargetNamespace] == "" {
		mErr.Errors = append(mErr.Errors, fmt.Errorf("missing target namespace"))
	}
	if p.Target[ScalingTargetJob] == "" {
		mErr.Errors = append(mErr.Errors, fmt.Errorf("missing target job"))
	}
	if p.Target[ScalingTargetGroup] == "" {
		mErr.Errors = append(mErr.Errors, fmt.Errorf("missing target group"))
	}
	return
}

// Diff indicates whether the specification for a given scaling policy has changed
func (p *ScalingPolicy) Diff(p2 *ScalingPolicy) bool {
	copy := *p2
	copy.ID = p.ID
	copy.CreateIndex = p.CreateIndex
	copy.ModifyIndex = p.ModifyIndex
	return !reflect.DeepEqual(*p, copy)
}

// TarketTaskGroup updates a ScalingPolicy target to specify a given task group
func (p *ScalingPolicy) TargetTaskGroup(job *Job, tg *TaskGroup) *ScalingPolicy {
	p.Target = map[string]string{
		ScalingTargetNamespace: job.Namespace,
		ScalingTargetJob:       job.ID,
		ScalingTargetGroup:     tg.Name,
	}
	return p
}

// TargetTask updates a ScalingPolicy target to specify a given task
func (p *ScalingPolicy) TargetTask(job *Job, tg *TaskGroup, task *Task) *ScalingPolicy {
	p.TargetTaskGroup(job, tg)
	p.Target[ScalingTargetTask] = task.Name
	return p
}

func (p *ScalingPolicy) Stub() *ScalingPolicyListStub {
	stub := &ScalingPolicyListStub{
		ID:          p.ID,
		Type:        p.Type,
		Target:      make(map[string]string),
		Enabled:     p.Enabled,
		CreateIndex: p.CreateIndex,
		ModifyIndex: p.ModifyIndex,
	}
	for k, v := range p.Target {
		stub.Target[k] = v
	}
	return stub
}

// GetScalingPolicies returns a slice of all scaling scaling policies for this job
func (j *Job) GetScalingPolicies() []*ScalingPolicy {
	ret := make([]*ScalingPolicy, 0)

	for _, tg := range j.TaskGroups {
		if tg.Scaling != nil {
			ret = append(ret, tg.Scaling)
		}
	}

	ret = append(ret, j.GetEntScalingPolicies()...)

	return ret
}

// ScalingPolicyListStub is used to return a subset of scaling policy information
// for the scaling policy list
type ScalingPolicyListStub struct {
	ID          string
	Enabled     bool
	Type        string
	Target      map[string]string
	CreateIndex uint64
	ModifyIndex uint64
}

// RestartPolicy configures how Tasks are restarted when they crash or fail.
type RestartPolicy struct {
	// Attempts is the number of restart that will occur in an interval.
	Attempts int

	// Interval is a duration in which we can limit the number of restarts
	// within.
	Interval time.Duration

	// Delay is the time between a failure and a restart.
	Delay time.Duration

	// Mode controls what happens when the task restarts more than attempt times
	// in an interval.
	Mode string
}

func (r *RestartPolicy) Copy() *RestartPolicy {
	if r == nil {
		return nil
	}
	nrp := new(RestartPolicy)
	*nrp = *r
	return nrp
}

func (r *RestartPolicy) Validate() error {
	var mErr multierror.Error
	switch r.Mode {
	case RestartPolicyModeDelay, RestartPolicyModeFail:
	default:
		_ = multierror.Append(&mErr, fmt.Errorf("Unsupported restart mode: %q", r.Mode))
	}

	// Check for ambiguous/confusing settings
	if r.Attempts == 0 && r.Mode != RestartPolicyModeFail {
		_ = multierror.Append(&mErr, fmt.Errorf("Restart policy %q with %d attempts is ambiguous", r.Mode, r.Attempts))
	}

	if r.Interval.Nanoseconds() < RestartPolicyMinInterval.Nanoseconds() {
		_ = multierror.Append(&mErr, fmt.Errorf("Interval can not be less than %v (got %v)", RestartPolicyMinInterval, r.Interval))
	}
	if time.Duration(r.Attempts)*r.Delay > r.Interval {
		_ = multierror.Append(&mErr,
			fmt.Errorf("Nomad can't restart the TaskGroup %v times in an interval of %v with a delay of %v", r.Attempts, r.Interval, r.Delay))
	}
	return mErr.ErrorOrNil()
}

func NewRestartPolicy(jobType string) *RestartPolicy {
	switch jobType {
	case JobTypeService, JobTypeSystem:
		rp := DefaultServiceJobRestartPolicy
		return &rp
	case JobTypeBatch:
		rp := DefaultBatchJobRestartPolicy
		return &rp
	}
	return nil
}

const ReschedulePolicyMinInterval = 15 * time.Second
const ReschedulePolicyMinDelay = 5 * time.Second

var RescheduleDelayFunctions = [...]string{"constant", "exponential", "fibonacci"}

// ReschedulePolicy configures how Tasks are rescheduled  when they crash or fail.
type ReschedulePolicy struct {
	// Attempts limits the number of rescheduling attempts that can occur in an interval.
	Attempts int

	// Interval is a duration in which we can limit the number of reschedule attempts.
	Interval time.Duration

	// Delay is a minimum duration to wait between reschedule attempts.
	// The delay function determines how much subsequent reschedule attempts are delayed by.
	Delay time.Duration

	// DelayFunction determines how the delay progressively changes on subsequent reschedule
	// attempts. Valid values are "exponential", "constant", and "fibonacci".
	DelayFunction string

	// MaxDelay is an upper bound on the delay.
	MaxDelay time.Duration

	// Unlimited allows infinite rescheduling attempts. Only allowed when delay is set
	// between reschedule attempts.
	Unlimited bool
}

func (r *ReschedulePolicy) Copy() *ReschedulePolicy {
	if r == nil {
		return nil
	}
	nrp := new(ReschedulePolicy)
	*nrp = *r
	return nrp
}

func (r *ReschedulePolicy) Enabled() bool {
	enabled := r != nil && (r.Attempts > 0 || r.Unlimited)
	return enabled
}

// Validate uses different criteria to validate the reschedule policy
// Delay must be a minimum of 5 seconds
// Delay Ceiling is ignored if Delay Function is "constant"
// Number of possible attempts is validated, given the interval, delay and delay function
func (r *ReschedulePolicy) Validate() error {
	if !r.Enabled() {
		return nil
	}
	var mErr multierror.Error
	// Check for ambiguous/confusing settings
	if r.Attempts > 0 {
		if r.Interval <= 0 {
			_ = multierror.Append(&mErr, fmt.Errorf("Interval must be a non zero value if Attempts > 0"))
		}
		if r.Unlimited {
			_ = multierror.Append(&mErr, fmt.Errorf("Reschedule Policy with Attempts = %v, Interval = %v, "+
				"and Unlimited = %v is ambiguous", r.Attempts, r.Interval, r.Unlimited))
			_ = multierror.Append(&mErr, errors.New("If Attempts >0, Unlimited cannot also be set to true"))
		}
	}

	delayPreCheck := true
	// Delay should be bigger than the default
	if r.Delay.Nanoseconds() < ReschedulePolicyMinDelay.Nanoseconds() {
		_ = multierror.Append(&mErr, fmt.Errorf("Delay cannot be less than %v (got %v)", ReschedulePolicyMinDelay, r.Delay))
		delayPreCheck = false
	}

	// Must use a valid delay function
	if !isValidDelayFunction(r.DelayFunction) {
		_ = multierror.Append(&mErr, fmt.Errorf("Invalid delay function %q, must be one of %q", r.DelayFunction, RescheduleDelayFunctions))
		delayPreCheck = false
	}

	// Validate MaxDelay if not using linear delay progression
	if r.DelayFunction != "constant" {
		if r.MaxDelay.Nanoseconds() < ReschedulePolicyMinDelay.Nanoseconds() {
			_ = multierror.Append(&mErr, fmt.Errorf("Max Delay cannot be less than %v (got %v)", ReschedulePolicyMinDelay, r.Delay))
			delayPreCheck = false
		}
		if r.MaxDelay < r.Delay {
			_ = multierror.Append(&mErr, fmt.Errorf("Max Delay cannot be less than Delay %v (got %v)", r.Delay, r.MaxDelay))
			delayPreCheck = false
		}

	}

	// Validate Interval and other delay parameters if attempts are limited
	if !r.Unlimited {
		if r.Interval.Nanoseconds() < ReschedulePolicyMinInterval.Nanoseconds() {
			_ = multierror.Append(&mErr, fmt.Errorf("Interval cannot be less than %v (got %v)", ReschedulePolicyMinInterval, r.Interval))
		}
		if !delayPreCheck {
			// We can't cross validate the rest of the delay params if delayPreCheck fails, so return early
			return mErr.ErrorOrNil()
		}
		crossValidationErr := r.validateDelayParams()
		if crossValidationErr != nil {
			_ = multierror.Append(&mErr, crossValidationErr)
		}
	}
	return mErr.ErrorOrNil()
}

func isValidDelayFunction(delayFunc string) bool {
	for _, value := range RescheduleDelayFunctions {
		if value == delayFunc {
			return true
		}
	}
	return false
}

func (r *ReschedulePolicy) validateDelayParams() error {
	ok, possibleAttempts, recommendedInterval := r.viableAttempts()
	if ok {
		return nil
	}
	var mErr multierror.Error
	if r.DelayFunction == "constant" {
		_ = multierror.Append(&mErr, fmt.Errorf("Nomad can only make %v attempts in %v with initial delay %v and "+
			"delay function %q", possibleAttempts, r.Interval, r.Delay, r.DelayFunction))
	} else {
		_ = multierror.Append(&mErr, fmt.Errorf("Nomad can only make %v attempts in %v with initial delay %v, "+
			"delay function %q, and delay ceiling %v", possibleAttempts, r.Interval, r.Delay, r.DelayFunction, r.MaxDelay))
	}
	_ = multierror.Append(&mErr, fmt.Errorf("Set the interval to at least %v to accommodate %v attempts", recommendedInterval.Round(time.Second), r.Attempts))
	return mErr.ErrorOrNil()
}

func (r *ReschedulePolicy) viableAttempts() (bool, int, time.Duration) {
	var possibleAttempts int
	var recommendedInterval time.Duration
	valid := true
	switch r.DelayFunction {
	case "constant":
		recommendedInterval = time.Duration(r.Attempts) * r.Delay
		if r.Interval < recommendedInterval {
			possibleAttempts = int(r.Interval / r.Delay)
			valid = false
		}
	case "exponential":
		for i := 0; i < r.Attempts; i++ {
			nextDelay := time.Duration(math.Pow(2, float64(i))) * r.Delay
			if nextDelay > r.MaxDelay {
				nextDelay = r.MaxDelay
				recommendedInterval += nextDelay
			} else {
				recommendedInterval = nextDelay
			}
			if recommendedInterval < r.Interval {
				possibleAttempts++
			}
		}
		if possibleAttempts < r.Attempts {
			valid = false
		}
	case "fibonacci":
		var slots []time.Duration
		slots = append(slots, r.Delay)
		slots = append(slots, r.Delay)
		reachedCeiling := false
		for i := 2; i < r.Attempts; i++ {
			var nextDelay time.Duration
			if reachedCeiling {
				//switch to linear
				nextDelay = slots[i-1] + r.MaxDelay
			} else {
				nextDelay = slots[i-1] + slots[i-2]
				if nextDelay > r.MaxDelay {
					nextDelay = r.MaxDelay
					reachedCeiling = true
				}
			}
			slots = append(slots, nextDelay)
		}
		recommendedInterval = slots[len(slots)-1]
		if r.Interval < recommendedInterval {
			valid = false
			// calculate possible attempts
			for i := 0; i < len(slots); i++ {
				if slots[i] > r.Interval {
					possibleAttempts = i
					break
				}
			}
		}
	default:
		return false, 0, 0
	}
	if possibleAttempts < 0 { // can happen if delay is bigger than interval
		possibleAttempts = 0
	}
	return valid, possibleAttempts, recommendedInterval
}

func NewReschedulePolicy(jobType string) *ReschedulePolicy {
	switch jobType {
	case JobTypeService:
		rp := DefaultServiceJobReschedulePolicy
		return &rp
	case JobTypeBatch:
		rp := DefaultBatchJobReschedulePolicy
		return &rp
	}
	return nil
}

const (
	MigrateStrategyHealthChecks = "checks"
	MigrateStrategyHealthStates = "task_states"
)

type MigrateStrategy struct {
	MaxParallel     int
	HealthCheck     string
	MinHealthyTime  time.Duration
	HealthyDeadline time.Duration
}

// DefaultMigrateStrategy is used for backwards compat with pre-0.8 Allocations
// that lack an update strategy.
//
// This function should match its counterpart in api/tasks.go
func DefaultMigrateStrategy() *MigrateStrategy {
	return &MigrateStrategy{
		MaxParallel:     1,
		HealthCheck:     MigrateStrategyHealthChecks,
		MinHealthyTime:  10 * time.Second,
		HealthyDeadline: 5 * time.Minute,
	}
}

func (m *MigrateStrategy) Validate() error {
	var mErr multierror.Error

	if m.MaxParallel < 0 {
		_ = multierror.Append(&mErr, fmt.Errorf("MaxParallel must be >= 0 but found %d", m.MaxParallel))
	}

	switch m.HealthCheck {
	case MigrateStrategyHealthChecks, MigrateStrategyHealthStates:
		// ok
	case "":
		if m.MaxParallel > 0 {
			_ = multierror.Append(&mErr, fmt.Errorf("Missing HealthCheck"))
		}
	default:
		_ = multierror.Append(&mErr, fmt.Errorf("Invalid HealthCheck: %q", m.HealthCheck))
	}

	if m.MinHealthyTime < 0 {
		_ = multierror.Append(&mErr, fmt.Errorf("MinHealthyTime is %s and must be >= 0", m.MinHealthyTime))
	}

	if m.HealthyDeadline < 0 {
		_ = multierror.Append(&mErr, fmt.Errorf("HealthyDeadline is %s and must be >= 0", m.HealthyDeadline))
	}

	if m.MinHealthyTime > m.HealthyDeadline {
		_ = multierror.Append(&mErr, fmt.Errorf("MinHealthyTime must be less than HealthyDeadline"))
	}

	return mErr.ErrorOrNil()
}

// TaskGroup is an atomic unit of placement. Each task group belongs to
// a job and may contain any number of tasks. A task group support running
// in many replicas using the same configuration..
type TaskGroup struct {
	// Name of the task group
	Name string

	// Count is the number of replicas of this task group that should
	// be scheduled.
	Count int

	// Update is used to control the update strategy for this task group
	Update *UpdateStrategy

	// Migrate is used to control the migration strategy for this task group
	Migrate *MigrateStrategy

	// Constraints can be specified at a task group level and apply to
	// all the tasks contained.
	Constraints []*Constraint

	// Scaling is the list of autoscaling policies for the TaskGroup
	Scaling *ScalingPolicy

	// RestartPolicy of a TaskGroup
	RestartPolicy *RestartPolicy

	// Tasks are the collection of tasks that this task group needs to run
	Tasks []*Task

	// EphemeralDisk is the disk resources that the task group requests
	EphemeralDisk *EphemeralDisk

	// Meta is used to associate arbitrary metadata with this
	// task group. This is opaque to Nomad.
	Meta map[string]string

	// ReschedulePolicy is used to configure how the scheduler should
	// retry failed allocations.
	ReschedulePolicy *ReschedulePolicy

	// Affinities can be specified at the task group level to express
	// scheduling preferences.
	Affinities []*Affinity

	// Spread can be specified at the task group level to express spreading
	// allocations across a desired attribute, such as datacenter
	Spreads []*Spread

	// Networks are the network configuration for the task group. This can be
	// overridden in the task.
	Networks Networks

	// Services this group provides
	Services []*Service

	// Volumes is a map of volumes that have been requested by the task group.
	Volumes map[string]*VolumeRequest

	// ShutdownDelay is the amount of time to wait between deregistering
	// group services in consul and stopping tasks.
	ShutdownDelay *time.Duration

	// StopAfterClientDisconnect, if set, configures the client to stop the task group
	// after this duration since the last known good heartbeat
	StopAfterClientDisconnect *time.Duration
}

func (tg *TaskGroup) Copy() *TaskGroup {
	if tg == nil {
		return nil
	}
	ntg := new(TaskGroup)
	*ntg = *tg
	ntg.Update = ntg.Update.Copy()
	ntg.Constraints = CopySliceConstraints(ntg.Constraints)
	ntg.RestartPolicy = ntg.RestartPolicy.Copy()
	ntg.ReschedulePolicy = ntg.ReschedulePolicy.Copy()
	ntg.Affinities = CopySliceAffinities(ntg.Affinities)
	ntg.Spreads = CopySliceSpreads(ntg.Spreads)
	ntg.Volumes = CopyMapVolumeRequest(ntg.Volumes)
	ntg.Scaling = ntg.Scaling.Copy()

	// Copy the network objects
	if tg.Networks != nil {
		n := len(tg.Networks)
		ntg.Networks = make([]*NetworkResource, n)
		for i := 0; i < n; i++ {
			ntg.Networks[i] = tg.Networks[i].Copy()
		}
	}

	if tg.Tasks != nil {
		tasks := make([]*Task, len(ntg.Tasks))
		for i, t := range ntg.Tasks {
			tasks[i] = t.Copy()
		}
		ntg.Tasks = tasks
	}

	ntg.Meta = helper.CopyMapStringString(ntg.Meta)

	if tg.EphemeralDisk != nil {
		ntg.EphemeralDisk = tg.EphemeralDisk.Copy()
	}

	if tg.Services != nil {
		ntg.Services = make([]*Service, len(tg.Services))
		for i, s := range tg.Services {
			ntg.Services[i] = s.Copy()
		}
	}

	if tg.ShutdownDelay != nil {
		ntg.ShutdownDelay = tg.ShutdownDelay
	}

	if tg.StopAfterClientDisconnect != nil {
		ntg.StopAfterClientDisconnect = tg.StopAfterClientDisconnect
	}

	return ntg
}

// Canonicalize is used to canonicalize fields in the TaskGroup.
func (tg *TaskGroup) Canonicalize(job *Job) {
	// Ensure that an empty and nil map are treated the same to avoid scheduling
	// problems since we use reflect DeepEquals.
	if len(tg.Meta) == 0 {
		tg.Meta = nil
	}

	// Set the default restart policy.
	if tg.RestartPolicy == nil {
		tg.RestartPolicy = NewRestartPolicy(job.Type)
	}

	if tg.ReschedulePolicy == nil {
		tg.ReschedulePolicy = NewReschedulePolicy(job.Type)
	}

	// Canonicalize Migrate for service jobs
	if job.Type == JobTypeService && tg.Migrate == nil {
		tg.Migrate = DefaultMigrateStrategy()
	}

	// Set a default ephemeral disk object if the user has not requested for one
	if tg.EphemeralDisk == nil {
		tg.EphemeralDisk = DefaultEphemeralDisk()
	}

	if tg.Scaling != nil {
		tg.Scaling.Canonicalize()
	}

	for _, service := range tg.Services {
		service.Canonicalize(job.Name, tg.Name, "group")
	}

	for _, network := range tg.Networks {
		network.Canonicalize()
	}

	for _, task := range tg.Tasks {
		task.Canonicalize(job, tg)
	}
}

// Validate is used to sanity check a task group
func (tg *TaskGroup) Validate(j *Job) error {
	var mErr multierror.Error
	if tg.Name == "" {
		mErr.Errors = append(mErr.Errors, errors.New("Missing task group name"))
	} else if strings.Contains(tg.Name, "\000") {
		mErr.Errors = append(mErr.Errors, errors.New("Task group name contains null character"))
	}
	if tg.Count < 0 {
		mErr.Errors = append(mErr.Errors, errors.New("Task group count can't be negative"))
	}
	if len(tg.Tasks) == 0 {
		// could be a lone consul gateway inserted by the connect mutator
		mErr.Errors = append(mErr.Errors, errors.New("Missing tasks for task group"))
	}

	for idx, constr := range tg.Constraints {
		if err := constr.Validate(); err != nil {
			outer := fmt.Errorf("Constraint %d validation failed: %s", idx+1, err)
			mErr.Errors = append(mErr.Errors, outer)
		}
	}
	if j.Type == JobTypeSystem {
		if tg.Affinities != nil {
			mErr.Errors = append(mErr.Errors, fmt.Errorf("System jobs may not have an affinity stanza"))
		}
	} else {
		for idx, affinity := range tg.Affinities {
			if err := affinity.Validate(); err != nil {
				outer := fmt.Errorf("Affinity %d validation failed: %s", idx+1, err)
				mErr.Errors = append(mErr.Errors, outer)
			}
		}
	}

	if tg.RestartPolicy != nil {
		if err := tg.RestartPolicy.Validate(); err != nil {
			mErr.Errors = append(mErr.Errors, err)
		}
	} else {
		mErr.Errors = append(mErr.Errors, fmt.Errorf("Task Group %v should have a restart policy", tg.Name))
	}

	if j.Type == JobTypeSystem {
		if tg.Spreads != nil {
			mErr.Errors = append(mErr.Errors, fmt.Errorf("System jobs may not have a spread stanza"))
		}
	} else {
		for idx, spread := range tg.Spreads {
			if err := spread.Validate(); err != nil {
				outer := fmt.Errorf("Spread %d validation failed: %s", idx+1, err)
				mErr.Errors = append(mErr.Errors, outer)
			}
		}
	}

	if j.Type == JobTypeSystem {
		if tg.ReschedulePolicy != nil {
			mErr.Errors = append(mErr.Errors, fmt.Errorf("System jobs should not have a reschedule policy"))
		}
	} else {
		if tg.ReschedulePolicy != nil {
			if err := tg.ReschedulePolicy.Validate(); err != nil {
				mErr.Errors = append(mErr.Errors, err)
			}
		} else {
			mErr.Errors = append(mErr.Errors, fmt.Errorf("Task Group %v should have a reschedule policy", tg.Name))
		}
	}

	if tg.EphemeralDisk != nil {
		if err := tg.EphemeralDisk.Validate(); err != nil {
			mErr.Errors = append(mErr.Errors, err)
		}
	} else {
		mErr.Errors = append(mErr.Errors, fmt.Errorf("Task Group %v should have an ephemeral disk object", tg.Name))
	}

	// Validate the update strategy
	if u := tg.Update; u != nil {
		switch j.Type {
		case JobTypeService, JobTypeSystem:
		default:
			mErr.Errors = append(mErr.Errors, fmt.Errorf("Job type %q does not allow update block", j.Type))
		}
		if err := u.Validate(); err != nil {
			mErr.Errors = append(mErr.Errors, err)
		}
	}

	// Validate the migration strategy
	switch j.Type {
	case JobTypeService:
		if tg.Migrate != nil {
			if err := tg.Migrate.Validate(); err != nil {
				mErr.Errors = append(mErr.Errors, err)
			}
		}
	default:
		if tg.Migrate != nil {
			mErr.Errors = append(mErr.Errors, fmt.Errorf("Job type %q does not allow migrate block", j.Type))
		}
	}

	// Check that there is only one leader task if any
	tasks := make(map[string]int)
	leaderTasks := 0
	for idx, task := range tg.Tasks {
		if task.Name == "" {
			mErr.Errors = append(mErr.Errors, fmt.Errorf("Task %d missing name", idx+1))
		} else if existing, ok := tasks[task.Name]; ok {
			mErr.Errors = append(mErr.Errors, fmt.Errorf("Task %d redefines '%s' from task %d", idx+1, task.Name, existing+1))
		} else {
			tasks[task.Name] = idx
		}

		if task.Leader {
			leaderTasks++
		}
	}

	if leaderTasks > 1 {
		mErr.Errors = append(mErr.Errors, fmt.Errorf("Only one task may be marked as leader"))
	}

	// Validate the Host Volumes
	for name, decl := range tg.Volumes {
		if !(decl.Type == VolumeTypeHost ||
			decl.Type == VolumeTypeCSI) {
			mErr.Errors = append(mErr.Errors, fmt.Errorf("Volume %s has unrecognised type %s", name, decl.Type))
			continue
		}

		if decl.Source == "" {
			mErr.Errors = append(mErr.Errors, fmt.Errorf("Volume %s has an empty source", name))
		}
	}

	// Validate task group and task network resources
	if err := tg.validateNetworks(); err != nil {
		outer := fmt.Errorf("Task group network validation failed: %v", err)
		mErr.Errors = append(mErr.Errors, outer)
	}

	// Validate task group and task services
	if err := tg.validateServices(); err != nil {
		outer := fmt.Errorf("Task group service validation failed: %v", err)
		mErr.Errors = append(mErr.Errors, outer)
	}

	// Validate group service script-checks
	if err := tg.validateScriptChecksInGroupServices(); err != nil {
		outer := fmt.Errorf("Task group service check validation failed: %v", err)
		mErr.Errors = append(mErr.Errors, outer)
	}

	// Validate the scaling policy
	if err := tg.validateScalingPolicy(j); err != nil {
		outer := fmt.Errorf("Task group scaling policy validation failed: %v", err)
		mErr.Errors = append(mErr.Errors, outer)
	}

	// Validate the tasks
	for _, task := range tg.Tasks {
		// Validate the task does not reference undefined volume mounts
		for i, mnt := range task.VolumeMounts {
			if mnt.Volume == "" {
				mErr.Errors = append(mErr.Errors, fmt.Errorf("Task %s has a volume mount (%d) referencing an empty volume", task.Name, i))
				continue
			}

			if _, ok := tg.Volumes[mnt.Volume]; !ok {
				mErr.Errors = append(mErr.Errors, fmt.Errorf("Task %s has a volume mount (%d) referencing undefined volume %s", task.Name, i, mnt.Volume))
				continue
			}
		}

		if err := task.Validate(tg.EphemeralDisk, j.Type, tg.Services, tg.Networks); err != nil {
			outer := fmt.Errorf("Task %s validation failed: %v", task.Name, err)
			mErr.Errors = append(mErr.Errors, outer)
		}
	}
	return mErr.ErrorOrNil()
}

func (tg *TaskGroup) validateNetworks() error {
	var mErr multierror.Error
	portLabels := make(map[string]string)
	// host_network -> static port tracking
	staticPortsIndex := make(map[string]map[int]string)

	for _, net := range tg.Networks {
		for _, port := range append(net.ReservedPorts, net.DynamicPorts...) {
			if other, ok := portLabels[port.Label]; ok {
				mErr.Errors = append(mErr.Errors, fmt.Errorf("Port label %s already in use by %s", port.Label, other))
			} else {
				portLabels[port.Label] = "taskgroup network"
			}

			if port.Value != 0 {
				hostNetwork := port.HostNetwork
				if hostNetwork == "" {
					hostNetwork = "default"
				}
				staticPorts, ok := staticPortsIndex[hostNetwork]
				if !ok {
					staticPorts = make(map[int]string)
				}
				// static port
				if other, ok := staticPorts[port.Value]; ok {
					err := fmt.Errorf("Static port %d already reserved by %s", port.Value, other)
					mErr.Errors = append(mErr.Errors, err)
				} else if port.Value > math.MaxUint16 {
					err := fmt.Errorf("Port %s (%d) cannot be greater than %d", port.Label, port.Value, math.MaxUint16)
					mErr.Errors = append(mErr.Errors, err)
				} else {
					staticPorts[port.Value] = fmt.Sprintf("taskgroup network:%s", port.Label)
					staticPortsIndex[hostNetwork] = staticPorts
				}
			}

			if port.To < -1 {
				err := fmt.Errorf("Port %q cannot be mapped to negative value %d", port.Label, port.To)
				mErr.Errors = append(mErr.Errors, err)
			} else if port.To > math.MaxUint16 {
				err := fmt.Errorf("Port %q cannot be mapped to a port (%d) greater than %d", port.Label, port.To, math.MaxUint16)
				mErr.Errors = append(mErr.Errors, err)
			}
		}
	}
	// Check for duplicate tasks or port labels, and no duplicated static ports
	for _, task := range tg.Tasks {
		if task.Resources == nil {
			continue
		}

		for _, net := range task.Resources.Networks {
			for _, port := range append(net.ReservedPorts, net.DynamicPorts...) {
				if other, ok := portLabels[port.Label]; ok {
					mErr.Errors = append(mErr.Errors, fmt.Errorf("Port label %s already in use by %s", port.Label, other))
				}

				if port.Value != 0 {
					hostNetwork := port.HostNetwork
					if hostNetwork == "" {
						hostNetwork = "default"
					}
					staticPorts, ok := staticPortsIndex[hostNetwork]
					if !ok {
						staticPorts = make(map[int]string)
					}
					if other, ok := staticPorts[port.Value]; ok {
						err := fmt.Errorf("Static port %d already reserved by %s", port.Value, other)
						mErr.Errors = append(mErr.Errors, err)
					} else if port.Value > math.MaxUint16 {
						err := fmt.Errorf("Port %s (%d) cannot be greater than %d", port.Label, port.Value, math.MaxUint16)
						mErr.Errors = append(mErr.Errors, err)
					} else {
						staticPorts[port.Value] = fmt.Sprintf("%s:%s", task.Name, port.Label)
						staticPortsIndex[hostNetwork] = staticPorts
					}
				}
			}
		}
	}
	return mErr.ErrorOrNil()
}

// validateServices runs Service.Validate() on group-level services,
// checks that group services do not conflict with task services and that
// group service checks that refer to tasks only refer to tasks that exist.
func (tg *TaskGroup) validateServices() error {
	var mErr multierror.Error
	knownTasks := make(map[string]struct{})
	knownServices := make(map[string]struct{})

	// Create a map of known tasks and their services so we can compare
	// vs the group-level services and checks
	for _, task := range tg.Tasks {
		knownTasks[task.Name] = struct{}{}
		if task.Services == nil {
			continue
		}
		for _, service := range task.Services {
			if _, ok := knownServices[service.Name+service.PortLabel]; ok {
				mErr.Errors = append(mErr.Errors, fmt.Errorf("Service %s is duplicate", service.Name))
			}
			for _, check := range service.Checks {
				if check.TaskName != "" {
					mErr.Errors = append(mErr.Errors, fmt.Errorf("Check %s is invalid: only task group service checks can be assigned tasks", check.Name))
				}
			}
			knownServices[service.Name+service.PortLabel] = struct{}{}
		}
	}
	for i, service := range tg.Services {
		if err := service.Validate(); err != nil {
			outer := fmt.Errorf("Service[%d] %s validation failed: %s", i, service.Name, err)
			mErr.Errors = append(mErr.Errors, outer)
			// we break here to avoid the risk of crashing on null-pointer
			// access in a later step, accepting that we might miss out on
			// error messages to provide the user.
			continue
		}
		if service.AddressMode == AddressModeDriver {
			mErr.Errors = append(mErr.Errors, fmt.Errorf("service %q cannot use address_mode=\"driver\", only services defined in a \"task\" block can use this mode", service.Name))
		}
		if _, ok := knownServices[service.Name+service.PortLabel]; ok {
			mErr.Errors = append(mErr.Errors, fmt.Errorf("Service %s is duplicate", service.Name))
		}
		knownServices[service.Name+service.PortLabel] = struct{}{}
		for _, check := range service.Checks {
			if check.TaskName != "" {
				if check.Type != ServiceCheckScript && check.Type != ServiceCheckGRPC {
					mErr.Errors = append(mErr.Errors,
						fmt.Errorf("Check %s invalid: only script and gRPC checks should have tasks", check.Name))
				}
				if check.AddressMode == AddressModeDriver {
					mErr.Errors = append(mErr.Errors, fmt.Errorf("Check %q invalid: cannot use address_mode=\"driver\", only checks defined in a \"task\" service block can use this mode", service.Name))
				}
				if _, ok := knownTasks[check.TaskName]; !ok {
					mErr.Errors = append(mErr.Errors,
						fmt.Errorf("Check %s invalid: refers to non-existent task %s", check.Name, check.TaskName))
				}
			}
		}
	}
	return mErr.ErrorOrNil()
}

// validateScriptChecksInGroupServices ensures group-level services with script
// checks know what task driver to use. Either the service.task or service.check.task
// parameter must be configured.
func (tg *TaskGroup) validateScriptChecksInGroupServices() error {
	var mErr multierror.Error
	for _, service := range tg.Services {
		if service.TaskName == "" {
			for _, check := range service.Checks {
				if check.Type == "script" && check.TaskName == "" {
					mErr.Errors = append(mErr.Errors,
						fmt.Errorf("Service [%s]->%s or Check %s must specify task parameter",
							tg.Name, service.Name, check.Name,
						))
				}
			}
		}
	}
	return mErr.ErrorOrNil()
}

// validateScalingPolicy ensures that the scaling policy has consistent
// min and max, not in conflict with the task group count
func (tg *TaskGroup) validateScalingPolicy(j *Job) error {
	if tg.Scaling == nil {
		return nil
	}

	var mErr multierror.Error

	err := tg.Scaling.Validate()
	if err != nil {
		// prefix scaling policy errors
		if me, ok := err.(*multierror.Error); ok {
			for _, e := range me.Errors {
				mErr.Errors = append(mErr.Errors, fmt.Errorf("Scaling policy invalid: %s", e))
			}
		}
	}

	if tg.Scaling.Max < int64(tg.Count) {
		mErr.Errors = append(mErr.Errors,
			fmt.Errorf("Scaling policy invalid: task group count must not be greater than maximum count in scaling policy"))
	}

	if int64(tg.Count) < tg.Scaling.Min && !(j.IsMultiregion() && tg.Count == 0 && j.Region == "global") {
		mErr.Errors = append(mErr.Errors,
			fmt.Errorf("Scaling policy invalid: task group count must not be less than minimum count in scaling policy"))
	}

	return mErr.ErrorOrNil()
}

// Warnings returns a list of warnings that may be from dubious settings or
// deprecation warnings.
func (tg *TaskGroup) Warnings(j *Job) error {
	var mErr multierror.Error

	// Validate the update strategy
	if u := tg.Update; u != nil {
		// Check the counts are appropriate
		if u.MaxParallel > tg.Count && !(j.IsMultiregion() && tg.Count == 0) {
			mErr.Errors = append(mErr.Errors,
				fmt.Errorf("Update max parallel count is greater than task group count (%d > %d). "+
					"A destructive change would result in the simultaneous replacement of all allocations.", u.MaxParallel, tg.Count))
		}
	}

	// Check for mbits network field
	if len(tg.Networks) > 0 && tg.Networks[0].MBits > 0 {
		mErr.Errors = append(mErr.Errors, fmt.Errorf("mbits has been deprecated as of Nomad 0.12.0. Please remove mbits from the network block"))
	}

	for _, t := range tg.Tasks {
		if err := t.Warnings(); err != nil {
			err = multierror.Prefix(err, fmt.Sprintf("Task %q:", t.Name))
			mErr.Errors = append(mErr.Errors, err)
		}
	}

	return mErr.ErrorOrNil()
}

// LookupTask finds a task by name
func (tg *TaskGroup) LookupTask(name string) *Task {
	for _, t := range tg.Tasks {
		if t.Name == name {
			return t
		}
	}
	return nil
}

// UsesConnect for convenience returns true if the TaskGroup contains at least
// one service that makes use of Consul Connect features.
//
// Currently used for validating that the task group contains one or more connect
// aware services before generating a service identity token.
func (tg *TaskGroup) UsesConnect() bool {
	for _, service := range tg.Services {
		if service.Connect != nil {
			if service.Connect.IsNative() || service.Connect.HasSidecar() || service.Connect.IsGateway() {
				return true
			}
		}
	}
	return false
}

// UsesConnectGateway for convenience returns true if the TaskGroup contains at
// least one service that makes use of Consul Connect Gateway features.
func (tg *TaskGroup) UsesConnectGateway() bool {
	for _, service := range tg.Services {
		if service.Connect != nil {
			if service.Connect.IsGateway() {
				return true
			}
		}
	}
	return false
}

func (tg *TaskGroup) GoString() string {
	return fmt.Sprintf("*%#v", *tg)
}

// CheckRestart describes if and when a task should be restarted based on
// failing health checks.
type CheckRestart struct {
	Limit          int           // Restart task after this many unhealthy intervals
	Grace          time.Duration // Grace time to give tasks after starting to get healthy
	IgnoreWarnings bool          // If true treat checks in `warning` as passing
}

func (c *CheckRestart) Copy() *CheckRestart {
	if c == nil {
		return nil
	}

	nc := new(CheckRestart)
	*nc = *c
	return nc
}

func (c *CheckRestart) Equals(o *CheckRestart) bool {
	if c == nil || o == nil {
		return c == o
	}

	if c.Limit != o.Limit {
		return false
	}

	if c.Grace != o.Grace {
		return false
	}

	if c.IgnoreWarnings != o.IgnoreWarnings {
		return false
	}

	return true
}

func (c *CheckRestart) Validate() error {
	if c == nil {
		return nil
	}

	var mErr multierror.Error
	if c.Limit < 0 {
		mErr.Errors = append(mErr.Errors, fmt.Errorf("limit must be greater than or equal to 0 but found %d", c.Limit))
	}

	if c.Grace < 0 {
		mErr.Errors = append(mErr.Errors, fmt.Errorf("grace period must be greater than or equal to 0 but found %d", c.Grace))
	}

	return mErr.ErrorOrNil()
}

const (
	// DefaultKillTimeout is the default timeout between signaling a task it
	// will be killed and killing it.
	DefaultKillTimeout = 5 * time.Second
)

// LogConfig provides configuration for log rotation
type LogConfig struct {
	MaxFiles      int
	MaxFileSizeMB int
}

func (l *LogConfig) Equals(o *LogConfig) bool {
	if l == nil || o == nil {
		return l == o
	}

	if l.MaxFiles != o.MaxFiles {
		return false
	}

	if l.MaxFileSizeMB != o.MaxFileSizeMB {
		return false
	}

	return true
}

func (l *LogConfig) Copy() *LogConfig {
	if l == nil {
		return nil
	}
	return &LogConfig{
		MaxFiles:      l.MaxFiles,
		MaxFileSizeMB: l.MaxFileSizeMB,
	}
}

// DefaultLogConfig returns the default LogConfig values.
func DefaultLogConfig() *LogConfig {
	return &LogConfig{
		MaxFiles:      10,
		MaxFileSizeMB: 10,
	}
}

// Validate returns an error if the log config specified are less than
// the minimum allowed.
func (l *LogConfig) Validate() error {
	var mErr multierror.Error
	if l.MaxFiles < 1 {
		mErr.Errors = append(mErr.Errors, fmt.Errorf("minimum number of files is 1; got %d", l.MaxFiles))
	}
	if l.MaxFileSizeMB < 1 {
		mErr.Errors = append(mErr.Errors, fmt.Errorf("minimum file size is 1MB; got %d", l.MaxFileSizeMB))
	}
	return mErr.ErrorOrNil()
}

// Task is a single process typically that is executed as part of a task group.
type Task struct {
	// Name of the task
	Name string

	// Driver is used to control which driver is used
	Driver string

	// User is used to determine which user will run the task. It defaults to
	// the same user the Nomad client is being run as.
	User string

	// Config is provided to the driver to initialize
	Config map[string]interface{}

	// Map of environment variables to be used by the driver
	Env map[string]string

	// List of service definitions exposed by the Task
	Services []*Service

	// Vault is used to define the set of Vault policies that this task should
	// have access to.
	Vault *Vault

	// Templates are the set of templates to be rendered for the task.
	Templates []*Template

	// Constraints can be specified at a task level and apply only to
	// the particular task.
	Constraints []*Constraint

	// Affinities can be specified at the task level to express
	// scheduling preferences
	Affinities []*Affinity

	// Resources is the resources needed by this task
	Resources *Resources

	// RestartPolicy of a TaskGroup
	RestartPolicy *RestartPolicy

	// DispatchPayload configures how the task retrieves its input from a dispatch
	DispatchPayload *DispatchPayloadConfig

	Lifecycle *TaskLifecycleConfig

	// Meta is used to associate arbitrary metadata with this
	// task. This is opaque to Nomad.
	Meta map[string]string

	// KillTimeout is the time between signaling a task that it will be
	// killed and killing it.
	KillTimeout time.Duration

	// LogConfig provides configuration for log rotation
	LogConfig *LogConfig

	// Artifacts is a list of artifacts to download and extract before running
	// the task.
	Artifacts []*TaskArtifact

	// Leader marks the task as the leader within the group. When the leader
	// task exits, other tasks will be gracefully terminated.
	Leader bool

	// ShutdownDelay is the duration of the delay between deregistering a
	// task from Consul and sending it a signal to shutdown. See #2441
	ShutdownDelay time.Duration

	// VolumeMounts is a list of Volume name <-> mount configurations that will be
	// attached to this task.
	VolumeMounts []*VolumeMount

	// ScalingPolicies is a list of scaling policies scoped to this task
	ScalingPolicies []*ScalingPolicy

	// KillSignal is the kill signal to use for the task. This is an optional
	// specification and defaults to SIGINT
	KillSignal string

	// Used internally to manage tasks according to their TaskKind. Initial use case
	// is for Consul Connect
	Kind TaskKind

	// CSIPluginConfig is used to configure the plugin supervisor for the task.
	CSIPluginConfig *TaskCSIPluginConfig
}

// UsesConnect is for conveniently detecting if the Task is able to make use
// of Consul Connect features. This will be indicated in the TaskKind of the
// Task, which exports known types of Tasks. UsesConnect will be true if the
// task is a connect proxy, connect native, or is a connect gateway.
func (t *Task) UsesConnect() bool {
	return t.Kind.IsConnectNative() || t.UsesConnectSidecar()
}

func (t *Task) UsesConnectSidecar() bool {
	return t.Kind.IsConnectProxy() || t.Kind.IsAnyConnectGateway()
}

func (t *Task) Copy() *Task {
	if t == nil {
		return nil
	}
	nt := new(Task)
	*nt = *t
	nt.Env = helper.CopyMapStringString(nt.Env)

	if t.Services != nil {
		services := make([]*Service, len(nt.Services))
		for i, s := range nt.Services {
			services[i] = s.Copy()
		}
		nt.Services = services
	}

	nt.Constraints = CopySliceConstraints(nt.Constraints)
	nt.Affinities = CopySliceAffinities(nt.Affinities)
	nt.VolumeMounts = CopySliceVolumeMount(nt.VolumeMounts)
	nt.CSIPluginConfig = nt.CSIPluginConfig.Copy()

	nt.Vault = nt.Vault.Copy()
	nt.Resources = nt.Resources.Copy()
	nt.LogConfig = nt.LogConfig.Copy()
	nt.Meta = helper.CopyMapStringString(nt.Meta)
	nt.DispatchPayload = nt.DispatchPayload.Copy()
	nt.Lifecycle = nt.Lifecycle.Copy()

	if t.Artifacts != nil {
		artifacts := make([]*TaskArtifact, 0, len(t.Artifacts))
		for _, a := range nt.Artifacts {
			artifacts = append(artifacts, a.Copy())
		}
		nt.Artifacts = artifacts
	}

	if i, err := copystructure.Copy(nt.Config); err != nil {
		panic(err.Error())
	} else {
		nt.Config = i.(map[string]interface{})
	}

	if t.Templates != nil {
		templates := make([]*Template, len(t.Templates))
		for i, tmpl := range nt.Templates {
			templates[i] = tmpl.Copy()
		}
		nt.Templates = templates
	}

	return nt
}

// Canonicalize canonicalizes fields in the task.
func (t *Task) Canonicalize(job *Job, tg *TaskGroup) {
	// Ensure that an empty and nil map are treated the same to avoid scheduling
	// problems since we use reflect DeepEquals.
	if len(t.Meta) == 0 {
		t.Meta = nil
	}
	if len(t.Config) == 0 {
		t.Config = nil
	}
	if len(t.Env) == 0 {
		t.Env = nil
	}

	for _, service := range t.Services {
		service.Canonicalize(job.Name, tg.Name, t.Name)
	}

	// If Resources are nil initialize them to defaults, otherwise canonicalize
	if t.Resources == nil {
		t.Resources = DefaultResources()
	} else {
		t.Resources.Canonicalize()
	}

	if t.RestartPolicy == nil {
		t.RestartPolicy = tg.RestartPolicy
	}

	// Set the default timeout if it is not specified.
	if t.KillTimeout == 0 {
		t.KillTimeout = DefaultKillTimeout
	}

	if t.Vault != nil {
		t.Vault.Canonicalize()
	}

	for _, template := range t.Templates {
		template.Canonicalize()
	}
}

func (t *Task) GoString() string {
	return fmt.Sprintf("*%#v", *t)
}

// Validate is used to sanity check a task
func (t *Task) Validate(ephemeralDisk *EphemeralDisk, jobType string, tgServices []*Service, tgNetworks Networks) error {
	var mErr multierror.Error
	if t.Name == "" {
		mErr.Errors = append(mErr.Errors, errors.New("Missing task name"))
	}
	if strings.ContainsAny(t.Name, `/\`) {
		// We enforce this so that when creating the directory on disk it will
		// not have any slashes.
		mErr.Errors = append(mErr.Errors, errors.New("Task name cannot include slashes"))
	} else if strings.Contains(t.Name, "\000") {
		mErr.Errors = append(mErr.Errors, errors.New("Task name cannot include null characters"))
	}
	if t.Driver == "" {
		mErr.Errors = append(mErr.Errors, errors.New("Missing task driver"))
	}
	if t.KillTimeout < 0 {
		mErr.Errors = append(mErr.Errors, errors.New("KillTimeout must be a positive value"))
	}
	if t.ShutdownDelay < 0 {
		mErr.Errors = append(mErr.Errors, errors.New("ShutdownDelay must be a positive value"))
	}

	// Validate the resources.
	if t.Resources == nil {
		mErr.Errors = append(mErr.Errors, errors.New("Missing task resources"))
	} else if err := t.Resources.Validate(); err != nil {
		mErr.Errors = append(mErr.Errors, err)
	}

	// Validate the log config
	if t.LogConfig == nil {
		mErr.Errors = append(mErr.Errors, errors.New("Missing Log Config"))
	} else if err := t.LogConfig.Validate(); err != nil {
		mErr.Errors = append(mErr.Errors, err)
	}

	for idx, constr := range t.Constraints {
		if err := constr.Validate(); err != nil {
			outer := fmt.Errorf("Constraint %d validation failed: %s", idx+1, err)
			mErr.Errors = append(mErr.Errors, outer)
		}

		switch constr.Operand {
		case ConstraintDistinctHosts, ConstraintDistinctProperty:
			outer := fmt.Errorf("Constraint %d has disallowed Operand at task level: %s", idx+1, constr.Operand)
			mErr.Errors = append(mErr.Errors, outer)
		}
	}

	if jobType == JobTypeSystem {
		if t.Affinities != nil {
			mErr.Errors = append(mErr.Errors, fmt.Errorf("System jobs may not have an affinity stanza"))
		}
	} else {
		for idx, affinity := range t.Affinities {
			if err := affinity.Validate(); err != nil {
				outer := fmt.Errorf("Affinity %d validation failed: %s", idx+1, err)
				mErr.Errors = append(mErr.Errors, outer)
			}
		}
	}

	// Validate Services
	if err := validateServices(t, tgNetworks); err != nil {
		mErr.Errors = append(mErr.Errors, err)
	}

	if t.LogConfig != nil && ephemeralDisk != nil {
		logUsage := (t.LogConfig.MaxFiles * t.LogConfig.MaxFileSizeMB)
		if ephemeralDisk.SizeMB <= logUsage {
			mErr.Errors = append(mErr.Errors,
				fmt.Errorf("log storage (%d MB) must be less than requested disk capacity (%d MB)",
					logUsage, ephemeralDisk.SizeMB))
		}
	}

	for idx, artifact := range t.Artifacts {
		if err := artifact.Validate(); err != nil {
			outer := fmt.Errorf("Artifact %d validation failed: %v", idx+1, err)
			mErr.Errors = append(mErr.Errors, outer)
		}
	}

	if t.Vault != nil {
		if err := t.Vault.Validate(); err != nil {
			mErr.Errors = append(mErr.Errors, fmt.Errorf("Vault validation failed: %v", err))
		}
	}

	destinations := make(map[string]int, len(t.Templates))
	for idx, tmpl := range t.Templates {
		if err := tmpl.Validate(); err != nil {
			outer := fmt.Errorf("Template %d validation failed: %s", idx+1, err)
			mErr.Errors = append(mErr.Errors, outer)
		}

		if other, ok := destinations[tmpl.DestPath]; ok {
			outer := fmt.Errorf("Template %d has same destination as %d", idx+1, other)
			mErr.Errors = append(mErr.Errors, outer)
		} else {
			destinations[tmpl.DestPath] = idx + 1
		}
	}

	// Validate the dispatch payload block if there
	if t.DispatchPayload != nil {
		if err := t.DispatchPayload.Validate(); err != nil {
			mErr.Errors = append(mErr.Errors, fmt.Errorf("Dispatch Payload validation failed: %v", err))
		}
	}

	// Validate the Lifecycle block if there
	if t.Lifecycle != nil {
		if err := t.Lifecycle.Validate(); err != nil {
			mErr.Errors = append(mErr.Errors, fmt.Errorf("Lifecycle validation failed: %v", err))
		}

	}

	// Validation for TaskKind field which is used for Consul Connect integration
	if t.Kind.IsConnectProxy() {
		// This task is a Connect proxy so it should not have service stanzas
		if len(t.Services) > 0 {
			mErr.Errors = append(mErr.Errors, fmt.Errorf("Connect proxy task must not have a service stanza"))
		}
		if t.Leader {
			mErr.Errors = append(mErr.Errors, fmt.Errorf("Connect proxy task must not have leader set"))
		}

		// Ensure the proxy task has a corresponding service entry
		serviceErr := ValidateConnectProxyService(t.Kind.Value(), tgServices)
		if serviceErr != nil {
			mErr.Errors = append(mErr.Errors, serviceErr)
		}
	}

	// Validation for volumes
	for idx, vm := range t.VolumeMounts {
		if !MountPropagationModeIsValid(vm.PropagationMode) {
			mErr.Errors = append(mErr.Errors, fmt.Errorf("Volume Mount (%d) has an invalid propagation mode: \"%s\"", idx, vm.PropagationMode))
		}
	}

	// Validate CSI Plugin Config
	if t.CSIPluginConfig != nil {
		if t.CSIPluginConfig.ID == "" {
			mErr.Errors = append(mErr.Errors, fmt.Errorf("CSIPluginConfig must have a non-empty PluginID"))
		}

		if !CSIPluginTypeIsValid(t.CSIPluginConfig.Type) {
			mErr.Errors = append(mErr.Errors, fmt.Errorf("CSIPluginConfig PluginType must be one of 'node', 'controller', or 'monolith', got: \"%s\"", t.CSIPluginConfig.Type))
		}

		// TODO: Investigate validation of the PluginMountDir. Not much we can do apart from check IsAbs until after we understand its execution environment though :(
	}

	return mErr.ErrorOrNil()
}

// validateServices takes a task and validates the services within it are valid
// and reference ports that exist.
func validateServices(t *Task, tgNetworks Networks) error {
	var mErr multierror.Error

	// Ensure that services don't ask for nonexistent ports and their names are
	// unique.
	servicePorts := make(map[string]map[string]struct{})
	addServicePort := func(label, service string) {
		if _, ok := servicePorts[label]; !ok {
			servicePorts[label] = map[string]struct{}{}
		}
		servicePorts[label][service] = struct{}{}
	}
	knownServices := make(map[string]struct{})
	for i, service := range t.Services {
		if err := service.Validate(); err != nil {
			outer := fmt.Errorf("service[%d] %+q validation failed: %s", i, service.Name, err)
			mErr.Errors = append(mErr.Errors, outer)
		}

		if service.AddressMode == AddressModeAlloc {
			mErr.Errors = append(mErr.Errors, fmt.Errorf("service %q cannot use address_mode=\"alloc\", only services defined in a \"group\" block can use this mode", service.Name))
		}

		// Ensure that services with the same name are not being registered for
		// the same port
		if _, ok := knownServices[service.Name+service.PortLabel]; ok {
			mErr.Errors = append(mErr.Errors, fmt.Errorf("service %q is duplicate", service.Name))
		}
		knownServices[service.Name+service.PortLabel] = struct{}{}

		if service.PortLabel != "" {
			if service.AddressMode == "driver" {
				// Numeric port labels are valid for address_mode=driver
				_, err := strconv.Atoi(service.PortLabel)
				if err != nil {
					// Not a numeric port label, add it to list to check
					addServicePort(service.PortLabel, service.Name)
				}
			} else {
				addServicePort(service.PortLabel, service.Name)
			}
		}

		// connect block is only allowed on group level
		if service.Connect != nil {
			mErr.Errors = append(mErr.Errors, fmt.Errorf("service %q cannot have \"connect\" block, only services defined in a \"group\" block can", service.Name))
		}

		// Ensure that check names are unique and have valid ports
		knownChecks := make(map[string]struct{})
		for _, check := range service.Checks {
			if _, ok := knownChecks[check.Name]; ok {
				mErr.Errors = append(mErr.Errors, fmt.Errorf("check %q is duplicate", check.Name))
			}
			knownChecks[check.Name] = struct{}{}

			if check.AddressMode == AddressModeAlloc {
				mErr.Errors = append(mErr.Errors, fmt.Errorf("check %q cannot use address_mode=\"alloc\", only checks defined in a \"group\" service block can use this mode", service.Name))
			}

			if !check.RequiresPort() {
				// No need to continue validating check if it doesn't need a port
				continue
			}

			effectivePort := check.PortLabel
			if effectivePort == "" {
				// Inherits from service
				effectivePort = service.PortLabel
			}

			if effectivePort == "" {
				mErr.Errors = append(mErr.Errors, fmt.Errorf("check %q is missing a port", check.Name))
				continue
			}

			isNumeric := false
			portNumber, err := strconv.Atoi(effectivePort)
			if err == nil {
				isNumeric = true
			}

			// Numeric ports are fine for address_mode = "driver"
			if check.AddressMode == "driver" && isNumeric {
				if portNumber <= 0 {
					mErr.Errors = append(mErr.Errors, fmt.Errorf("check %q has invalid numeric port %d", check.Name, portNumber))
				}
				continue
			}

			if isNumeric {
				mErr.Errors = append(mErr.Errors, fmt.Errorf(`check %q cannot use a numeric port %d without setting address_mode="driver"`, check.Name, portNumber))
				continue
			}

			// PortLabel must exist, report errors by its parent service
			addServicePort(effectivePort, service.Name)
		}
	}

	// Get the set of group port labels.
	portLabels := make(map[string]struct{})
	if len(tgNetworks) > 0 {
		ports := tgNetworks[0].PortLabels()
		for portLabel := range ports {
			portLabels[portLabel] = struct{}{}
		}
	}

	// COMPAT(0.13)
	// Append the set of task port labels. (Note that network resources on the
	// task resources are deprecated, but we must let them continue working; a
	// warning will be emitted on job submission).
	if t.Resources != nil {
		for _, network := range t.Resources.Networks {
			for portLabel := range network.PortLabels() {
				portLabels[portLabel] = struct{}{}
			}
		}
	}

	// Iterate over a sorted list of keys to make error listings stable
	keys := make([]string, 0, len(servicePorts))
	for p := range servicePorts {
		keys = append(keys, p)
	}
	sort.Strings(keys)

	// Ensure all ports referenced in services exist.
	for _, servicePort := range keys {
		services := servicePorts[servicePort]
		_, ok := portLabels[servicePort]
		if !ok {
			names := make([]string, 0, len(services))
			for name := range services {
				names = append(names, name)
			}

			// Keep order deterministic
			sort.Strings(names)
			joined := strings.Join(names, ", ")
			err := fmt.Errorf("port label %q referenced by services %v does not exist", servicePort, joined)
			mErr.Errors = append(mErr.Errors, err)
		}
	}

	// Ensure address mode is valid
	return mErr.ErrorOrNil()
}

func (t *Task) Warnings() error {
	var mErr multierror.Error

	// Validate the resources
	if t.Resources != nil && t.Resources.IOPS != 0 {
		mErr.Errors = append(mErr.Errors, fmt.Errorf("IOPS has been deprecated as of Nomad 0.9.0. Please remove IOPS from resource stanza."))
	}

	if t.Resources != nil && len(t.Resources.Networks) != 0 {
		mErr.Errors = append(mErr.Errors, fmt.Errorf("task network resources have been deprecated as of Nomad 0.12.0. Please configure networking via group network block."))
	}

	for idx, tmpl := range t.Templates {
		if err := tmpl.Warnings(); err != nil {
			err = multierror.Prefix(err, fmt.Sprintf("Template[%d]", idx))
			mErr.Errors = append(mErr.Errors, err)
		}
	}

	return mErr.ErrorOrNil()
}

// TaskKind identifies the special kinds of tasks using the following format:
// '<kind_name>(:<identifier>)`. The TaskKind can optionally include an identifier that
// is opaque to the Task. This identifier can be used to relate the task to some
// other entity based on the kind.
//
// For example, a task may have the TaskKind of `connect-proxy:service` where
// 'connect-proxy' is the kind name and 'service' is the identifier that relates the
// task to the service name of which it is a connect proxy for.
type TaskKind string

func NewTaskKind(name, identifier string) TaskKind {
	return TaskKind(fmt.Sprintf("%s:%s", name, identifier))
}

// Name returns the kind name portion of the TaskKind
func (k TaskKind) Name() string {
	return strings.Split(string(k), ":")[0]
}

// Value returns the identifier of the TaskKind or an empty string if it doesn't
// include one.
func (k TaskKind) Value() string {
	if s := strings.SplitN(string(k), ":", 2); len(s) > 1 {
		return s[1]
	}
	return ""
}

func (k TaskKind) hasPrefix(prefix string) bool {
	return strings.HasPrefix(string(k), prefix+":") && len(k) > len(prefix)+1
}

// IsConnectProxy returns true if the TaskKind is connect-proxy.
func (k TaskKind) IsConnectProxy() bool {
	return k.hasPrefix(ConnectProxyPrefix)
}

// IsConnectNative returns true if the TaskKind is connect-native.
func (k TaskKind) IsConnectNative() bool {
	return k.hasPrefix(ConnectNativePrefix)
}

func (k TaskKind) IsConnectIngress() bool {
	return k.hasPrefix(ConnectIngressPrefix)
}

func (k TaskKind) IsConnectTerminating() bool {
	return k.hasPrefix(ConnectTerminatingPrefix)
}

func (k TaskKind) IsAnyConnectGateway() bool {
	switch {
	case k.IsConnectIngress():
		return true
	case k.IsConnectTerminating():
		return true
	default:
		return false
	}
}

const (
	// ConnectProxyPrefix is the prefix used for fields referencing a Consul Connect
	// Proxy
	ConnectProxyPrefix = "connect-proxy"

	// ConnectNativePrefix is the prefix used for fields referencing a Connect
	// Native Task
	ConnectNativePrefix = "connect-native"

	// ConnectIngressPrefix is the prefix used for fields referencing a Consul
	// Connect Ingress Gateway Proxy.
	ConnectIngressPrefix = "connect-ingress"

	// ConnectTerminatingPrefix is the prefix used for fields referencing a Consul
	// Connect Terminating Gateway Proxy.
	//
	ConnectTerminatingPrefix = "connect-terminating"

	// ConnectMeshPrefix is the prefix used for fields referencing a Consul Connect
	// Mesh Gateway Proxy.
	//
	// Not yet supported.
	// ConnectMeshPrefix = "connect-mesh"
)

// ValidateConnectProxyService checks that the service that is being
// proxied by this task exists in the task group and contains
// valid Connect config.
func ValidateConnectProxyService(serviceName string, tgServices []*Service) error {
	found := false
	names := make([]string, 0, len(tgServices))
	for _, svc := range tgServices {
		if svc.Connect == nil || svc.Connect.SidecarService == nil {
			continue
		}

		if svc.Name == serviceName {
			found = true
			break
		}

		// Build up list of mismatched Connect service names for error
		// reporting.
		names = append(names, svc.Name)
	}

	if !found {
		if len(names) == 0 {
			return fmt.Errorf("No Connect services in task group with Connect proxy (%q)", serviceName)
		} else {
			return fmt.Errorf("Connect proxy service name (%q) not found in Connect services from task group: %s", serviceName, names)
		}
	}

	return nil
}

const (
	// TemplateChangeModeNoop marks that no action should be taken if the
	// template is re-rendered
	TemplateChangeModeNoop = "noop"

	// TemplateChangeModeSignal marks that the task should be signaled if the
	// template is re-rendered
	TemplateChangeModeSignal = "signal"

	// TemplateChangeModeRestart marks that the task should be restarted if the
	// template is re-rendered
	TemplateChangeModeRestart = "restart"
)

var (
	// TemplateChangeModeInvalidError is the error for when an invalid change
	// mode is given
	TemplateChangeModeInvalidError = errors.New("Invalid change mode. Must be one of the following: noop, signal, restart")
)

// Template represents a template configuration to be rendered for a given task
type Template struct {
	// SourcePath is the path to the template to be rendered
	SourcePath string

	// DestPath is the path to where the template should be rendered
	DestPath string

	// EmbeddedTmpl store the raw template. This is useful for smaller templates
	// where they are embedded in the job file rather than sent as an artifact
	EmbeddedTmpl string

	// ChangeMode indicates what should be done if the template is re-rendered
	ChangeMode string

	// ChangeSignal is the signal that should be sent if the change mode
	// requires it.
	ChangeSignal string

	// Splay is used to avoid coordinated restarts of processes by applying a
	// random wait between 0 and the given splay value before signalling the
	// application of a change
	Splay time.Duration

	// Perms is the permission the file should be written out with.
	Perms string

	// LeftDelim and RightDelim are optional configurations to control what
	// delimiter is utilized when parsing the template.
	LeftDelim  string
	RightDelim string

	// Envvars enables exposing the template as environment variables
	// instead of as a file. The template must be of the form:
	//
	//	VAR_NAME_1={{ key service/my-key }}
	//	VAR_NAME_2=raw string and {{ env "attr.kernel.name" }}
	//
	// Lines will be split on the initial "=" with the first part being the
	// key name and the second part the value.
	// Empty lines and lines starting with # will be ignored, but to avoid
	// escaping issues #s within lines will not be treated as comments.
	Envvars bool

	// VaultGrace is the grace duration between lease renewal and reacquiring a
	// secret. If the lease of a secret is less than the grace, a new secret is
	// acquired.
	// COMPAT(0.12) VaultGrace has been ignored by Vault since Vault v0.5.
	VaultGrace time.Duration
}

// DefaultTemplate returns a default template.
func DefaultTemplate() *Template {
	return &Template{
		ChangeMode: TemplateChangeModeRestart,
		Splay:      5 * time.Second,
		Perms:      "0644",
	}
}

func (t *Template) Copy() *Template {
	if t == nil {
		return nil
	}
	copy := new(Template)
	*copy = *t
	return copy
}

func (t *Template) Canonicalize() {
	if t.ChangeSignal != "" {
		t.ChangeSignal = strings.ToUpper(t.ChangeSignal)
	}
}

func (t *Template) Validate() error {
	var mErr multierror.Error

	// Verify we have something to render
	if t.SourcePath == "" && t.EmbeddedTmpl == "" {
		_ = multierror.Append(&mErr, fmt.Errorf("Must specify a source path or have an embedded template"))
	}

	// Verify we can render somewhere
	if t.DestPath == "" {
		_ = multierror.Append(&mErr, fmt.Errorf("Must specify a destination for the template"))
	}

	// Verify the destination doesn't escape
	escaped, err := PathEscapesAllocDir("task", t.DestPath)
	if err != nil {
		mErr.Errors = append(mErr.Errors, fmt.Errorf("invalid destination path: %v", err))
	} else if escaped {
		mErr.Errors = append(mErr.Errors, fmt.Errorf("destination escapes allocation directory"))
	}

	// Verify a proper change mode
	switch t.ChangeMode {
	case TemplateChangeModeNoop, TemplateChangeModeRestart:
	case TemplateChangeModeSignal:
		if t.ChangeSignal == "" {
			_ = multierror.Append(&mErr, fmt.Errorf("Must specify signal value when change mode is signal"))
		}
		if t.Envvars {
			_ = multierror.Append(&mErr, fmt.Errorf("cannot use signals with env var templates"))
		}
	default:
		_ = multierror.Append(&mErr, TemplateChangeModeInvalidError)
	}

	// Verify the splay is positive
	if t.Splay < 0 {
		_ = multierror.Append(&mErr, fmt.Errorf("Must specify positive splay value"))
	}

	// Verify the permissions
	if t.Perms != "" {
		if _, err := strconv.ParseUint(t.Perms, 8, 12); err != nil {
			_ = multierror.Append(&mErr, fmt.Errorf("Failed to parse %q as octal: %v", t.Perms, err))
		}
	}

	return mErr.ErrorOrNil()
}

func (t *Template) Warnings() error {
	var mErr multierror.Error

	// Deprecation notice for vault_grace
	if t.VaultGrace != 0 {
		mErr.Errors = append(mErr.Errors, fmt.Errorf("VaultGrace has been deprecated as of Nomad 0.11 and ignored since Vault 0.5. Please remove VaultGrace / vault_grace from template stanza."))
	}

	return mErr.ErrorOrNil()
}

// AllocState records a single event that changes the state of the whole allocation
type AllocStateField uint8

const (
	AllocStateFieldClientStatus AllocStateField = iota
)

type AllocState struct {
	Field AllocStateField
	Value string
	Time  time.Time
}

// Set of possible states for a task.
const (
	TaskStatePending = "pending" // The task is waiting to be run.
	TaskStateRunning = "running" // The task is currently running.
	TaskStateDead    = "dead"    // Terminal state of task.
)

// TaskState tracks the current state of a task and events that caused state
// transitions.
type TaskState struct {
	// The current state of the task.
	State string

	// Failed marks a task as having failed
	Failed bool

	// Restarts is the number of times the task has restarted
	Restarts uint64

	// LastRestart is the time the task last restarted. It is updated each time the
	// task restarts
	LastRestart time.Time

	// StartedAt is the time the task is started. It is updated each time the
	// task starts
	StartedAt time.Time

	// FinishedAt is the time at which the task transitioned to dead and will
	// not be started again.
	FinishedAt time.Time

	// Series of task events that transition the state of the task.
	Events []*TaskEvent
}

// NewTaskState returns a TaskState initialized in the Pending state.
func NewTaskState() *TaskState {
	return &TaskState{
		State: TaskStatePending,
	}
}

// Canonicalize ensures the TaskState has a State set. It should default to
// Pending.
func (ts *TaskState) Canonicalize() {
	if ts.State == "" {
		ts.State = TaskStatePending
	}
}

func (ts *TaskState) Copy() *TaskState {
	if ts == nil {
		return nil
	}
	copy := new(TaskState)
	*copy = *ts

	if ts.Events != nil {
		copy.Events = make([]*TaskEvent, len(ts.Events))
		for i, e := range ts.Events {
			copy.Events[i] = e.Copy()
		}
	}
	return copy
}

// Successful returns whether a task finished successfully. This doesn't really
// have meaning on a non-batch allocation because a service and system
// allocation should not finish.
func (ts *TaskState) Successful() bool {
	return ts.State == TaskStateDead && !ts.Failed
}

const (
	// TaskSetupFailure indicates that the task could not be started due to a
	// a setup failure.
	TaskSetupFailure = "Setup Failure"

	// TaskDriveFailure indicates that the task could not be started due to a
	// failure in the driver. TaskDriverFailure is considered Recoverable.
	TaskDriverFailure = "Driver Failure"

	// TaskReceived signals that the task has been pulled by the client at the
	// given timestamp.
	TaskReceived = "Received"

	// TaskFailedValidation indicates the task was invalid and as such was not run.
	// TaskFailedValidation is not considered Recoverable.
	TaskFailedValidation = "Failed Validation"

	// TaskStarted signals that the task was started and its timestamp can be
	// used to determine the running length of the task.
	TaskStarted = "Started"

	// TaskTerminated indicates that the task was started and exited.
	TaskTerminated = "Terminated"

	// TaskKilling indicates a kill signal has been sent to the task.
	TaskKilling = "Killing"

	// TaskKilled indicates a user has killed the task.
	TaskKilled = "Killed"

	// TaskRestarting indicates that task terminated and is being restarted.
	TaskRestarting = "Restarting"

	// TaskNotRestarting indicates that the task has failed and is not being
	// restarted because it has exceeded its restart policy.
	TaskNotRestarting = "Not Restarting"

	// TaskRestartSignal indicates that the task has been signalled to be
	// restarted
	TaskRestartSignal = "Restart Signaled"

	// TaskSignaling indicates that the task is being signalled.
	TaskSignaling = "Signaling"

	// TaskDownloadingArtifacts means the task is downloading the artifacts
	// specified in the task.
	TaskDownloadingArtifacts = "Downloading Artifacts"

	// TaskArtifactDownloadFailed indicates that downloading the artifacts
	// failed.
	TaskArtifactDownloadFailed = "Failed Artifact Download"

	// TaskBuildingTaskDir indicates that the task directory/chroot is being
	// built.
	TaskBuildingTaskDir = "Building Task Directory"

	// TaskSetup indicates the task runner is setting up the task environment
	TaskSetup = "Task Setup"

	// TaskDiskExceeded indicates that one of the tasks in a taskgroup has
	// exceeded the requested disk resources.
	TaskDiskExceeded = "Disk Resources Exceeded"

	// TaskSiblingFailed indicates that a sibling task in the task group has
	// failed.
	TaskSiblingFailed = "Sibling Task Failed"

	// TaskDriverMessage is an informational event message emitted by
	// drivers such as when they're performing a long running action like
	// downloading an image.
	TaskDriverMessage = "Driver"

	// TaskLeaderDead indicates that the leader task within the has finished.
	TaskLeaderDead = "Leader Task Dead"

	// TaskMainDead indicates that the main tasks have dead
	TaskMainDead = "Main Tasks Dead"

	// TaskHookFailed indicates that one of the hooks for a task failed.
	TaskHookFailed = "Task hook failed"

	// TaskRestoreFailed indicates Nomad was unable to reattach to a
	// restored task.
	TaskRestoreFailed = "Failed Restoring Task"

	// TaskPluginUnhealthy indicates that a plugin managed by Nomad became unhealthy
	TaskPluginUnhealthy = "Plugin became unhealthy"

	// TaskPluginHealthy indicates that a plugin managed by Nomad became healthy
	TaskPluginHealthy = "Plugin became healthy"
)

// TaskEvent is an event that effects the state of a task and contains meta-data
// appropriate to the events type.
type TaskEvent struct {
	Type string
	Time int64 // Unix Nanosecond timestamp

	Message string // A possible message explaining the termination of the task.

	// DisplayMessage is a human friendly message about the event
	DisplayMessage string

	// Details is a map with annotated info about the event
	Details map[string]string

	// DEPRECATION NOTICE: The following fields are deprecated and will be removed
	// in a future release. Field values are available in the Details map.

	// FailsTask marks whether this event fails the task.
	// Deprecated, use Details["fails_task"] to access this.
	FailsTask bool

	// Restart fields.
	// Deprecated, use Details["restart_reason"] to access this.
	RestartReason string

	// Setup Failure fields.
	// Deprecated, use Details["setup_error"] to access this.
	SetupError string

	// Driver Failure fields.
	// Deprecated, use Details["driver_error"] to access this.
	DriverError string // A driver error occurred while starting the task.

	// Task Terminated Fields.

	// Deprecated, use Details["exit_code"] to access this.
	ExitCode int // The exit code of the task.

	// Deprecated, use Details["signal"] to access this.
	Signal int // The signal that terminated the task.

	// Killing fields
	// Deprecated, use Details["kill_timeout"] to access this.
	KillTimeout time.Duration

	// Task Killed Fields.
	// Deprecated, use Details["kill_error"] to access this.
	KillError string // Error killing the task.

	// KillReason is the reason the task was killed
	// Deprecated, use Details["kill_reason"] to access this.
	KillReason string

	// TaskRestarting fields.
	// Deprecated, use Details["start_delay"] to access this.
	StartDelay int64 // The sleep period before restarting the task in unix nanoseconds.

	// Artifact Download fields
	// Deprecated, use Details["download_error"] to access this.
	DownloadError string // Error downloading artifacts

	// Validation fields
	// Deprecated, use Details["validation_error"] to access this.
	ValidationError string // Validation error

	// The maximum allowed task disk size.
	// Deprecated, use Details["disk_limit"] to access this.
	DiskLimit int64

	// Name of the sibling task that caused termination of the task that
	// the TaskEvent refers to.
	// Deprecated, use Details["failed_sibling"] to access this.
	FailedSibling string

	// VaultError is the error from token renewal
	// Deprecated, use Details["vault_renewal_error"] to access this.
	VaultError string

	// TaskSignalReason indicates the reason the task is being signalled.
	// Deprecated, use Details["task_signal_reason"] to access this.
	TaskSignalReason string

	// TaskSignal is the signal that was sent to the task
	// Deprecated, use Details["task_signal"] to access this.
	TaskSignal string

	// DriverMessage indicates a driver action being taken.
	// Deprecated, use Details["driver_message"] to access this.
	DriverMessage string

	// GenericSource is the source of a message.
	// Deprecated, is redundant with event type.
	GenericSource string
}

func (event *TaskEvent) PopulateEventDisplayMessage() {
	// Build up the description based on the event type.
	if event == nil { //TODO(preetha) needs investigation alloc_runner's Run method sends a nil event when sigterming nomad. Why?
		return
	}

	if event.DisplayMessage != "" {
		return
	}

	var desc string
	switch event.Type {
	case TaskSetup:
		desc = event.Message
	case TaskStarted:
		desc = "Task started by client"
	case TaskReceived:
		desc = "Task received by client"
	case TaskFailedValidation:
		if event.ValidationError != "" {
			desc = event.ValidationError
		} else {
			desc = "Validation of task failed"
		}
	case TaskSetupFailure:
		if event.SetupError != "" {
			desc = event.SetupError
		} else {
			desc = "Task setup failed"
		}
	case TaskDriverFailure:
		if event.DriverError != "" {
			desc = event.DriverError
		} else {
			desc = "Failed to start task"
		}
	case TaskDownloadingArtifacts:
		desc = "Client is downloading artifacts"
	case TaskArtifactDownloadFailed:
		if event.DownloadError != "" {
			desc = event.DownloadError
		} else {
			desc = "Failed to download artifacts"
		}
	case TaskKilling:
		if event.KillReason != "" {
			desc = event.KillReason
		} else if event.KillTimeout != 0 {
			desc = fmt.Sprintf("Sent interrupt. Waiting %v before force killing", event.KillTimeout)
		} else {
			desc = "Sent interrupt"
		}
	case TaskKilled:
		if event.KillError != "" {
			desc = event.KillError
		} else {
			desc = "Task successfully killed"
		}
	case TaskTerminated:
		var parts []string
		parts = append(parts, fmt.Sprintf("Exit Code: %d", event.ExitCode))

		if event.Signal != 0 {
			parts = append(parts, fmt.Sprintf("Signal: %d", event.Signal))
		}

		if event.Message != "" {
			parts = append(parts, fmt.Sprintf("Exit Message: %q", event.Message))
		}
		desc = strings.Join(parts, ", ")
	case TaskRestarting:
		in := fmt.Sprintf("Task restarting in %v", time.Duration(event.StartDelay))
		if event.RestartReason != "" && event.RestartReason != ReasonWithinPolicy {
			desc = fmt.Sprintf("%s - %s", event.RestartReason, in)
		} else {
			desc = in
		}
	case TaskNotRestarting:
		if event.RestartReason != "" {
			desc = event.RestartReason
		} else {
			desc = "Task exceeded restart policy"
		}
	case TaskSiblingFailed:
		if event.FailedSibling != "" {
			desc = fmt.Sprintf("Task's sibling %q failed", event.FailedSibling)
		} else {
			desc = "Task's sibling failed"
		}
	case TaskSignaling:
		sig := event.TaskSignal
		reason := event.TaskSignalReason

		if sig == "" && reason == "" {
			desc = "Task being sent a signal"
		} else if sig == "" {
			desc = reason
		} else if reason == "" {
			desc = fmt.Sprintf("Task being sent signal %v", sig)
		} else {
			desc = fmt.Sprintf("Task being sent signal %v: %v", sig, reason)
		}
	case TaskRestartSignal:
		if event.RestartReason != "" {
			desc = event.RestartReason
		} else {
			desc = "Task signaled to restart"
		}
	case TaskDriverMessage:
		desc = event.DriverMessage
	case TaskLeaderDead:
		desc = "Leader Task in Group dead"
	case TaskMainDead:
		desc = "Main tasks in the group died"
	default:
		desc = event.Message
	}

	event.DisplayMessage = desc
}

func (te *TaskEvent) GoString() string {
	return fmt.Sprintf("%v - %v", te.Time, te.Type)
}

// SetDisplayMessage sets the display message of TaskEvent
func (te *TaskEvent) SetDisplayMessage(msg string) *TaskEvent {
	te.DisplayMessage = msg
	return te
}

// SetMessage sets the message of TaskEvent
func (te *TaskEvent) SetMessage(msg string) *TaskEvent {
	te.Message = msg
	te.Details["message"] = msg
	return te
}

func (te *TaskEvent) Copy() *TaskEvent {
	if te == nil {
		return nil
	}
	copy := new(TaskEvent)
	*copy = *te
	return copy
}

func NewTaskEvent(event string) *TaskEvent {
	return &TaskEvent{
		Type:    event,
		Time:    time.Now().UnixNano(),
		Details: make(map[string]string),
	}
}

// SetSetupError is used to store an error that occurred while setting up the
// task
func (e *TaskEvent) SetSetupError(err error) *TaskEvent {
	if err != nil {
		e.SetupError = err.Error()
		e.Details["setup_error"] = err.Error()
	}
	return e
}

func (e *TaskEvent) SetFailsTask() *TaskEvent {
	e.FailsTask = true
	e.Details["fails_task"] = "true"
	return e
}

func (e *TaskEvent) SetDriverError(err error) *TaskEvent {
	if err != nil {
		e.DriverError = err.Error()
		e.Details["driver_error"] = err.Error()
	}
	return e
}

func (e *TaskEvent) SetExitCode(c int) *TaskEvent {
	e.ExitCode = c
	e.Details["exit_code"] = fmt.Sprintf("%d", c)
	return e
}

func (e *TaskEvent) SetSignal(s int) *TaskEvent {
	e.Signal = s
	e.Details["signal"] = fmt.Sprintf("%d", s)
	return e
}

func (e *TaskEvent) SetSignalText(s string) *TaskEvent {
	e.Details["signal"] = s
	return e
}

func (e *TaskEvent) SetExitMessage(err error) *TaskEvent {
	if err != nil {
		e.Message = err.Error()
		e.Details["exit_message"] = err.Error()
	}
	return e
}

func (e *TaskEvent) SetKillError(err error) *TaskEvent {
	if err != nil {
		e.KillError = err.Error()
		e.Details["kill_error"] = err.Error()
	}
	return e
}

func (e *TaskEvent) SetKillReason(r string) *TaskEvent {
	e.KillReason = r
	e.Details["kill_reason"] = r
	return e
}

func (e *TaskEvent) SetRestartDelay(delay time.Duration) *TaskEvent {
	e.StartDelay = int64(delay)
	e.Details["start_delay"] = fmt.Sprintf("%d", delay)
	return e
}

func (e *TaskEvent) SetRestartReason(reason string) *TaskEvent {
	e.RestartReason = reason
	e.Details["restart_reason"] = reason
	return e
}

func (e *TaskEvent) SetTaskSignalReason(r string) *TaskEvent {
	e.TaskSignalReason = r
	e.Details["task_signal_reason"] = r
	return e
}

func (e *TaskEvent) SetTaskSignal(s os.Signal) *TaskEvent {
	e.TaskSignal = s.String()
	e.Details["task_signal"] = s.String()
	return e
}

func (e *TaskEvent) SetDownloadError(err error) *TaskEvent {
	if err != nil {
		e.DownloadError = err.Error()
		e.Details["download_error"] = err.Error()
	}
	return e
}

func (e *TaskEvent) SetValidationError(err error) *TaskEvent {
	if err != nil {
		e.ValidationError = err.Error()
		e.Details["validation_error"] = err.Error()
	}
	return e
}

func (e *TaskEvent) SetKillTimeout(timeout time.Duration) *TaskEvent {
	e.KillTimeout = timeout
	e.Details["kill_timeout"] = timeout.String()
	return e
}

func (e *TaskEvent) SetDiskLimit(limit int64) *TaskEvent {
	e.DiskLimit = limit
	e.Details["disk_limit"] = fmt.Sprintf("%d", limit)
	return e
}

func (e *TaskEvent) SetFailedSibling(sibling string) *TaskEvent {
	e.FailedSibling = sibling
	e.Details["failed_sibling"] = sibling
	return e
}

func (e *TaskEvent) SetVaultRenewalError(err error) *TaskEvent {
	if err != nil {
		e.VaultError = err.Error()
		e.Details["vault_renewal_error"] = err.Error()
	}
	return e
}

func (e *TaskEvent) SetDriverMessage(m string) *TaskEvent {
	e.DriverMessage = m
	e.Details["driver_message"] = m
	return e
}

func (e *TaskEvent) SetOOMKilled(oom bool) *TaskEvent {
	e.Details["oom_killed"] = strconv.FormatBool(oom)
	return e
}

// TaskArtifact is an artifact to download before running the task.
type TaskArtifact struct {
	// GetterSource is the source to download an artifact using go-getter
	GetterSource string

	// GetterOptions are options to use when downloading the artifact using
	// go-getter.
	GetterOptions map[string]string

	// GetterHeaders are headers to use when downloading the artifact using
	// go-getter.
	GetterHeaders map[string]string

	// GetterMode is the go-getter.ClientMode for fetching resources.
	// Defaults to "any" but can be set to "file" or "dir".
	GetterMode string

	// RelativeDest is the download destination given relative to the task's
	// directory.
	RelativeDest string
}

func (ta *TaskArtifact) Copy() *TaskArtifact {
	if ta == nil {
		return nil
	}
	return &TaskArtifact{
		GetterSource:  ta.GetterSource,
		GetterOptions: helper.CopyMapStringString(ta.GetterOptions),
		GetterHeaders: helper.CopyMapStringString(ta.GetterHeaders),
		GetterMode:    ta.GetterMode,
		RelativeDest:  ta.RelativeDest,
	}
}

func (ta *TaskArtifact) GoString() string {
	return fmt.Sprintf("%+v", ta)
}

// hashStringMap appends a deterministic hash of m onto h.
func hashStringMap(h hash.Hash, m map[string]string) {
	keys := make([]string, 0, len(m))
	for k := range m {
		keys = append(keys, k)
	}
	sort.Strings(keys)
	for _, k := range keys {
		_, _ = h.Write([]byte(k))
		_, _ = h.Write([]byte(m[k]))
	}
}

// Hash creates a unique identifier for a TaskArtifact as the same GetterSource
// may be specified multiple times with different destinations.
func (ta *TaskArtifact) Hash() string {
	h, err := blake2b.New256(nil)
	if err != nil {
		panic(err)
	}

	_, _ = h.Write([]byte(ta.GetterSource))

	hashStringMap(h, ta.GetterOptions)
	hashStringMap(h, ta.GetterHeaders)

	_, _ = h.Write([]byte(ta.GetterMode))
	_, _ = h.Write([]byte(ta.RelativeDest))
	return base64.RawStdEncoding.EncodeToString(h.Sum(nil))
}

// PathEscapesAllocDir returns if the given path escapes the allocation
// directory.
//
// The prefix is to joined to the path (e.g. "task/local"), and this function
// checks if path escapes the alloc dir, NOT the prefix directory within the alloc dir.
// With prefix="task/local", it will return false for "../secret", but
// true for "../../../../../../root" path; only the latter escapes the alloc dir
func PathEscapesAllocDir(prefix, path string) (bool, error) {
	// Verify the destination doesn't escape the tasks directory
	alloc, err := filepath.Abs(filepath.Join("/", "alloc-dir/", "alloc-id/"))
	if err != nil {
		return false, err
	}
	abs, err := filepath.Abs(filepath.Join(alloc, prefix, path))
	if err != nil {
		return false, err
	}
	rel, err := filepath.Rel(alloc, abs)
	if err != nil {
		return false, err
	}

	return strings.HasPrefix(rel, ".."), nil
}

func (ta *TaskArtifact) Validate() error {
	// Verify the source
	var mErr multierror.Error
	if ta.GetterSource == "" {
		mErr.Errors = append(mErr.Errors, fmt.Errorf("source must be specified"))
	}

	switch ta.GetterMode {
	case "":
		// Default to any
		ta.GetterMode = GetterModeAny
	case GetterModeAny, GetterModeFile, GetterModeDir:
		// Ok
	default:
		mErr.Errors = append(mErr.Errors, fmt.Errorf("invalid artifact mode %q; must be one of: %s, %s, %s",
			ta.GetterMode, GetterModeAny, GetterModeFile, GetterModeDir))
	}

	escaped, err := PathEscapesAllocDir("task", ta.RelativeDest)
	if err != nil {
		mErr.Errors = append(mErr.Errors, fmt.Errorf("invalid destination path: %v", err))
	} else if escaped {
		mErr.Errors = append(mErr.Errors, fmt.Errorf("destination escapes allocation directory"))
	}

	if err := ta.validateChecksum(); err != nil {
		mErr.Errors = append(mErr.Errors, err)
	}

	return mErr.ErrorOrNil()
}

func (ta *TaskArtifact) validateChecksum() error {
	check, ok := ta.GetterOptions["checksum"]
	if !ok {
		return nil
	}

	// Job struct validation occurs before interpolation resolution can be effective.
	// Skip checking if checksum contain variable reference, and artifacts fetching will
	// eventually fail, if checksum is indeed invalid.
	if args.ContainsEnv(check) {
		return nil
	}

	check = strings.TrimSpace(check)
	if check == "" {
		return fmt.Errorf("checksum value cannot be empty")
	}

	parts := strings.Split(check, ":")
	if l := len(parts); l != 2 {
		return fmt.Errorf(`checksum must be given as "type:value"; got %q`, check)
	}

	checksumVal := parts[1]
	checksumBytes, err := hex.DecodeString(checksumVal)
	if err != nil {
		return fmt.Errorf("invalid checksum: %v", err)
	}

	checksumType := parts[0]
	expectedLength := 0
	switch checksumType {
	case "md5":
		expectedLength = md5.Size
	case "sha1":
		expectedLength = sha1.Size
	case "sha256":
		expectedLength = sha256.Size
	case "sha512":
		expectedLength = sha512.Size
	default:
		return fmt.Errorf("unsupported checksum type: %s", checksumType)
	}

	if len(checksumBytes) != expectedLength {
		return fmt.Errorf("invalid %s checksum: %v", checksumType, checksumVal)
	}

	return nil
}

const (
	ConstraintDistinctProperty  = "distinct_property"
	ConstraintDistinctHosts     = "distinct_hosts"
	ConstraintRegex             = "regexp"
	ConstraintVersion           = "version"
	ConstraintSemver            = "semver"
	ConstraintSetContains       = "set_contains"
	ConstraintSetContainsAll    = "set_contains_all"
	ConstraintSetContainsAny    = "set_contains_any"
	ConstraintAttributeIsSet    = "is_set"
	ConstraintAttributeIsNotSet = "is_not_set"
)

// Constraints are used to restrict placement options.
type Constraint struct {
	LTarget string // Left-hand target
	RTarget string // Right-hand target
	Operand string // Constraint operand (<=, <, =, !=, >, >=), contains, near
	str     string // Memoized string
}

// Equal checks if two constraints are equal
func (c *Constraint) Equals(o *Constraint) bool {
	return c == o ||
		c.LTarget == o.LTarget &&
			c.RTarget == o.RTarget &&
			c.Operand == o.Operand
}

func (c *Constraint) Equal(o *Constraint) bool {
	return c.Equals(o)
}

func (c *Constraint) Copy() *Constraint {
	if c == nil {
		return nil
	}
	nc := new(Constraint)
	*nc = *c
	return nc
}

func (c *Constraint) String() string {
	if c.str != "" {
		return c.str
	}
	c.str = fmt.Sprintf("%s %s %s", c.LTarget, c.Operand, c.RTarget)
	return c.str
}

func (c *Constraint) Validate() error {
	var mErr multierror.Error
	if c.Operand == "" {
		mErr.Errors = append(mErr.Errors, errors.New("Missing constraint operand"))
	}

	// requireLtarget specifies whether the constraint requires an LTarget to be
	// provided.
	requireLtarget := true

	// Perform additional validation based on operand
	switch c.Operand {
	case ConstraintDistinctHosts:
		requireLtarget = false
	case ConstraintSetContainsAll, ConstraintSetContainsAny, ConstraintSetContains:
		if c.RTarget == "" {
			mErr.Errors = append(mErr.Errors, fmt.Errorf("Set contains constraint requires an RTarget"))
		}
	case ConstraintRegex:
		if _, err := regexp.Compile(c.RTarget); err != nil {
			mErr.Errors = append(mErr.Errors, fmt.Errorf("Regular expression failed to compile: %v", err))
		}
	case ConstraintVersion:
		if _, err := version.NewConstraint(c.RTarget); err != nil {
			mErr.Errors = append(mErr.Errors, fmt.Errorf("Version constraint is invalid: %v", err))
		}
	case ConstraintSemver:
		if _, err := semver.NewConstraint(c.RTarget); err != nil {
			mErr.Errors = append(mErr.Errors, fmt.Errorf("Semver constraint is invalid: %v", err))
		}
	case ConstraintDistinctProperty:
		// If a count is set, make sure it is convertible to a uint64
		if c.RTarget != "" {
			count, err := strconv.ParseUint(c.RTarget, 10, 64)
			if err != nil {
				mErr.Errors = append(mErr.Errors, fmt.Errorf("Failed to convert RTarget %q to uint64: %v", c.RTarget, err))
			} else if count < 1 {
				mErr.Errors = append(mErr.Errors, fmt.Errorf("Distinct Property must have an allowed count of 1 or greater: %d < 1", count))
			}
		}
	case ConstraintAttributeIsSet, ConstraintAttributeIsNotSet:
		if c.RTarget != "" {
			mErr.Errors = append(mErr.Errors, fmt.Errorf("Operator %q does not support an RTarget", c.Operand))
		}
	case "=", "==", "is", "!=", "not", "<", "<=", ">", ">=":
		if c.RTarget == "" {
			mErr.Errors = append(mErr.Errors, fmt.Errorf("Operator %q requires an RTarget", c.Operand))
		}
	default:
		mErr.Errors = append(mErr.Errors, fmt.Errorf("Unknown constraint type %q", c.Operand))
	}

	// Ensure we have an LTarget for the constraints that need one
	if requireLtarget && c.LTarget == "" {
		mErr.Errors = append(mErr.Errors, fmt.Errorf("No LTarget provided but is required by constraint"))
	}

	return mErr.ErrorOrNil()
}

type Constraints []*Constraint

// Equals compares Constraints as a set
func (xs *Constraints) Equals(ys *Constraints) bool {
	if xs == ys {
		return true
	}
	if xs == nil || ys == nil {
		return false
	}
	if len(*xs) != len(*ys) {
		return false
	}
SETEQUALS:
	for _, x := range *xs {
		for _, y := range *ys {
			if x.Equals(y) {
				continue SETEQUALS
			}
		}
		return false
	}
	return true
}

// Affinity is used to score placement options based on a weight
type Affinity struct {
	LTarget string // Left-hand target
	RTarget string // Right-hand target
	Operand string // Affinity operand (<=, <, =, !=, >, >=), set_contains_all, set_contains_any
	Weight  int8   // Weight applied to nodes that match the affinity. Can be negative
	str     string // Memoized string
}

// Equal checks if two affinities are equal
func (a *Affinity) Equals(o *Affinity) bool {
	return a == o ||
		a.LTarget == o.LTarget &&
			a.RTarget == o.RTarget &&
			a.Operand == o.Operand &&
			a.Weight == o.Weight
}

func (a *Affinity) Equal(o *Affinity) bool {
	return a.Equals(o)
}

func (a *Affinity) Copy() *Affinity {
	if a == nil {
		return nil
	}
	na := new(Affinity)
	*na = *a
	return na
}

func (a *Affinity) String() string {
	if a.str != "" {
		return a.str
	}
	a.str = fmt.Sprintf("%s %s %s %v", a.LTarget, a.Operand, a.RTarget, a.Weight)
	return a.str
}

func (a *Affinity) Validate() error {
	var mErr multierror.Error
	if a.Operand == "" {
		mErr.Errors = append(mErr.Errors, errors.New("Missing affinity operand"))
	}

	// Perform additional validation based on operand
	switch a.Operand {
	case ConstraintSetContainsAll, ConstraintSetContainsAny, ConstraintSetContains:
		if a.RTarget == "" {
			mErr.Errors = append(mErr.Errors, fmt.Errorf("Set contains operators require an RTarget"))
		}
	case ConstraintRegex:
		if _, err := regexp.Compile(a.RTarget); err != nil {
			mErr.Errors = append(mErr.Errors, fmt.Errorf("Regular expression failed to compile: %v", err))
		}
	case ConstraintVersion:
		if _, err := version.NewConstraint(a.RTarget); err != nil {
			mErr.Errors = append(mErr.Errors, fmt.Errorf("Version affinity is invalid: %v", err))
		}
	case ConstraintSemver:
		if _, err := semver.NewConstraint(a.RTarget); err != nil {
			mErr.Errors = append(mErr.Errors, fmt.Errorf("Semver affinity is invalid: %v", err))
		}
	case "=", "==", "is", "!=", "not", "<", "<=", ">", ">=":
		if a.RTarget == "" {
			mErr.Errors = append(mErr.Errors, fmt.Errorf("Operator %q requires an RTarget", a.Operand))
		}
	default:
		mErr.Errors = append(mErr.Errors, fmt.Errorf("Unknown affinity operator %q", a.Operand))
	}

	// Ensure we have an LTarget
	if a.LTarget == "" {
		mErr.Errors = append(mErr.Errors, fmt.Errorf("No LTarget provided but is required"))
	}

	// Ensure that weight is between -100 and 100, and not zero
	if a.Weight == 0 {
		mErr.Errors = append(mErr.Errors, fmt.Errorf("Affinity weight cannot be zero"))
	}

	if a.Weight > 100 || a.Weight < -100 {
		mErr.Errors = append(mErr.Errors, fmt.Errorf("Affinity weight must be within the range [-100,100]"))
	}

	return mErr.ErrorOrNil()
}

// Spread is used to specify desired distribution of allocations according to weight
type Spread struct {
	// Attribute is the node attribute used as the spread criteria
	Attribute string

	// Weight is the relative weight of this spread, useful when there are multiple
	// spread and affinities
	Weight int8

	// SpreadTarget is used to describe desired percentages for each attribute value
	SpreadTarget []*SpreadTarget

	// Memoized string representation
	str string
}

type Affinities []*Affinity

// Equals compares Affinities as a set
func (xs *Affinities) Equals(ys *Affinities) bool {
	if xs == ys {
		return true
	}
	if xs == nil || ys == nil {
		return false
	}
	if len(*xs) != len(*ys) {
		return false
	}
SETEQUALS:
	for _, x := range *xs {
		for _, y := range *ys {
			if x.Equals(y) {
				continue SETEQUALS
			}
		}
		return false
	}
	return true
}

func (s *Spread) Copy() *Spread {
	if s == nil {
		return nil
	}
	ns := new(Spread)
	*ns = *s

	ns.SpreadTarget = CopySliceSpreadTarget(s.SpreadTarget)
	return ns
}

func (s *Spread) String() string {
	if s.str != "" {
		return s.str
	}
	s.str = fmt.Sprintf("%s %s %v", s.Attribute, s.SpreadTarget, s.Weight)
	return s.str
}

func (s *Spread) Validate() error {
	var mErr multierror.Error
	if s.Attribute == "" {
		mErr.Errors = append(mErr.Errors, errors.New("Missing spread attribute"))
	}
	if s.Weight <= 0 || s.Weight > 100 {
		mErr.Errors = append(mErr.Errors, errors.New("Spread stanza must have a positive weight from 0 to 100"))
	}
	seen := make(map[string]struct{})
	sumPercent := uint32(0)

	for _, target := range s.SpreadTarget {
		// Make sure there are no duplicates
		_, ok := seen[target.Value]
		if !ok {
			seen[target.Value] = struct{}{}
		} else {
			mErr.Errors = append(mErr.Errors, fmt.Errorf("Spread target value %q already defined", target.Value))
		}
		if target.Percent > 100 {
			mErr.Errors = append(mErr.Errors, fmt.Errorf("Spread target percentage for value %q must be between 0 and 100", target.Value))
		}
		sumPercent += uint32(target.Percent)
	}
	if sumPercent > 100 {
		mErr.Errors = append(mErr.Errors, fmt.Errorf("Sum of spread target percentages must not be greater than 100%%; got %d%%", sumPercent))
	}
	return mErr.ErrorOrNil()
}

// SpreadTarget is used to specify desired percentages for each attribute value
type SpreadTarget struct {
	// Value is a single attribute value, like "dc1"
	Value string

	// Percent is the desired percentage of allocs
	Percent uint8

	// Memoized string representation
	str string
}

func (s *SpreadTarget) Copy() *SpreadTarget {
	if s == nil {
		return nil
	}

	ns := new(SpreadTarget)
	*ns = *s
	return ns
}

func (s *SpreadTarget) String() string {
	if s.str != "" {
		return s.str
	}
	s.str = fmt.Sprintf("%q %v%%", s.Value, s.Percent)
	return s.str
}

// EphemeralDisk is an ephemeral disk object
type EphemeralDisk struct {
	// Sticky indicates whether the allocation is sticky to a node
	Sticky bool

	// SizeMB is the size of the local disk
	SizeMB int

	// Migrate determines if Nomad client should migrate the allocation dir for
	// sticky allocations
	Migrate bool
}

// DefaultEphemeralDisk returns a EphemeralDisk with default configurations
func DefaultEphemeralDisk() *EphemeralDisk {
	return &EphemeralDisk{
		SizeMB: 300,
	}
}

// Validate validates EphemeralDisk
func (d *EphemeralDisk) Validate() error {
	if d.SizeMB < 10 {
		return fmt.Errorf("minimum DiskMB value is 10; got %d", d.SizeMB)
	}
	return nil
}

// Copy copies the EphemeralDisk struct and returns a new one
func (d *EphemeralDisk) Copy() *EphemeralDisk {
	ld := new(EphemeralDisk)
	*ld = *d
	return ld
}

var (
	// VaultUnrecoverableError matches unrecoverable errors returned by a Vault
	// server
	VaultUnrecoverableError = regexp.MustCompile(`Code:\s+40(0|3|4)`)
)

const (
	// VaultChangeModeNoop takes no action when a new token is retrieved.
	VaultChangeModeNoop = "noop"

	// VaultChangeModeSignal signals the task when a new token is retrieved.
	VaultChangeModeSignal = "signal"

	// VaultChangeModeRestart restarts the task when a new token is retrieved.
	VaultChangeModeRestart = "restart"
)

// Vault stores the set of permissions a task needs access to from Vault.
type Vault struct {
	// Policies is the set of policies that the task needs access to
	Policies []string

	// Namespace is the vault namespace that should be used.
	Namespace string

	// Env marks whether the Vault Token should be exposed as an environment
	// variable
	Env bool

	// ChangeMode is used to configure the task's behavior when the Vault
	// token changes because the original token could not be renewed in time.
	ChangeMode string

	// ChangeSignal is the signal sent to the task when a new token is
	// retrieved. This is only valid when using the signal change mode.
	ChangeSignal string
}

func DefaultVaultBlock() *Vault {
	return &Vault{
		Env:        true,
		ChangeMode: VaultChangeModeRestart,
	}
}

// Copy returns a copy of this Vault block.
func (v *Vault) Copy() *Vault {
	if v == nil {
		return nil
	}

	nv := new(Vault)
	*nv = *v
	return nv
}

func (v *Vault) Canonicalize() {
	if v.ChangeSignal != "" {
		v.ChangeSignal = strings.ToUpper(v.ChangeSignal)
	}
}

// Validate returns if the Vault block is valid.
func (v *Vault) Validate() error {
	if v == nil {
		return nil
	}

	var mErr multierror.Error
	if len(v.Policies) == 0 {
		_ = multierror.Append(&mErr, fmt.Errorf("Policy list cannot be empty"))
	}

	for _, p := range v.Policies {
		if p == "root" {
			_ = multierror.Append(&mErr, fmt.Errorf("Can not specify \"root\" policy"))
		}
	}

	switch v.ChangeMode {
	case VaultChangeModeSignal:
		if v.ChangeSignal == "" {
			_ = multierror.Append(&mErr, fmt.Errorf("Signal must be specified when using change mode %q", VaultChangeModeSignal))
		}
	case VaultChangeModeNoop, VaultChangeModeRestart:
	default:
		_ = multierror.Append(&mErr, fmt.Errorf("Unknown change mode %q", v.ChangeMode))
	}

	return mErr.ErrorOrNil()
}

const (
	// DeploymentStatuses are the various states a deployment can be be in
	DeploymentStatusRunning    = "running"
	DeploymentStatusPaused     = "paused"
	DeploymentStatusFailed     = "failed"
	DeploymentStatusSuccessful = "successful"
	DeploymentStatusCancelled  = "cancelled"
	DeploymentStatusPending    = "pending"
	DeploymentStatusBlocked    = "blocked"
	DeploymentStatusUnblocking = "unblocking"

	// TODO Statuses and Descriptions do not match 1:1 and we sometimes use the Description as a status flag

	// DeploymentStatusDescriptions are the various descriptions of the states a
	// deployment can be in.
	DeploymentStatusDescriptionRunning               = "Deployment is running"
	DeploymentStatusDescriptionRunningNeedsPromotion = "Deployment is running but requires manual promotion"
	DeploymentStatusDescriptionRunningAutoPromotion  = "Deployment is running pending automatic promotion"
	DeploymentStatusDescriptionPaused                = "Deployment is paused"
	DeploymentStatusDescriptionSuccessful            = "Deployment completed successfully"
	DeploymentStatusDescriptionStoppedJob            = "Cancelled because job is stopped"
	DeploymentStatusDescriptionNewerJob              = "Cancelled due to newer version of job"
	DeploymentStatusDescriptionFailedAllocations     = "Failed due to unhealthy allocations"
	DeploymentStatusDescriptionProgressDeadline      = "Failed due to progress deadline"
	DeploymentStatusDescriptionFailedByUser          = "Deployment marked as failed"

	// used only in multiregion deployments
	DeploymentStatusDescriptionFailedByPeer   = "Failed because of an error in peer region"
	DeploymentStatusDescriptionBlocked        = "Deployment is complete but waiting for peer region"
	DeploymentStatusDescriptionUnblocking     = "Deployment is unblocking remaining regions"
	DeploymentStatusDescriptionPendingForPeer = "Deployment is pending, waiting for peer region"
)

// DeploymentStatusDescriptionRollback is used to get the status description of
// a deployment when rolling back to an older job.
func DeploymentStatusDescriptionRollback(baseDescription string, jobVersion uint64) string {
	return fmt.Sprintf("%s - rolling back to job version %d", baseDescription, jobVersion)
}

// DeploymentStatusDescriptionRollbackNoop is used to get the status description of
// a deployment when rolling back is not possible because it has the same specification
func DeploymentStatusDescriptionRollbackNoop(baseDescription string, jobVersion uint64) string {
	return fmt.Sprintf("%s - not rolling back to stable job version %d as current job has same specification", baseDescription, jobVersion)
}

// DeploymentStatusDescriptionNoRollbackTarget is used to get the status description of
// a deployment when there is no target to rollback to but autorevert is desired.
func DeploymentStatusDescriptionNoRollbackTarget(baseDescription string) string {
	return fmt.Sprintf("%s - no stable job version to auto revert to", baseDescription)
}

// Deployment is the object that represents a job deployment which is used to
// transition a job between versions.
type Deployment struct {
	// ID is a generated UUID for the deployment
	ID string

	// Namespace is the namespace the deployment is created in
	Namespace string

	// JobID is the job the deployment is created for
	JobID string

	// JobVersion is the version of the job at which the deployment is tracking
	JobVersion uint64

	// JobModifyIndex is the ModifyIndex of the job which the deployment is
	// tracking.
	JobModifyIndex uint64

	// JobSpecModifyIndex is the JobModifyIndex of the job which the
	// deployment is tracking.
	JobSpecModifyIndex uint64

	// JobCreateIndex is the create index of the job which the deployment is
	// tracking. It is needed so that if the job gets stopped and reran we can
	// present the correct list of deployments for the job and not old ones.
	JobCreateIndex uint64

	// Multiregion specifies if deployment is part of multiregion deployment
	IsMultiregion bool

	// TaskGroups is the set of task groups effected by the deployment and their
	// current deployment status.
	TaskGroups map[string]*DeploymentState

	// The status of the deployment
	Status string

	// StatusDescription allows a human readable description of the deployment
	// status.
	StatusDescription string

	CreateIndex uint64
	ModifyIndex uint64
}

// NewDeployment creates a new deployment given the job.
func NewDeployment(job *Job) *Deployment {
	return &Deployment{
		ID:                 uuid.Generate(),
		Namespace:          job.Namespace,
		JobID:              job.ID,
		JobVersion:         job.Version,
		JobModifyIndex:     job.ModifyIndex,
		JobSpecModifyIndex: job.JobModifyIndex,
		JobCreateIndex:     job.CreateIndex,
		IsMultiregion:      job.IsMultiregion(),
		Status:             DeploymentStatusRunning,
		StatusDescription:  DeploymentStatusDescriptionRunning,
		TaskGroups:         make(map[string]*DeploymentState, len(job.TaskGroups)),
	}
}

func (d *Deployment) Copy() *Deployment {
	if d == nil {
		return nil
	}

	c := &Deployment{}
	*c = *d

	c.TaskGroups = nil
	if l := len(d.TaskGroups); d.TaskGroups != nil {
		c.TaskGroups = make(map[string]*DeploymentState, l)
		for tg, s := range d.TaskGroups {
			c.TaskGroups[tg] = s.Copy()
		}
	}

	return c
}

// Active returns whether the deployment is active or terminal.
func (d *Deployment) Active() bool {
	switch d.Status {
	case DeploymentStatusRunning, DeploymentStatusPaused, DeploymentStatusBlocked, DeploymentStatusUnblocking, DeploymentStatusPending:
		return true
	default:
		return false
	}
}

// GetID is a helper for getting the ID when the object may be nil
func (d *Deployment) GetID() string {
	if d == nil {
		return ""
	}
	return d.ID
}

// HasPlacedCanaries returns whether the deployment has placed canaries
func (d *Deployment) HasPlacedCanaries() bool {
	if d == nil || len(d.TaskGroups) == 0 {
		return false
	}
	for _, group := range d.TaskGroups {
		if len(group.PlacedCanaries) != 0 {
			return true
		}
	}
	return false
}

// RequiresPromotion returns whether the deployment requires promotion to
// continue
func (d *Deployment) RequiresPromotion() bool {
	if d == nil || len(d.TaskGroups) == 0 || d.Status != DeploymentStatusRunning {
		return false
	}
	for _, group := range d.TaskGroups {
		if group.DesiredCanaries > 0 && !group.Promoted {
			return true
		}
	}
	return false
}

// HasAutoPromote determines if all taskgroups are marked auto_promote
func (d *Deployment) HasAutoPromote() bool {
	if d == nil || len(d.TaskGroups) == 0 || d.Status != DeploymentStatusRunning {
		return false
	}
	for _, group := range d.TaskGroups {
		if !group.AutoPromote {
			return false
		}
	}
	return true
}

func (d *Deployment) GoString() string {
	base := fmt.Sprintf("Deployment ID %q for job %q has status %q (%v):", d.ID, d.JobID, d.Status, d.StatusDescription)
	for group, state := range d.TaskGroups {
		base += fmt.Sprintf("\nTask Group %q has state:\n%#v", group, state)
	}
	return base
}

// DeploymentState tracks the state of a deployment for a given task group.
type DeploymentState struct {
	// AutoRevert marks whether the task group has indicated the job should be
	// reverted on failure
	AutoRevert bool

	// AutoPromote marks promotion triggered automatically by healthy canaries
	// copied from TaskGroup UpdateStrategy in scheduler.reconcile
	AutoPromote bool

	// ProgressDeadline is the deadline by which an allocation must transition
	// to healthy before the deployment is considered failed. This value is set
	// by the jobspec `update.progress_deadline` field.
	ProgressDeadline time.Duration

	// RequireProgressBy is the time by which an allocation must transition to
	// healthy before the deployment is considered failed. This value is reset
	// to "now" + ProgressDeadline when an allocation updates the deployment.
	RequireProgressBy time.Time

	// Promoted marks whether the canaries have been promoted
	Promoted bool

	// PlacedCanaries is the set of placed canary allocations
	PlacedCanaries []string

	// DesiredCanaries is the number of canaries that should be created.
	DesiredCanaries int

	// DesiredTotal is the total number of allocations that should be created as
	// part of the deployment.
	DesiredTotal int

	// PlacedAllocs is the number of allocations that have been placed
	PlacedAllocs int

	// HealthyAllocs is the number of allocations that have been marked healthy.
	HealthyAllocs int

	// UnhealthyAllocs are allocations that have been marked as unhealthy.
	UnhealthyAllocs int
}

func (d *DeploymentState) GoString() string {
	base := fmt.Sprintf("\tDesired Total: %d", d.DesiredTotal)
	base += fmt.Sprintf("\n\tDesired Canaries: %d", d.DesiredCanaries)
	base += fmt.Sprintf("\n\tPlaced Canaries: %#v", d.PlacedCanaries)
	base += fmt.Sprintf("\n\tPromoted: %v", d.Promoted)
	base += fmt.Sprintf("\n\tPlaced: %d", d.PlacedAllocs)
	base += fmt.Sprintf("\n\tHealthy: %d", d.HealthyAllocs)
	base += fmt.Sprintf("\n\tUnhealthy: %d", d.UnhealthyAllocs)
	base += fmt.Sprintf("\n\tAutoRevert: %v", d.AutoRevert)
	base += fmt.Sprintf("\n\tAutoPromote: %v", d.AutoPromote)
	return base
}

func (d *DeploymentState) Copy() *DeploymentState {
	c := &DeploymentState{}
	*c = *d
	c.PlacedCanaries = helper.CopySliceString(d.PlacedCanaries)
	return c
}

// DeploymentStatusUpdate is used to update the status of a given deployment
type DeploymentStatusUpdate struct {
	// DeploymentID is the ID of the deployment to update
	DeploymentID string

	// Status is the new status of the deployment.
	Status string

	// StatusDescription is the new status description of the deployment.
	StatusDescription string
}

// RescheduleTracker encapsulates previous reschedule events
type RescheduleTracker struct {
	Events []*RescheduleEvent
}

func (rt *RescheduleTracker) Copy() *RescheduleTracker {
	if rt == nil {
		return nil
	}
	nt := &RescheduleTracker{}
	*nt = *rt
	rescheduleEvents := make([]*RescheduleEvent, 0, len(rt.Events))
	for _, tracker := range rt.Events {
		rescheduleEvents = append(rescheduleEvents, tracker.Copy())
	}
	nt.Events = rescheduleEvents
	return nt
}

// RescheduleEvent is used to keep track of previous attempts at rescheduling an allocation
type RescheduleEvent struct {
	// RescheduleTime is the timestamp of a reschedule attempt
	RescheduleTime int64

	// PrevAllocID is the ID of the previous allocation being restarted
	PrevAllocID string

	// PrevNodeID is the node ID of the previous allocation
	PrevNodeID string

	// Delay is the reschedule delay associated with the attempt
	Delay time.Duration
}

func NewRescheduleEvent(rescheduleTime int64, prevAllocID string, prevNodeID string, delay time.Duration) *RescheduleEvent {
	return &RescheduleEvent{RescheduleTime: rescheduleTime,
		PrevAllocID: prevAllocID,
		PrevNodeID:  prevNodeID,
		Delay:       delay}
}

func (re *RescheduleEvent) Copy() *RescheduleEvent {
	if re == nil {
		return nil
	}
	copy := new(RescheduleEvent)
	*copy = *re
	return copy
}

// DesiredTransition is used to mark an allocation as having a desired state
// transition. This information can be used by the scheduler to make the
// correct decision.
type DesiredTransition struct {
	// Migrate is used to indicate that this allocation should be stopped and
	// migrated to another node.
	Migrate *bool

	// Reschedule is used to indicate that this allocation is eligible to be
	// rescheduled. Most allocations are automatically eligible for
	// rescheduling, so this field is only required when an allocation is not
	// automatically eligible. An example is an allocation that is part of a
	// deployment.
	Reschedule *bool

	// ForceReschedule is used to indicate that this allocation must be rescheduled.
	// This field is only used when operators want to force a placement even if
	// a failed allocation is not eligible to be rescheduled
	ForceReschedule *bool
}

// Merge merges the two desired transitions, preferring the values from the
// passed in object.
func (d *DesiredTransition) Merge(o *DesiredTransition) {
	if o.Migrate != nil {
		d.Migrate = o.Migrate
	}

	if o.Reschedule != nil {
		d.Reschedule = o.Reschedule
	}

	if o.ForceReschedule != nil {
		d.ForceReschedule = o.ForceReschedule
	}
}

// ShouldMigrate returns whether the transition object dictates a migration.
func (d *DesiredTransition) ShouldMigrate() bool {
	return d.Migrate != nil && *d.Migrate
}

// ShouldReschedule returns whether the transition object dictates a
// rescheduling.
func (d *DesiredTransition) ShouldReschedule() bool {
	return d.Reschedule != nil && *d.Reschedule
}

// ShouldForceReschedule returns whether the transition object dictates a
// forced rescheduling.
func (d *DesiredTransition) ShouldForceReschedule() bool {
	if d == nil {
		return false
	}
	return d.ForceReschedule != nil && *d.ForceReschedule
}

const (
	AllocDesiredStatusRun   = "run"   // Allocation should run
	AllocDesiredStatusStop  = "stop"  // Allocation should stop
	AllocDesiredStatusEvict = "evict" // Allocation should stop, and was evicted
)

const (
	AllocClientStatusPending  = "pending"
	AllocClientStatusRunning  = "running"
	AllocClientStatusComplete = "complete"
	AllocClientStatusFailed   = "failed"
	AllocClientStatusLost     = "lost"
)

// Allocation is used to allocate the placement of a task group to a node.
type Allocation struct {
	// msgpack omit empty fields during serialization
	_struct bool `codec:",omitempty"` // nolint: structcheck

	// ID of the allocation (UUID)
	ID string

	// Namespace is the namespace the allocation is created in
	Namespace string

	// ID of the evaluation that generated this allocation
	EvalID string

	// Name is a logical name of the allocation.
	Name string

	// NodeID is the node this is being placed on
	NodeID string

	// NodeName is the name of the node this is being placed on.
	NodeName string

	// Job is the parent job of the task group being allocated.
	// This is copied at allocation time to avoid issues if the job
	// definition is updated.
	JobID string
	Job   *Job

	// TaskGroup is the name of the task group that should be run
	TaskGroup string

	// COMPAT(0.11): Remove in 0.11
	// Resources is the total set of resources allocated as part
	// of this allocation of the task group. Dynamic ports will be set by
	// the scheduler.
	Resources *Resources

	// SharedResources are the resources that are shared by all the tasks in an
	// allocation
	// Deprecated: use AllocatedResources.Shared instead.
	// Keep field to allow us to handle upgrade paths from old versions
	SharedResources *Resources

	// TaskResources is the set of resources allocated to each
	// task. These should sum to the total Resources. Dynamic ports will be
	// set by the scheduler.
	// Deprecated: use AllocatedResources.Tasks instead.
	// Keep field to allow us to handle upgrade paths from old versions
	TaskResources map[string]*Resources

	// AllocatedResources is the total resources allocated for the task group.
	AllocatedResources *AllocatedResources

	// Metrics associated with this allocation
	Metrics *AllocMetric

	// Desired Status of the allocation on the client
	DesiredStatus string

	// DesiredStatusDescription is meant to provide more human useful information
	DesiredDescription string

	// DesiredTransition is used to indicate that a state transition
	// is desired for a given reason.
	DesiredTransition DesiredTransition

	// Status of the allocation on the client
	ClientStatus string

	// ClientStatusDescription is meant to provide more human useful information
	ClientDescription string

	// TaskStates stores the state of each task,
	TaskStates map[string]*TaskState

	// AllocStates track meta data associated with changes to the state of the whole allocation, like becoming lost
	AllocStates []*AllocState

	// PreviousAllocation is the allocation that this allocation is replacing
	PreviousAllocation string

	// NextAllocation is the allocation that this allocation is being replaced by
	NextAllocation string

	// DeploymentID identifies an allocation as being created from a
	// particular deployment
	DeploymentID string

	// DeploymentStatus captures the status of the allocation as part of the
	// given deployment
	DeploymentStatus *AllocDeploymentStatus

	// RescheduleTrackers captures details of previous reschedule attempts of the allocation
	RescheduleTracker *RescheduleTracker

	// NetworkStatus captures networking details of an allocation known at runtime
	NetworkStatus *AllocNetworkStatus

	// FollowupEvalID captures a follow up evaluation created to handle a failed allocation
	// that can be rescheduled in the future
	FollowupEvalID string

	// PreemptedAllocations captures IDs of any allocations that were preempted
	// in order to place this allocation
	PreemptedAllocations []string

	// PreemptedByAllocation tracks the alloc ID of the allocation that caused this allocation
	// to stop running because it got preempted
	PreemptedByAllocation string

	// Raft Indexes
	CreateIndex uint64
	ModifyIndex uint64

	// AllocModifyIndex is not updated when the client updates allocations. This
	// lets the client pull only the allocs updated by the server.
	AllocModifyIndex uint64

	// CreateTime is the time the allocation has finished scheduling and been
	// verified by the plan applier.
	CreateTime int64

	// ModifyTime is the time the allocation was last updated.
	ModifyTime int64
}

// Index returns the index of the allocation. If the allocation is from a task
// group with count greater than 1, there will be multiple allocations for it.
func (a *Allocation) Index() uint {
	l := len(a.Name)
	prefix := len(a.JobID) + len(a.TaskGroup) + 2
	if l <= 3 || l <= prefix {
		return uint(0)
	}

	strNum := a.Name[prefix : len(a.Name)-1]
	num, _ := strconv.Atoi(strNum)
	return uint(num)
}

// Copy provides a copy of the allocation and deep copies the job
func (a *Allocation) Copy() *Allocation {
	return a.copyImpl(true)
}

// CopySkipJob provides a copy of the allocation but doesn't deep copy the job
func (a *Allocation) CopySkipJob() *Allocation {
	return a.copyImpl(false)
}

// Canonicalize Allocation to ensure fields are initialized to the expectations
// of this version of Nomad. Should be called when restoring persisted
// Allocations or receiving Allocations from Nomad agents potentially on an
// older version of Nomad.
func (a *Allocation) Canonicalize() {
	if a.AllocatedResources == nil && a.TaskResources != nil {
		ar := AllocatedResources{}

		tasks := make(map[string]*AllocatedTaskResources, len(a.TaskResources))
		for name, tr := range a.TaskResources {
			atr := AllocatedTaskResources{}
			atr.Cpu.CpuShares = int64(tr.CPU)
			atr.Memory.MemoryMB = int64(tr.MemoryMB)
			atr.Networks = tr.Networks.Copy()

			tasks[name] = &atr
		}
		ar.Tasks = tasks

		if a.SharedResources != nil {
			ar.Shared.DiskMB = int64(a.SharedResources.DiskMB)
			ar.Shared.Networks = a.SharedResources.Networks.Copy()
		}

		a.AllocatedResources = &ar
	}

	a.Job.Canonicalize()
}

func (a *Allocation) copyImpl(job bool) *Allocation {
	if a == nil {
		return nil
	}
	na := new(Allocation)
	*na = *a

	if job {
		na.Job = na.Job.Copy()
	}

	na.AllocatedResources = na.AllocatedResources.Copy()
	na.Resources = na.Resources.Copy()
	na.SharedResources = na.SharedResources.Copy()

	if a.TaskResources != nil {
		tr := make(map[string]*Resources, len(na.TaskResources))
		for task, resource := range na.TaskResources {
			tr[task] = resource.Copy()
		}
		na.TaskResources = tr
	}

	na.Metrics = na.Metrics.Copy()
	na.DeploymentStatus = na.DeploymentStatus.Copy()

	if a.TaskStates != nil {
		ts := make(map[string]*TaskState, len(na.TaskStates))
		for task, state := range na.TaskStates {
			ts[task] = state.Copy()
		}
		na.TaskStates = ts
	}

	na.RescheduleTracker = a.RescheduleTracker.Copy()
	na.PreemptedAllocations = helper.CopySliceString(a.PreemptedAllocations)
	return na
}

// TerminalStatus returns if the desired or actual status is terminal and
// will no longer transition.
func (a *Allocation) TerminalStatus() bool {
	// First check the desired state and if that isn't terminal, check client
	// state.
	return a.ServerTerminalStatus() || a.ClientTerminalStatus()
}

// ServerTerminalStatus returns true if the desired state of the allocation is terminal
func (a *Allocation) ServerTerminalStatus() bool {
	switch a.DesiredStatus {
	case AllocDesiredStatusStop, AllocDesiredStatusEvict:
		return true
	default:
		return false
	}
}

// ClientTerminalStatus returns if the client status is terminal and will no longer transition
func (a *Allocation) ClientTerminalStatus() bool {
	switch a.ClientStatus {
	case AllocClientStatusComplete, AllocClientStatusFailed, AllocClientStatusLost:
		return true
	default:
		return false
	}
}

// ShouldReschedule returns if the allocation is eligible to be rescheduled according
// to its status and ReschedulePolicy given its failure time
func (a *Allocation) ShouldReschedule(reschedulePolicy *ReschedulePolicy, failTime time.Time) bool {
	// First check the desired state
	switch a.DesiredStatus {
	case AllocDesiredStatusStop, AllocDesiredStatusEvict:
		return false
	default:
	}
	switch a.ClientStatus {
	case AllocClientStatusFailed:
		return a.RescheduleEligible(reschedulePolicy, failTime)
	default:
		return false
	}
}

// RescheduleEligible returns if the allocation is eligible to be rescheduled according
// to its ReschedulePolicy and the current state of its reschedule trackers
func (a *Allocation) RescheduleEligible(reschedulePolicy *ReschedulePolicy, failTime time.Time) bool {
	if reschedulePolicy == nil {
		return false
	}
	attempts := reschedulePolicy.Attempts
	interval := reschedulePolicy.Interval
	enabled := attempts > 0 || reschedulePolicy.Unlimited
	if !enabled {
		return false
	}
	if reschedulePolicy.Unlimited {
		return true
	}
	// Early return true if there are no attempts yet and the number of allowed attempts is > 0
	if (a.RescheduleTracker == nil || len(a.RescheduleTracker.Events) == 0) && attempts > 0 {
		return true
	}
	attempted := 0
	for j := len(a.RescheduleTracker.Events) - 1; j >= 0; j-- {
		lastAttempt := a.RescheduleTracker.Events[j].RescheduleTime
		timeDiff := failTime.UTC().UnixNano() - lastAttempt
		if timeDiff < interval.Nanoseconds() {
			attempted += 1
		}
	}
	return attempted < attempts
}

// LastEventTime is the time of the last task event in the allocation.
// It is used to determine allocation failure time. If the FinishedAt field
// is not set, the alloc's modify time is used
func (a *Allocation) LastEventTime() time.Time {
	var lastEventTime time.Time
	if a.TaskStates != nil {
		for _, s := range a.TaskStates {
			if lastEventTime.IsZero() || s.FinishedAt.After(lastEventTime) {
				lastEventTime = s.FinishedAt
			}
		}
	}

	if lastEventTime.IsZero() {
		return time.Unix(0, a.ModifyTime).UTC()
	}
	return lastEventTime
}

// ReschedulePolicy returns the reschedule policy based on the task group
func (a *Allocation) ReschedulePolicy() *ReschedulePolicy {
	tg := a.Job.LookupTaskGroup(a.TaskGroup)
	if tg == nil {
		return nil
	}
	return tg.ReschedulePolicy
}

// MigrateStrategy returns the migrate strategy based on the task group
func (a *Allocation) MigrateStrategy() *MigrateStrategy {
	tg := a.Job.LookupTaskGroup(a.TaskGroup)
	if tg == nil {
		return nil
	}
	return tg.Migrate
}

// NextRescheduleTime returns a time on or after which the allocation is eligible to be rescheduled,
// and whether the next reschedule time is within policy's interval if the policy doesn't allow unlimited reschedules
func (a *Allocation) NextRescheduleTime() (time.Time, bool) {
	failTime := a.LastEventTime()
	reschedulePolicy := a.ReschedulePolicy()
	if a.DesiredStatus == AllocDesiredStatusStop || a.ClientStatus != AllocClientStatusFailed || failTime.IsZero() || reschedulePolicy == nil {
		return time.Time{}, false
	}

	nextDelay := a.NextDelay()
	nextRescheduleTime := failTime.Add(nextDelay)
	rescheduleEligible := reschedulePolicy.Unlimited || (reschedulePolicy.Attempts > 0 && a.RescheduleTracker == nil)
	if reschedulePolicy.Attempts > 0 && a.RescheduleTracker != nil && a.RescheduleTracker.Events != nil {
		// Check for eligibility based on the interval if max attempts is set
		attempted := 0
		for j := len(a.RescheduleTracker.Events) - 1; j >= 0; j-- {
			lastAttempt := a.RescheduleTracker.Events[j].RescheduleTime
			timeDiff := failTime.UTC().UnixNano() - lastAttempt
			if timeDiff < reschedulePolicy.Interval.Nanoseconds() {
				attempted += 1
			}
		}
		rescheduleEligible = attempted < reschedulePolicy.Attempts && nextDelay < reschedulePolicy.Interval
	}
	return nextRescheduleTime, rescheduleEligible
}

// ShouldClientStop tests an alloc for StopAfterClientDisconnect configuration
func (a *Allocation) ShouldClientStop() bool {
	tg := a.Job.LookupTaskGroup(a.TaskGroup)
	if tg == nil ||
		tg.StopAfterClientDisconnect == nil ||
		*tg.StopAfterClientDisconnect == 0*time.Nanosecond {
		return false
	}
	return true
}

// WaitClientStop uses the reschedule delay mechanism to block rescheduling until
// StopAfterClientDisconnect's block interval passes
func (a *Allocation) WaitClientStop() time.Time {
	tg := a.Job.LookupTaskGroup(a.TaskGroup)

	// An alloc can only be marked lost once, so use the first lost transition
	var t time.Time
	for _, s := range a.AllocStates {
		if s.Field == AllocStateFieldClientStatus &&
			s.Value == AllocClientStatusLost {
			t = s.Time
			break
		}
	}

	// On the first pass, the alloc hasn't been marked lost yet, and so we start
	// counting from now
	if t.IsZero() {
		t = time.Now().UTC()
	}

	// Find the max kill timeout
	kill := DefaultKillTimeout
	for _, t := range tg.Tasks {
		if t.KillTimeout > kill {
			kill = t.KillTimeout
		}
	}

	return t.Add(*tg.StopAfterClientDisconnect + kill)
}

// NextDelay returns a duration after which the allocation can be rescheduled.
// It is calculated according to the delay function and previous reschedule attempts.
func (a *Allocation) NextDelay() time.Duration {
	policy := a.ReschedulePolicy()
	// Can be nil if the task group was updated to remove its reschedule policy
	if policy == nil {
		return 0
	}
	delayDur := policy.Delay
	if a.RescheduleTracker == nil || a.RescheduleTracker.Events == nil || len(a.RescheduleTracker.Events) == 0 {
		return delayDur
	}
	events := a.RescheduleTracker.Events
	switch policy.DelayFunction {
	case "exponential":
		delayDur = a.RescheduleTracker.Events[len(a.RescheduleTracker.Events)-1].Delay * 2
	case "fibonacci":
		if len(events) >= 2 {
			fibN1Delay := events[len(events)-1].Delay
			fibN2Delay := events[len(events)-2].Delay
			// Handle reset of delay ceiling which should cause
			// a new series to start
			if fibN2Delay == policy.MaxDelay && fibN1Delay == policy.Delay {
				delayDur = fibN1Delay
			} else {
				delayDur = fibN1Delay + fibN2Delay
			}
		}
	default:
		return delayDur
	}
	if policy.MaxDelay > 0 && delayDur > policy.MaxDelay {
		delayDur = policy.MaxDelay
		// check if delay needs to be reset

		lastRescheduleEvent := a.RescheduleTracker.Events[len(a.RescheduleTracker.Events)-1]
		timeDiff := a.LastEventTime().UTC().UnixNano() - lastRescheduleEvent.RescheduleTime
		if timeDiff > delayDur.Nanoseconds() {
			delayDur = policy.Delay
		}

	}

	return delayDur
}

// Terminated returns if the allocation is in a terminal state on a client.
func (a *Allocation) Terminated() bool {
	if a.ClientStatus == AllocClientStatusFailed ||
		a.ClientStatus == AllocClientStatusComplete ||
		a.ClientStatus == AllocClientStatusLost {
		return true
	}
	return false
}

// SetStopped updates the allocation in place to a DesiredStatus stop, with the ClientStatus
func (a *Allocation) SetStop(clientStatus, clientDesc string) {
	a.DesiredStatus = AllocDesiredStatusStop
	a.ClientStatus = clientStatus
	a.ClientDescription = clientDesc
	a.AppendState(AllocStateFieldClientStatus, clientStatus)
}

// AppendState creates and appends an AllocState entry recording the time of the state
// transition. Used to mark the transition to lost
func (a *Allocation) AppendState(field AllocStateField, value string) {
	a.AllocStates = append(a.AllocStates, &AllocState{
		Field: field,
		Value: value,
		Time:  time.Now().UTC(),
	})
}

// RanSuccessfully returns whether the client has ran the allocation and all
// tasks finished successfully. Critically this function returns whether the
// allocation has ran to completion and not just that the alloc has converged to
// its desired state. That is to say that a batch allocation must have finished
// with exit code 0 on all task groups. This doesn't really have meaning on a
// non-batch allocation because a service and system allocation should not
// finish.
func (a *Allocation) RanSuccessfully() bool {
	// Handle the case the client hasn't started the allocation.
	if len(a.TaskStates) == 0 {
		return false
	}

	// Check to see if all the tasks finished successfully in the allocation
	allSuccess := true
	for _, state := range a.TaskStates {
		allSuccess = allSuccess && state.Successful()
	}

	return allSuccess
}

// ShouldMigrate returns if the allocation needs data migration
func (a *Allocation) ShouldMigrate() bool {
	if a.PreviousAllocation == "" {
		return false
	}

	if a.DesiredStatus == AllocDesiredStatusStop || a.DesiredStatus == AllocDesiredStatusEvict {
		return false
	}

	tg := a.Job.LookupTaskGroup(a.TaskGroup)

	// if the task group is nil or the ephemeral disk block isn't present then
	// we won't migrate
	if tg == nil || tg.EphemeralDisk == nil {
		return false
	}

	// We won't migrate any data is the user hasn't enabled migration or the
	// disk is not marked as sticky
	if !tg.EphemeralDisk.Migrate || !tg.EphemeralDisk.Sticky {
		return false
	}

	return true
}

// SetEventDisplayMessage populates the display message if its not already set,
// a temporary fix to handle old allocations that don't have it.
// This method will be removed in a future release.
func (a *Allocation) SetEventDisplayMessages() {
	setDisplayMsg(a.TaskStates)
}

// COMPAT(0.11): Remove in 0.11
// ComparableResources returns the resources on the allocation
// handling upgrade paths. After 0.11 calls to this should be replaced with:
// alloc.AllocatedResources.Comparable()
func (a *Allocation) ComparableResources() *ComparableResources {
	// ALloc already has 0.9+ behavior
	if a.AllocatedResources != nil {
		return a.AllocatedResources.Comparable()
	}

	var resources *Resources
	if a.Resources != nil {
		resources = a.Resources
	} else if a.TaskResources != nil {
		resources = new(Resources)
		resources.Add(a.SharedResources)
		for _, taskResource := range a.TaskResources {
			resources.Add(taskResource)
		}
	}

	// Upgrade path
	return &ComparableResources{
		Flattened: AllocatedTaskResources{
			Cpu: AllocatedCpuResources{
				CpuShares: int64(resources.CPU),
			},
			Memory: AllocatedMemoryResources{
				MemoryMB: int64(resources.MemoryMB),
			},
			Networks: resources.Networks,
		},
		Shared: AllocatedSharedResources{
			DiskMB: int64(resources.DiskMB),
		},
	}
}

// LookupTask by name from the Allocation. Returns nil if the Job is not set, the
// TaskGroup does not exist, or the task name cannot be found.
func (a *Allocation) LookupTask(name string) *Task {
	if a.Job == nil {
		return nil
	}

	tg := a.Job.LookupTaskGroup(a.TaskGroup)
	if tg == nil {
		return nil
	}

	return tg.LookupTask(name)
}

// Stub returns a list stub for the allocation
func (a *Allocation) Stub(fields *AllocStubFields) *AllocListStub {
	s := &AllocListStub{
		ID:                    a.ID,
		EvalID:                a.EvalID,
		Name:                  a.Name,
		Namespace:             a.Namespace,
		NodeID:                a.NodeID,
		NodeName:              a.NodeName,
		JobID:                 a.JobID,
		JobType:               a.Job.Type,
		JobVersion:            a.Job.Version,
		TaskGroup:             a.TaskGroup,
		DesiredStatus:         a.DesiredStatus,
		DesiredDescription:    a.DesiredDescription,
		ClientStatus:          a.ClientStatus,
		ClientDescription:     a.ClientDescription,
		DesiredTransition:     a.DesiredTransition,
		TaskStates:            a.TaskStates,
		DeploymentStatus:      a.DeploymentStatus,
		FollowupEvalID:        a.FollowupEvalID,
		RescheduleTracker:     a.RescheduleTracker,
		PreemptedAllocations:  a.PreemptedAllocations,
		PreemptedByAllocation: a.PreemptedByAllocation,
		CreateIndex:           a.CreateIndex,
		ModifyIndex:           a.ModifyIndex,
		CreateTime:            a.CreateTime,
		ModifyTime:            a.ModifyTime,
	}

	if fields != nil {
		if fields.Resources {
			s.AllocatedResources = a.AllocatedResources
		}
		if !fields.TaskStates {
			s.TaskStates = nil
		}
	}

	return s
}

// AllocationDiff converts an Allocation type to an AllocationDiff type
// If at any time, modification are made to AllocationDiff so that an
// Allocation can no longer be safely converted to AllocationDiff,
// this method should be changed accordingly.
func (a *Allocation) AllocationDiff() *AllocationDiff {
	return (*AllocationDiff)(a)
}

// AllocationDiff is another named type for Allocation (to use the same fields),
// which is used to represent the delta for an Allocation. If you need a method
// defined on the al
type AllocationDiff Allocation

// AllocListStub is used to return a subset of alloc information
type AllocListStub struct {
	ID                    string
	EvalID                string
	Name                  string
	Namespace             string
	NodeID                string
	NodeName              string
	JobID                 string
	JobType               string
	JobVersion            uint64
	TaskGroup             string
	AllocatedResources    *AllocatedResources `json:",omitempty"`
	DesiredStatus         string
	DesiredDescription    string
	ClientStatus          string
	ClientDescription     string
	DesiredTransition     DesiredTransition
	TaskStates            map[string]*TaskState
	DeploymentStatus      *AllocDeploymentStatus
	FollowupEvalID        string
	RescheduleTracker     *RescheduleTracker
	PreemptedAllocations  []string
	PreemptedByAllocation string
	CreateIndex           uint64
	ModifyIndex           uint64
	CreateTime            int64
	ModifyTime            int64
}

// SetEventDisplayMessage populates the display message if its not already set,
// a temporary fix to handle old allocations that don't have it.
// This method will be removed in a future release.
func (a *AllocListStub) SetEventDisplayMessages() {
	setDisplayMsg(a.TaskStates)
}

func setDisplayMsg(taskStates map[string]*TaskState) {
	for _, taskState := range taskStates {
		for _, event := range taskState.Events {
			event.PopulateEventDisplayMessage()
		}
	}
}

// AllocStubFields defines which fields are included in the AllocListStub.
type AllocStubFields struct {
	// Resources includes resource-related fields if true.
	Resources bool

	// TaskStates removes the TaskStates field if false (default is to
	// include TaskStates).
	TaskStates bool
}

func NewAllocStubFields() *AllocStubFields {
	return &AllocStubFields{
		// Maintain backward compatibility by retaining task states by
		// default.
		TaskStates: true,
	}
}

// AllocMetric is used to track various metrics while attempting
// to make an allocation. These are used to debug a job, or to better
// understand the pressure within the system.
type AllocMetric struct {
	// NodesEvaluated is the number of nodes that were evaluated
	NodesEvaluated int

	// NodesFiltered is the number of nodes filtered due to a constraint
	NodesFiltered int

	// NodesAvailable is the number of nodes available for evaluation per DC.
	NodesAvailable map[string]int

	// ClassFiltered is the number of nodes filtered by class
	ClassFiltered map[string]int

	// ConstraintFiltered is the number of failures caused by constraint
	ConstraintFiltered map[string]int

	// NodesExhausted is the number of nodes skipped due to being
	// exhausted of at least one resource
	NodesExhausted int

	// ClassExhausted is the number of nodes exhausted by class
	ClassExhausted map[string]int

	// DimensionExhausted provides the count by dimension or reason
	DimensionExhausted map[string]int

	// QuotaExhausted provides the exhausted dimensions
	QuotaExhausted []string

	// Scores is the scores of the final few nodes remaining
	// for placement. The top score is typically selected.
	// Deprecated: Replaced by ScoreMetaData in Nomad 0.9
	Scores map[string]float64

	// ScoreMetaData is a slice of top scoring nodes displayed in the CLI
	ScoreMetaData []*NodeScoreMeta

	// nodeScoreMeta is used to keep scores for a single node id. It is cleared out after
	// we receive normalized score during the last step of the scoring stack.
	nodeScoreMeta *NodeScoreMeta

	// topScores is used to maintain a heap of the top K nodes with
	// the highest normalized score
	topScores *kheap.ScoreHeap

	// AllocationTime is a measure of how long the allocation
	// attempt took. This can affect performance and SLAs.
	AllocationTime time.Duration

	// CoalescedFailures indicates the number of other
	// allocations that were coalesced into this failed allocation.
	// This is to prevent creating many failed allocations for a
	// single task group.
	CoalescedFailures int
}

func (a *AllocMetric) Copy() *AllocMetric {
	if a == nil {
		return nil
	}
	na := new(AllocMetric)
	*na = *a
	na.NodesAvailable = helper.CopyMapStringInt(na.NodesAvailable)
	na.ClassFiltered = helper.CopyMapStringInt(na.ClassFiltered)
	na.ConstraintFiltered = helper.CopyMapStringInt(na.ConstraintFiltered)
	na.ClassExhausted = helper.CopyMapStringInt(na.ClassExhausted)
	na.DimensionExhausted = helper.CopyMapStringInt(na.DimensionExhausted)
	na.QuotaExhausted = helper.CopySliceString(na.QuotaExhausted)
	na.Scores = helper.CopyMapStringFloat64(na.Scores)
	na.ScoreMetaData = CopySliceNodeScoreMeta(na.ScoreMetaData)
	return na
}

func (a *AllocMetric) EvaluateNode() {
	a.NodesEvaluated += 1
}

func (a *AllocMetric) FilterNode(node *Node, constraint string) {
	a.NodesFiltered += 1
	if node != nil && node.NodeClass != "" {
		if a.ClassFiltered == nil {
			a.ClassFiltered = make(map[string]int)
		}
		a.ClassFiltered[node.NodeClass] += 1
	}
	if constraint != "" {
		if a.ConstraintFiltered == nil {
			a.ConstraintFiltered = make(map[string]int)
		}
		a.ConstraintFiltered[constraint] += 1
	}
}

func (a *AllocMetric) ExhaustedNode(node *Node, dimension string) {
	a.NodesExhausted += 1
	if node != nil && node.NodeClass != "" {
		if a.ClassExhausted == nil {
			a.ClassExhausted = make(map[string]int)
		}
		a.ClassExhausted[node.NodeClass] += 1
	}
	if dimension != "" {
		if a.DimensionExhausted == nil {
			a.DimensionExhausted = make(map[string]int)
		}
		a.DimensionExhausted[dimension] += 1
	}
}

func (a *AllocMetric) ExhaustQuota(dimensions []string) {
	if a.QuotaExhausted == nil {
		a.QuotaExhausted = make([]string, 0, len(dimensions))
	}

	a.QuotaExhausted = append(a.QuotaExhausted, dimensions...)
}

// ScoreNode is used to gather top K scoring nodes in a heap
func (a *AllocMetric) ScoreNode(node *Node, name string, score float64) {
	// Create nodeScoreMeta lazily if its the first time or if its a new node
	if a.nodeScoreMeta == nil || a.nodeScoreMeta.NodeID != node.ID {
		a.nodeScoreMeta = &NodeScoreMeta{
			NodeID: node.ID,
			Scores: make(map[string]float64),
		}
	}
	if name == NormScorerName {
		a.nodeScoreMeta.NormScore = score
		// Once we have the normalized score we can push to the heap
		// that tracks top K by normalized score

		// Create the heap if its not there already
		if a.topScores == nil {
			a.topScores = kheap.NewScoreHeap(MaxRetainedNodeScores)
		}
		heap.Push(a.topScores, a.nodeScoreMeta)

		// Clear out this entry because its now in the heap
		a.nodeScoreMeta = nil
	} else {
		a.nodeScoreMeta.Scores[name] = score
	}
}

// PopulateScoreMetaData populates a map of scorer to scoring metadata
// The map is populated by popping elements from a heap of top K scores
// maintained per scorer
func (a *AllocMetric) PopulateScoreMetaData() {
	if a.topScores == nil {
		return
	}

	if a.ScoreMetaData == nil {
		a.ScoreMetaData = make([]*NodeScoreMeta, a.topScores.Len())
	}
	heapItems := a.topScores.GetItemsReverse()
	for i, item := range heapItems {
		a.ScoreMetaData[i] = item.(*NodeScoreMeta)
	}
}

// NodeScoreMeta captures scoring meta data derived from
// different scoring factors.
type NodeScoreMeta struct {
	NodeID    string
	Scores    map[string]float64
	NormScore float64
}

func (s *NodeScoreMeta) Copy() *NodeScoreMeta {
	if s == nil {
		return nil
	}
	ns := new(NodeScoreMeta)
	*ns = *s
	return ns
}

func (s *NodeScoreMeta) String() string {
	return fmt.Sprintf("%s %f %v", s.NodeID, s.NormScore, s.Scores)
}

func (s *NodeScoreMeta) Score() float64 {
	return s.NormScore
}

func (s *NodeScoreMeta) Data() interface{} {
	return s
}

// AllocNetworkStatus captures the status of an allocation's network during runtime.
// Depending on the network mode, an allocation's address may need to be known to other
// systems in Nomad such as service registration.
type AllocNetworkStatus struct {
	InterfaceName string
	Address       string
	DNS           *DNSConfig
}

func (a *AllocNetworkStatus) Copy() *AllocNetworkStatus {
	if a == nil {
		return nil
	}
	return &AllocNetworkStatus{
		InterfaceName: a.InterfaceName,
		Address:       a.Address,
		DNS:           a.DNS.Copy(),
	}
}

// AllocDeploymentStatus captures the status of the allocation as part of the
// deployment. This can include things like if the allocation has been marked as
// healthy.
type AllocDeploymentStatus struct {
	// Healthy marks whether the allocation has been marked healthy or unhealthy
	// as part of a deployment. It can be unset if it has neither been marked
	// healthy or unhealthy.
	Healthy *bool

	// Timestamp is the time at which the health status was set.
	Timestamp time.Time

	// Canary marks whether the allocation is a canary or not. A canary that has
	// been promoted will have this field set to false.
	Canary bool

	// ModifyIndex is the raft index in which the deployment status was last
	// changed.
	ModifyIndex uint64
}

// HasHealth returns true if the allocation has its health set.
func (a *AllocDeploymentStatus) HasHealth() bool {
	return a != nil && a.Healthy != nil
}

// IsHealthy returns if the allocation is marked as healthy as part of a
// deployment
func (a *AllocDeploymentStatus) IsHealthy() bool {
	if a == nil {
		return false
	}

	return a.Healthy != nil && *a.Healthy
}

// IsUnhealthy returns if the allocation is marked as unhealthy as part of a
// deployment
func (a *AllocDeploymentStatus) IsUnhealthy() bool {
	if a == nil {
		return false
	}

	return a.Healthy != nil && !*a.Healthy
}

// IsCanary returns if the allocation is marked as a canary
func (a *AllocDeploymentStatus) IsCanary() bool {
	if a == nil {
		return false
	}

	return a.Canary
}

func (a *AllocDeploymentStatus) Copy() *AllocDeploymentStatus {
	if a == nil {
		return nil
	}

	c := new(AllocDeploymentStatus)
	*c = *a

	if a.Healthy != nil {
		c.Healthy = helper.BoolToPtr(*a.Healthy)
	}

	return c
}

const (
	EvalStatusBlocked   = "blocked"
	EvalStatusPending   = "pending"
	EvalStatusComplete  = "complete"
	EvalStatusFailed    = "failed"
	EvalStatusCancelled = "canceled"
)

const (
	EvalTriggerJobRegister       = "job-register"
	EvalTriggerJobDeregister     = "job-deregister"
	EvalTriggerPeriodicJob       = "periodic-job"
	EvalTriggerNodeDrain         = "node-drain"
	EvalTriggerNodeUpdate        = "node-update"
	EvalTriggerAllocStop         = "alloc-stop"
	EvalTriggerScheduled         = "scheduled"
	EvalTriggerRollingUpdate     = "rolling-update"
	EvalTriggerDeploymentWatcher = "deployment-watcher"
	EvalTriggerFailedFollowUp    = "failed-follow-up"
	EvalTriggerMaxPlans          = "max-plan-attempts"
	EvalTriggerRetryFailedAlloc  = "alloc-failure"
	EvalTriggerQueuedAllocs      = "queued-allocs"
	EvalTriggerPreemption        = "preemption"
	EvalTriggerScaling           = "job-scaling"
)

const (
	// CoreJobEvalGC is used for the garbage collection of evaluations
	// and allocations. We periodically scan evaluations in a terminal state,
	// in which all the corresponding allocations are also terminal. We
	// delete these out of the system to bound the state.
	CoreJobEvalGC = "eval-gc"

	// CoreJobNodeGC is used for the garbage collection of failed nodes.
	// We periodically scan nodes in a terminal state, and if they have no
	// corresponding allocations we delete these out of the system.
	CoreJobNodeGC = "node-gc"

	// CoreJobJobGC is used for the garbage collection of eligible jobs. We
	// periodically scan garbage collectible jobs and check if both their
	// evaluations and allocations are terminal. If so, we delete these out of
	// the system.
	CoreJobJobGC = "job-gc"

	// CoreJobDeploymentGC is used for the garbage collection of eligible
	// deployments. We periodically scan garbage collectible deployments and
	// check if they are terminal. If so, we delete these out of the system.
	CoreJobDeploymentGC = "deployment-gc"

	// CoreJobCSIVolumeClaimGC is use for the garbage collection of CSI
	// volume claims. We periodically scan volumes to see if no allocs are
	// claiming them. If so, we unclaim the volume.
	CoreJobCSIVolumeClaimGC = "csi-volume-claim-gc"

	// CoreJobCSIPluginGC is use for the garbage collection of CSI plugins.
	// We periodically scan plugins to see if they have no associated volumes
	// or allocs running them. If so, we delete the plugin.
	CoreJobCSIPluginGC = "csi-plugin-gc"

	// CoreJobForceGC is used to force garbage collection of all GCable objects.
	CoreJobForceGC = "force-gc"
)

// Evaluation is used anytime we need to apply business logic as a result
// of a change to our desired state (job specification) or the emergent state
// (registered nodes). When the inputs change, we need to "evaluate" them,
// potentially taking action (allocation of work) or doing nothing if the state
// of the world does not require it.
type Evaluation struct {
	// msgpack omit empty fields during serialization
	_struct bool `codec:",omitempty"` // nolint: structcheck

	// ID is a randomly generated UUID used for this evaluation. This
	// is assigned upon the creation of the evaluation.
	ID string

	// Namespace is the namespace the evaluation is created in
	Namespace string

	// Priority is used to control scheduling importance and if this job
	// can preempt other jobs.
	Priority int

	// Type is used to control which schedulers are available to handle
	// this evaluation.
	Type string

	// TriggeredBy is used to give some insight into why this Eval
	// was created. (Job change, node failure, alloc failure, etc).
	TriggeredBy string

	// JobID is the job this evaluation is scoped to. Evaluations cannot
	// be run in parallel for a given JobID, so we serialize on this.
	JobID string

	// JobModifyIndex is the modify index of the job at the time
	// the evaluation was created
	JobModifyIndex uint64

	// NodeID is the node that was affected triggering the evaluation.
	NodeID string

	// NodeModifyIndex is the modify index of the node at the time
	// the evaluation was created
	NodeModifyIndex uint64

	// DeploymentID is the ID of the deployment that triggered the evaluation.
	DeploymentID string

	// Status of the evaluation
	Status string

	// StatusDescription is meant to provide more human useful information
	StatusDescription string

	// Wait is a minimum wait time for running the eval. This is used to
	// support a rolling upgrade in versions prior to 0.7.0
	// Deprecated
	Wait time.Duration

	// WaitUntil is the time when this eval should be run. This is used to
	// supported delayed rescheduling of failed allocations
	WaitUntil time.Time

	// NextEval is the evaluation ID for the eval created to do a followup.
	// This is used to support rolling upgrades and failed-follow-up evals, where
	// we need a chain of evaluations.
	NextEval string

	// PreviousEval is the evaluation ID for the eval creating this one to do a followup.
	// This is used to support rolling upgrades and failed-follow-up evals, where
	// we need a chain of evaluations.
	PreviousEval string

	// BlockedEval is the evaluation ID for a created blocked eval. A
	// blocked eval will be created if all allocations could not be placed due
	// to constraints or lacking resources.
	BlockedEval string

	// FailedTGAllocs are task groups which have allocations that could not be
	// made, but the metrics are persisted so that the user can use the feedback
	// to determine the cause.
	FailedTGAllocs map[string]*AllocMetric

	// ClassEligibility tracks computed node classes that have been explicitly
	// marked as eligible or ineligible.
	ClassEligibility map[string]bool

	// QuotaLimitReached marks whether a quota limit was reached for the
	// evaluation.
	QuotaLimitReached string

	// EscapedComputedClass marks whether the job has constraints that are not
	// captured by computed node classes.
	EscapedComputedClass bool

	// AnnotatePlan triggers the scheduler to provide additional annotations
	// during the evaluation. This should not be set during normal operations.
	AnnotatePlan bool

	// QueuedAllocations is the number of unplaced allocations at the time the
	// evaluation was processed. The map is keyed by Task Group names.
	QueuedAllocations map[string]int

	// LeaderACL provides the ACL token to when issuing RPCs back to the
	// leader. This will be a valid management token as long as the leader is
	// active. This should not ever be exposed via the API.
	LeaderACL string

	// SnapshotIndex is the Raft index of the snapshot used to process the
	// evaluation. The index will either be set when it has gone through the
	// scheduler or if a blocked evaluation is being created. The index is set
	// in this case so we can determine if an early unblocking is required since
	// capacity has changed since the evaluation was created. This can result in
	// the SnapshotIndex being less than the CreateIndex.
	SnapshotIndex uint64

	// Raft Indexes
	CreateIndex uint64
	ModifyIndex uint64

	CreateTime int64
	ModifyTime int64
}

// TerminalStatus returns if the current status is terminal and
// will no longer transition.
func (e *Evaluation) TerminalStatus() bool {
	switch e.Status {
	case EvalStatusComplete, EvalStatusFailed, EvalStatusCancelled:
		return true
	default:
		return false
	}
}

func (e *Evaluation) GoString() string {
	return fmt.Sprintf("<Eval %q JobID: %q Namespace: %q>", e.ID, e.JobID, e.Namespace)
}

func (e *Evaluation) Copy() *Evaluation {
	if e == nil {
		return nil
	}
	ne := new(Evaluation)
	*ne = *e

	// Copy ClassEligibility
	if e.ClassEligibility != nil {
		classes := make(map[string]bool, len(e.ClassEligibility))
		for class, elig := range e.ClassEligibility {
			classes[class] = elig
		}
		ne.ClassEligibility = classes
	}

	// Copy FailedTGAllocs
	if e.FailedTGAllocs != nil {
		failedTGs := make(map[string]*AllocMetric, len(e.FailedTGAllocs))
		for tg, metric := range e.FailedTGAllocs {
			failedTGs[tg] = metric.Copy()
		}
		ne.FailedTGAllocs = failedTGs
	}

	// Copy queued allocations
	if e.QueuedAllocations != nil {
		queuedAllocations := make(map[string]int, len(e.QueuedAllocations))
		for tg, num := range e.QueuedAllocations {
			queuedAllocations[tg] = num
		}
		ne.QueuedAllocations = queuedAllocations
	}

	return ne
}

// ShouldEnqueue checks if a given evaluation should be enqueued into the
// eval_broker
func (e *Evaluation) ShouldEnqueue() bool {
	switch e.Status {
	case EvalStatusPending:
		return true
	case EvalStatusComplete, EvalStatusFailed, EvalStatusBlocked, EvalStatusCancelled:
		return false
	default:
		panic(fmt.Sprintf("unhandled evaluation (%s) status %s", e.ID, e.Status))
	}
}

// ShouldBlock checks if a given evaluation should be entered into the blocked
// eval tracker.
func (e *Evaluation) ShouldBlock() bool {
	switch e.Status {
	case EvalStatusBlocked:
		return true
	case EvalStatusComplete, EvalStatusFailed, EvalStatusPending, EvalStatusCancelled:
		return false
	default:
		panic(fmt.Sprintf("unhandled evaluation (%s) status %s", e.ID, e.Status))
	}
}

// MakePlan is used to make a plan from the given evaluation
// for a given Job
func (e *Evaluation) MakePlan(j *Job) *Plan {
	p := &Plan{
		EvalID:          e.ID,
		Priority:        e.Priority,
		Job:             j,
		NodeUpdate:      make(map[string][]*Allocation),
		NodeAllocation:  make(map[string][]*Allocation),
		NodePreemptions: make(map[string][]*Allocation),
	}
	if j != nil {
		p.AllAtOnce = j.AllAtOnce
	}
	return p
}

// NextRollingEval creates an evaluation to followup this eval for rolling updates
func (e *Evaluation) NextRollingEval(wait time.Duration) *Evaluation {
	now := time.Now().UTC().UnixNano()
	return &Evaluation{
		ID:             uuid.Generate(),
		Namespace:      e.Namespace,
		Priority:       e.Priority,
		Type:           e.Type,
		TriggeredBy:    EvalTriggerRollingUpdate,
		JobID:          e.JobID,
		JobModifyIndex: e.JobModifyIndex,
		Status:         EvalStatusPending,
		Wait:           wait,
		PreviousEval:   e.ID,
		CreateTime:     now,
		ModifyTime:     now,
	}
}

// CreateBlockedEval creates a blocked evaluation to followup this eval to place any
// failed allocations. It takes the classes marked explicitly eligible or
// ineligible, whether the job has escaped computed node classes and whether the
// quota limit was reached.
func (e *Evaluation) CreateBlockedEval(classEligibility map[string]bool,
	escaped bool, quotaReached string) *Evaluation {
	now := time.Now().UTC().UnixNano()
	return &Evaluation{
		ID:                   uuid.Generate(),
		Namespace:            e.Namespace,
		Priority:             e.Priority,
		Type:                 e.Type,
		TriggeredBy:          EvalTriggerQueuedAllocs,
		JobID:                e.JobID,
		JobModifyIndex:       e.JobModifyIndex,
		Status:               EvalStatusBlocked,
		PreviousEval:         e.ID,
		ClassEligibility:     classEligibility,
		EscapedComputedClass: escaped,
		QuotaLimitReached:    quotaReached,
		CreateTime:           now,
		ModifyTime:           now,
	}
}

// CreateFailedFollowUpEval creates a follow up evaluation when the current one
// has been marked as failed because it has hit the delivery limit and will not
// be retried by the eval_broker. Callers should copy the created eval's ID to
// into the old eval's NextEval field.
func (e *Evaluation) CreateFailedFollowUpEval(wait time.Duration) *Evaluation {
	now := time.Now().UTC().UnixNano()
	return &Evaluation{
		ID:             uuid.Generate(),
		Namespace:      e.Namespace,
		Priority:       e.Priority,
		Type:           e.Type,
		TriggeredBy:    EvalTriggerFailedFollowUp,
		JobID:          e.JobID,
		JobModifyIndex: e.JobModifyIndex,
		Status:         EvalStatusPending,
		Wait:           wait,
		PreviousEval:   e.ID,
		CreateTime:     now,
		ModifyTime:     now,
	}
}

// UpdateModifyTime takes into account that clocks on different servers may be
// slightly out of sync. Even in case of a leader change, this method will
// guarantee that ModifyTime will always be after CreateTime.
func (e *Evaluation) UpdateModifyTime() {
	now := time.Now().UTC().UnixNano()
	if now <= e.CreateTime {
		e.ModifyTime = e.CreateTime + 1
	} else {
		e.ModifyTime = now
	}
}

// Plan is used to submit a commit plan for task allocations. These
// are submitted to the leader which verifies that resources have
// not been overcommitted before admitting the plan.
type Plan struct {
	// msgpack omit empty fields during serialization
	_struct bool `codec:",omitempty"` // nolint: structcheck

	// EvalID is the evaluation ID this plan is associated with
	EvalID string

	// EvalToken is used to prevent a split-brain processing of
	// an evaluation. There should only be a single scheduler running
	// an Eval at a time, but this could be violated after a leadership
	// transition. This unique token is used to reject plans that are
	// being submitted from a different leader.
	EvalToken string

	// Priority is the priority of the upstream job
	Priority int

	// AllAtOnce is used to control if incremental scheduling of task groups
	// is allowed or if we must do a gang scheduling of the entire job.
	// If this is false, a plan may be partially applied. Otherwise, the
	// entire plan must be able to make progress.
	AllAtOnce bool

	// Job is the parent job of all the allocations in the Plan.
	// Since a Plan only involves a single Job, we can reduce the size
	// of the plan by only including it once.
	Job *Job

	// NodeUpdate contains all the allocations for each node. For each node,
	// this is a list of the allocations to update to either stop or evict.
	NodeUpdate map[string][]*Allocation

	// NodeAllocation contains all the allocations for each node.
	// The evicts must be considered prior to the allocations.
	NodeAllocation map[string][]*Allocation

	// Annotations contains annotations by the scheduler to be used by operators
	// to understand the decisions made by the scheduler.
	Annotations *PlanAnnotations

	// Deployment is the deployment created or updated by the scheduler that
	// should be applied by the planner.
	Deployment *Deployment

	// DeploymentUpdates is a set of status updates to apply to the given
	// deployments. This allows the scheduler to cancel any unneeded deployment
	// because the job is stopped or the update block is removed.
	DeploymentUpdates []*DeploymentStatusUpdate

	// NodePreemptions is a map from node id to a set of allocations from other
	// lower priority jobs that are preempted. Preempted allocations are marked
	// as evicted.
	NodePreemptions map[string][]*Allocation

	// SnapshotIndex is the Raft index of the snapshot used to create the
	// Plan. The leader will wait to evaluate the plan until its StateStore
	// has reached at least this index.
	SnapshotIndex uint64
}

// AppendStoppedAlloc marks an allocation to be stopped. The clientStatus of the
// allocation may be optionally set by passing in a non-empty value.
func (p *Plan) AppendStoppedAlloc(alloc *Allocation, desiredDesc, clientStatus, followupEvalID string) {
	newAlloc := new(Allocation)
	*newAlloc = *alloc

	// If the job is not set in the plan we are deregistering a job so we
	// extract the job from the allocation.
	if p.Job == nil && newAlloc.Job != nil {
		p.Job = newAlloc.Job
	}

	// Normalize the job
	newAlloc.Job = nil

	// Strip the resources as it can be rebuilt.
	newAlloc.Resources = nil

	newAlloc.DesiredStatus = AllocDesiredStatusStop
	newAlloc.DesiredDescription = desiredDesc

	if clientStatus != "" {
		newAlloc.ClientStatus = clientStatus
	}

	newAlloc.AppendState(AllocStateFieldClientStatus, clientStatus)

	if followupEvalID != "" {
		newAlloc.FollowupEvalID = followupEvalID
	}

	node := alloc.NodeID
	existing := p.NodeUpdate[node]
	p.NodeUpdate[node] = append(existing, newAlloc)
}

// AppendPreemptedAlloc is used to append an allocation that's being preempted to the plan.
// To minimize the size of the plan, this only sets a minimal set of fields in the allocation
func (p *Plan) AppendPreemptedAlloc(alloc *Allocation, preemptingAllocID string) {
	newAlloc := &Allocation{}
	newAlloc.ID = alloc.ID
	newAlloc.JobID = alloc.JobID
	newAlloc.Namespace = alloc.Namespace
	newAlloc.DesiredStatus = AllocDesiredStatusEvict
	newAlloc.PreemptedByAllocation = preemptingAllocID

	desiredDesc := fmt.Sprintf("Preempted by alloc ID %v", preemptingAllocID)
	newAlloc.DesiredDescription = desiredDesc

	// TaskResources are needed by the plan applier to check if allocations fit
	// after removing preempted allocations
	if alloc.AllocatedResources != nil {
		newAlloc.AllocatedResources = alloc.AllocatedResources
	} else {
		// COMPAT Remove in version 0.11
		newAlloc.TaskResources = alloc.TaskResources
		newAlloc.SharedResources = alloc.SharedResources
	}

	// Append this alloc to slice for this node
	node := alloc.NodeID
	existing := p.NodePreemptions[node]
	p.NodePreemptions[node] = append(existing, newAlloc)
}

func (p *Plan) PopUpdate(alloc *Allocation) {
	existing := p.NodeUpdate[alloc.NodeID]
	n := len(existing)
	if n > 0 && existing[n-1].ID == alloc.ID {
		existing = existing[:n-1]
		if len(existing) > 0 {
			p.NodeUpdate[alloc.NodeID] = existing
		} else {
			delete(p.NodeUpdate, alloc.NodeID)
		}
	}
}

// AppendAlloc appends the alloc to the plan allocations.
// Uses the passed job if explicitly passed, otherwise
// it is assumed the alloc will use the plan Job version.
func (p *Plan) AppendAlloc(alloc *Allocation, job *Job) {
	node := alloc.NodeID
	existing := p.NodeAllocation[node]

	alloc.Job = job

	p.NodeAllocation[node] = append(existing, alloc)
}

// IsNoOp checks if this plan would do nothing
func (p *Plan) IsNoOp() bool {
	return len(p.NodeUpdate) == 0 &&
		len(p.NodeAllocation) == 0 &&
		p.Deployment == nil &&
		len(p.DeploymentUpdates) == 0
}

// NormalizeAllocations normalizes allocations to remove fields that can
// be fetched from the MemDB instead of sending over the wire
func (p *Plan) NormalizeAllocations() {
	for _, allocs := range p.NodeUpdate {
		for i, alloc := range allocs {
			allocs[i] = &Allocation{
				ID:                 alloc.ID,
				DesiredDescription: alloc.DesiredDescription,
				ClientStatus:       alloc.ClientStatus,
				FollowupEvalID:     alloc.FollowupEvalID,
			}
		}
	}

	for _, allocs := range p.NodePreemptions {
		for i, alloc := range allocs {
			allocs[i] = &Allocation{
				ID:                    alloc.ID,
				PreemptedByAllocation: alloc.PreemptedByAllocation,
			}
		}
	}
}

// PlanResult is the result of a plan submitted to the leader.
type PlanResult struct {
	// NodeUpdate contains all the updates that were committed.
	NodeUpdate map[string][]*Allocation

	// NodeAllocation contains all the allocations that were committed.
	NodeAllocation map[string][]*Allocation

	// Deployment is the deployment that was committed.
	Deployment *Deployment

	// DeploymentUpdates is the set of deployment updates that were committed.
	DeploymentUpdates []*DeploymentStatusUpdate

	// NodePreemptions is a map from node id to a set of allocations from other
	// lower priority jobs that are preempted. Preempted allocations are marked
	// as stopped.
	NodePreemptions map[string][]*Allocation

	// RefreshIndex is the index the worker should refresh state up to.
	// This allows all evictions and allocations to be materialized.
	// If any allocations were rejected due to stale data (node state,
	// over committed) this can be used to force a worker refresh.
	RefreshIndex uint64

	// AllocIndex is the Raft index in which the evictions and
	// allocations took place. This is used for the write index.
	AllocIndex uint64
}

// IsNoOp checks if this plan result would do nothing
func (p *PlanResult) IsNoOp() bool {
	return len(p.NodeUpdate) == 0 && len(p.NodeAllocation) == 0 &&
		len(p.DeploymentUpdates) == 0 && p.Deployment == nil
}

// FullCommit is used to check if all the allocations in a plan
// were committed as part of the result. Returns if there was
// a match, and the number of expected and actual allocations.
func (p *PlanResult) FullCommit(plan *Plan) (bool, int, int) {
	expected := 0
	actual := 0
	for name, allocList := range plan.NodeAllocation {
		didAlloc := p.NodeAllocation[name]
		expected += len(allocList)
		actual += len(didAlloc)
	}
	return actual == expected, expected, actual
}

// PlanAnnotations holds annotations made by the scheduler to give further debug
// information to operators.
type PlanAnnotations struct {
	// DesiredTGUpdates is the set of desired updates per task group.
	DesiredTGUpdates map[string]*DesiredUpdates

	// PreemptedAllocs is the set of allocations to be preempted to make the placement successful.
	PreemptedAllocs []*AllocListStub
}

// DesiredUpdates is the set of changes the scheduler would like to make given
// sufficient resources and cluster capacity.
type DesiredUpdates struct {
	Ignore            uint64
	Place             uint64
	Migrate           uint64
	Stop              uint64
	InPlaceUpdate     uint64
	DestructiveUpdate uint64
	Canary            uint64
	Preemptions       uint64
}

func (d *DesiredUpdates) GoString() string {
	return fmt.Sprintf("(place %d) (inplace %d) (destructive %d) (stop %d) (migrate %d) (ignore %d) (canary %d)",
		d.Place, d.InPlaceUpdate, d.DestructiveUpdate, d.Stop, d.Migrate, d.Ignore, d.Canary)
}

// msgpackHandle is a shared handle for encoding/decoding of structs
var MsgpackHandle = func() *codec.MsgpackHandle {
	h := &codec.MsgpackHandle{}
	h.RawToString = true

	// maintain binary format from time prior to upgrading latest ugorji
	h.BasicHandle.TimeNotBuiltin = true

	// Sets the default type for decoding a map into a nil interface{}.
	// This is necessary in particular because we store the driver configs as a
	// nil interface{}.
	h.MapType = reflect.TypeOf(map[string]interface{}(nil))

	// only review struct codec tags
	h.TypeInfos = codec.NewTypeInfos([]string{"codec"})

	return h
}()

var (
	// JsonHandle and JsonHandlePretty are the codec handles to JSON encode
	// structs. The pretty handle will add indents for easier human consumption.
	JsonHandle = &codec.JsonHandle{
		HTMLCharsAsIs: true,
	}
	JsonHandlePretty = &codec.JsonHandle{
		HTMLCharsAsIs: true,
		Indent:        4,
	}
)

// Decode is used to decode a MsgPack encoded object
func Decode(buf []byte, out interface{}) error {
	return codec.NewDecoder(bytes.NewReader(buf), MsgpackHandle).Decode(out)
}

// Encode is used to encode a MsgPack object with type prefix
func Encode(t MessageType, msg interface{}) ([]byte, error) {
	var buf bytes.Buffer
	buf.WriteByte(uint8(t))
	err := codec.NewEncoder(&buf, MsgpackHandle).Encode(msg)
	return buf.Bytes(), err
}

// KeyringResponse is a unified key response and can be used for install,
// remove, use, as well as listing key queries.
type KeyringResponse struct {
	Messages map[string]string
	Keys     map[string]int
	NumNodes int
}

// KeyringRequest is request objects for serf key operations.
type KeyringRequest struct {
	Key string
}

// RecoverableError wraps an error and marks whether it is recoverable and could
// be retried or it is fatal.
type RecoverableError struct {
	Err         string
	Recoverable bool
}

// NewRecoverableError is used to wrap an error and mark it as recoverable or
// not.
func NewRecoverableError(e error, recoverable bool) error {
	if e == nil {
		return nil
	}

	return &RecoverableError{
		Err:         e.Error(),
		Recoverable: recoverable,
	}
}

// WrapRecoverable wraps an existing error in a new RecoverableError with a new
// message. If the error was recoverable before the returned error is as well;
// otherwise it is unrecoverable.
func WrapRecoverable(msg string, err error) error {
	return &RecoverableError{Err: msg, Recoverable: IsRecoverable(err)}
}

func (r *RecoverableError) Error() string {
	return r.Err
}

func (r *RecoverableError) IsRecoverable() bool {
	return r.Recoverable
}

func (r *RecoverableError) IsUnrecoverable() bool {
	return !r.Recoverable
}

// Recoverable is an interface for errors to implement to indicate whether or
// not they are fatal or recoverable.
type Recoverable interface {
	error
	IsRecoverable() bool
}

// IsRecoverable returns true if error is a RecoverableError with
// Recoverable=true. Otherwise false is returned.
func IsRecoverable(e error) bool {
	if re, ok := e.(Recoverable); ok {
		return re.IsRecoverable()
	}
	return false
}

// WrappedServerError wraps an error and satisfies
// both the Recoverable and the ServerSideError interfaces
type WrappedServerError struct {
	Err error
}

// NewWrappedServerError is used to create a wrapped server side error
func NewWrappedServerError(e error) error {
	return &WrappedServerError{
		Err: e,
	}
}

func (r *WrappedServerError) IsRecoverable() bool {
	return IsRecoverable(r.Err)
}

func (r *WrappedServerError) Error() string {
	return r.Err.Error()
}

func (r *WrappedServerError) IsServerSide() bool {
	return true
}

// ServerSideError is an interface for errors to implement to indicate
// errors occurring after the request makes it to a server
type ServerSideError interface {
	error
	IsServerSide() bool
}

// IsServerSide returns true if error is a wrapped
// server side error
func IsServerSide(e error) bool {
	if se, ok := e.(ServerSideError); ok {
		return se.IsServerSide()
	}
	return false
}

// ACLPolicy is used to represent an ACL policy
type ACLPolicy struct {
	Name        string      // Unique name
	Description string      // Human readable
	Rules       string      // HCL or JSON format
	RulesJSON   *acl.Policy // Generated from Rules on read
	Hash        []byte
	CreateIndex uint64
	ModifyIndex uint64
}

// SetHash is used to compute and set the hash of the ACL policy
func (c *ACLPolicy) SetHash() []byte {
	// Initialize a 256bit Blake2 hash (32 bytes)
	hash, err := blake2b.New256(nil)
	if err != nil {
		panic(err)
	}

	// Write all the user set fields
	_, _ = hash.Write([]byte(c.Name))
	_, _ = hash.Write([]byte(c.Description))
	_, _ = hash.Write([]byte(c.Rules))

	// Finalize the hash
	hashVal := hash.Sum(nil)

	// Set and return the hash
	c.Hash = hashVal
	return hashVal
}

func (a *ACLPolicy) Stub() *ACLPolicyListStub {
	return &ACLPolicyListStub{
		Name:        a.Name,
		Description: a.Description,
		Hash:        a.Hash,
		CreateIndex: a.CreateIndex,
		ModifyIndex: a.ModifyIndex,
	}
}

func (a *ACLPolicy) Validate() error {
	var mErr multierror.Error
	if !validPolicyName.MatchString(a.Name) {
		err := fmt.Errorf("invalid name '%s'", a.Name)
		mErr.Errors = append(mErr.Errors, err)
	}
	if _, err := acl.Parse(a.Rules); err != nil {
		err = fmt.Errorf("failed to parse rules: %v", err)
		mErr.Errors = append(mErr.Errors, err)
	}
	if len(a.Description) > maxPolicyDescriptionLength {
		err := fmt.Errorf("description longer than %d", maxPolicyDescriptionLength)
		mErr.Errors = append(mErr.Errors, err)
	}
	return mErr.ErrorOrNil()
}

// ACLPolicyListStub is used to for listing ACL policies
type ACLPolicyListStub struct {
	Name        string
	Description string
	Hash        []byte
	CreateIndex uint64
	ModifyIndex uint64
}

// ACLPolicyListRequest is used to request a list of policies
type ACLPolicyListRequest struct {
	QueryOptions
}

// ACLPolicySpecificRequest is used to query a specific policy
type ACLPolicySpecificRequest struct {
	Name string
	QueryOptions
}

// ACLPolicySetRequest is used to query a set of policies
type ACLPolicySetRequest struct {
	Names []string
	QueryOptions
}

// ACLPolicyListResponse is used for a list request
type ACLPolicyListResponse struct {
	Policies []*ACLPolicyListStub
	QueryMeta
}

// SingleACLPolicyResponse is used to return a single policy
type SingleACLPolicyResponse struct {
	Policy *ACLPolicy
	QueryMeta
}

// ACLPolicySetResponse is used to return a set of policies
type ACLPolicySetResponse struct {
	Policies map[string]*ACLPolicy
	QueryMeta
}

// ACLPolicyDeleteRequest is used to delete a set of policies
type ACLPolicyDeleteRequest struct {
	Names []string
	WriteRequest
}

// ACLPolicyUpsertRequest is used to upsert a set of policies
type ACLPolicyUpsertRequest struct {
	Policies []*ACLPolicy
	WriteRequest
}

// ACLToken represents a client token which is used to Authenticate
type ACLToken struct {
	AccessorID  string   // Public Accessor ID (UUID)
	SecretID    string   // Secret ID, private (UUID)
	Name        string   // Human friendly name
	Type        string   // Client or Management
	Policies    []string // Policies this token ties to
	Global      bool     // Global or Region local
	Hash        []byte
	CreateTime  time.Time // Time of creation
	CreateIndex uint64
	ModifyIndex uint64
}

func (a *ACLToken) Copy() *ACLToken {
	c := new(ACLToken)
	*c = *a

	c.Policies = make([]string, len(a.Policies))
	copy(c.Policies, a.Policies)
	c.Hash = make([]byte, len(a.Hash))
	copy(c.Hash, a.Hash)

	return c
}

var (
	// AnonymousACLToken is used no SecretID is provided, and the
	// request is made anonymously.
	AnonymousACLToken = &ACLToken{
		AccessorID: "anonymous",
		Name:       "Anonymous Token",
		Type:       ACLClientToken,
		Policies:   []string{"anonymous"},
		Global:     false,
	}
)

type ACLTokenListStub struct {
	AccessorID  string
	Name        string
	Type        string
	Policies    []string
	Global      bool
	Hash        []byte
	CreateTime  time.Time
	CreateIndex uint64
	ModifyIndex uint64
}

// SetHash is used to compute and set the hash of the ACL token
func (a *ACLToken) SetHash() []byte {
	// Initialize a 256bit Blake2 hash (32 bytes)
	hash, err := blake2b.New256(nil)
	if err != nil {
		panic(err)
	}

	// Write all the user set fields
	_, _ = hash.Write([]byte(a.Name))
	_, _ = hash.Write([]byte(a.Type))
	for _, policyName := range a.Policies {
		_, _ = hash.Write([]byte(policyName))
	}
	if a.Global {
		_, _ = hash.Write([]byte("global"))
	} else {
		_, _ = hash.Write([]byte("local"))
	}

	// Finalize the hash
	hashVal := hash.Sum(nil)

	// Set and return the hash
	a.Hash = hashVal
	return hashVal
}

func (a *ACLToken) Stub() *ACLTokenListStub {
	return &ACLTokenListStub{
		AccessorID:  a.AccessorID,
		Name:        a.Name,
		Type:        a.Type,
		Policies:    a.Policies,
		Global:      a.Global,
		Hash:        a.Hash,
		CreateTime:  a.CreateTime,
		CreateIndex: a.CreateIndex,
		ModifyIndex: a.ModifyIndex,
	}
}

// Validate is used to sanity check a token
func (a *ACLToken) Validate() error {
	var mErr multierror.Error
	if len(a.Name) > maxTokenNameLength {
		mErr.Errors = append(mErr.Errors, fmt.Errorf("token name too long"))
	}
	switch a.Type {
	case ACLClientToken:
		if len(a.Policies) == 0 {
			mErr.Errors = append(mErr.Errors, fmt.Errorf("client token missing policies"))
		}
	case ACLManagementToken:
		if len(a.Policies) != 0 {
			mErr.Errors = append(mErr.Errors, fmt.Errorf("management token cannot be associated with policies"))
		}
	default:
		mErr.Errors = append(mErr.Errors, fmt.Errorf("token type must be client or management"))
	}
	return mErr.ErrorOrNil()
}

// PolicySubset checks if a given set of policies is a subset of the token
func (a *ACLToken) PolicySubset(policies []string) bool {
	// Hot-path the management tokens, superset of all policies.
	if a.Type == ACLManagementToken {
		return true
	}
	associatedPolicies := make(map[string]struct{}, len(a.Policies))
	for _, policy := range a.Policies {
		associatedPolicies[policy] = struct{}{}
	}
	for _, policy := range policies {
		if _, ok := associatedPolicies[policy]; !ok {
			return false
		}
	}
	return true
}

// ACLTokenListRequest is used to request a list of tokens
type ACLTokenListRequest struct {
	GlobalOnly bool
	QueryOptions
}

// ACLTokenSpecificRequest is used to query a specific token
type ACLTokenSpecificRequest struct {
	AccessorID string
	QueryOptions
}

// ACLTokenSetRequest is used to query a set of tokens
type ACLTokenSetRequest struct {
	AccessorIDS []string
	QueryOptions
}

// ACLTokenListResponse is used for a list request
type ACLTokenListResponse struct {
	Tokens []*ACLTokenListStub
	QueryMeta
}

// SingleACLTokenResponse is used to return a single token
type SingleACLTokenResponse struct {
	Token *ACLToken
	QueryMeta
}

// ACLTokenSetResponse is used to return a set of token
type ACLTokenSetResponse struct {
	Tokens map[string]*ACLToken // Keyed by Accessor ID
	QueryMeta
}

// ResolveACLTokenRequest is used to resolve a specific token
type ResolveACLTokenRequest struct {
	SecretID string
	QueryOptions
}

// ResolveACLTokenResponse is used to resolve a single token
type ResolveACLTokenResponse struct {
	Token *ACLToken
	QueryMeta
}

// ACLTokenDeleteRequest is used to delete a set of tokens
type ACLTokenDeleteRequest struct {
	AccessorIDs []string
	WriteRequest
}

// ACLTokenBootstrapRequest is used to bootstrap ACLs
type ACLTokenBootstrapRequest struct {
	Token      *ACLToken // Not client specifiable
	ResetIndex uint64    // Reset index is used to clear the bootstrap token
	WriteRequest
}

// ACLTokenUpsertRequest is used to upsert a set of tokens
type ACLTokenUpsertRequest struct {
	Tokens []*ACLToken
	WriteRequest
}

// ACLTokenUpsertResponse is used to return from an ACLTokenUpsertRequest
type ACLTokenUpsertResponse struct {
	Tokens []*ACLToken
	WriteMeta
}

// RpcError is used for serializing errors with a potential error code
type RpcError struct {
	Message string
	Code    *int64
}

func NewRpcError(err error, code *int64) *RpcError {
	return &RpcError{
		Message: err.Error(),
		Code:    code,
	}
}

func (r *RpcError) Error() string {
	return r.Message
}