open-consul/agent/structs/config_entry_discoverychain.go

1736 lines
52 KiB
Go

package structs
import (
"encoding/json"
"fmt"
"math"
"net/http"
"regexp"
"sort"
"strconv"
"strings"
"time"
"github.com/hashicorp/go-bexpr"
"github.com/mitchellh/copystructure"
"github.com/mitchellh/hashstructure"
"github.com/hashicorp/consul/acl"
"github.com/hashicorp/consul/agent/cache"
"github.com/hashicorp/consul/lib"
)
const (
// Names of Envoy's LB policies
LBPolicyMaglev = "maglev"
LBPolicyRingHash = "ring_hash"
LBPolicyRandom = "random"
LBPolicyLeastRequest = "least_request"
LBPolicyRoundRobin = "round_robin"
// Names of Envoy's LB policies
HashPolicyCookie = "cookie"
HashPolicyHeader = "header"
HashPolicyQueryParam = "query_parameter"
)
var (
validLBPolicies = map[string]bool{
"": true,
LBPolicyRandom: true,
LBPolicyRoundRobin: true,
LBPolicyLeastRequest: true,
LBPolicyRingHash: true,
LBPolicyMaglev: true,
}
validHashPolicies = map[string]bool{
HashPolicyHeader: true,
HashPolicyCookie: true,
HashPolicyQueryParam: true,
}
)
// ServiceRouterConfigEntry defines L7 (e.g. http) routing rules for a named
// service exposed in Connect.
//
// This config entry represents the topmost part of the discovery chain. Only
// one router config will be used per resolved discovery chain and is not
// otherwise discovered recursively (unlike splitter and resolver config
// entries).
//
// Router config entries will be restricted to only services that define their
// protocol as http-based (in centralized configuration).
type ServiceRouterConfigEntry struct {
Kind string
Name string
// Routes is the list of routes to consider when processing L7 requests.
// The first rule to match in the list is terminal and stops further
// evaluation.
//
// Traffic that fails to match any of the provided routes will be routed to
// the default service.
Routes []ServiceRoute
Meta map[string]string `json:",omitempty"`
acl.EnterpriseMeta `hcl:",squash" mapstructure:",squash"`
RaftIndex
}
func (e *ServiceRouterConfigEntry) GetKind() string {
return ServiceRouter
}
func (e *ServiceRouterConfigEntry) GetName() string {
if e == nil {
return ""
}
return e.Name
}
func (e *ServiceRouterConfigEntry) GetMeta() map[string]string {
if e == nil {
return nil
}
return e.Meta
}
func (e *ServiceRouterConfigEntry) Normalize() error {
if e == nil {
return fmt.Errorf("config entry is nil")
}
e.Kind = ServiceRouter
e.EnterpriseMeta.Normalize()
for _, route := range e.Routes {
if route.Match == nil || route.Match.HTTP == nil {
continue
}
httpMatch := route.Match.HTTP
for j := 0; j < len(httpMatch.Methods); j++ {
httpMatch.Methods[j] = strings.ToUpper(httpMatch.Methods[j])
}
if route.Destination != nil && route.Destination.Namespace == "" {
route.Destination.Namespace = e.EnterpriseMeta.NamespaceOrEmpty()
}
if route.Destination != nil && route.Destination.Partition == "" {
route.Destination.Partition = e.EnterpriseMeta.PartitionOrEmpty()
}
}
return nil
}
func (e *ServiceRouterConfigEntry) Validate() error {
if e.Name == "" {
return fmt.Errorf("Name is required")
}
if err := validateConfigEntryMeta(e.Meta); err != nil {
return err
}
// Technically you can have no explicit routes at all where just the
// catch-all is configured for you, but at that point maybe you should just
// delete it so it will default?
for i, route := range e.Routes {
eligibleForPrefixRewrite := false
if route.Match != nil && route.Match.HTTP != nil {
pathParts := 0
if route.Match.HTTP.PathExact != "" {
eligibleForPrefixRewrite = true
pathParts++
if !strings.HasPrefix(route.Match.HTTP.PathExact, "/") {
return fmt.Errorf("Route[%d] PathExact doesn't start with '/': %q", i, route.Match.HTTP.PathExact)
}
}
if route.Match.HTTP.PathPrefix != "" {
eligibleForPrefixRewrite = true
pathParts++
if !strings.HasPrefix(route.Match.HTTP.PathPrefix, "/") {
return fmt.Errorf("Route[%d] PathPrefix doesn't start with '/': %q", i, route.Match.HTTP.PathPrefix)
}
}
if route.Match.HTTP.PathRegex != "" {
pathParts++
}
if pathParts > 1 {
return fmt.Errorf("Route[%d] should only contain at most one of PathExact, PathPrefix, or PathRegex", i)
}
for j, hdr := range route.Match.HTTP.Header {
if hdr.Name == "" {
return fmt.Errorf("Route[%d] Header[%d] missing required Name field", i, j)
}
hdrParts := 0
if hdr.Present {
hdrParts++
}
if hdr.Exact != "" {
hdrParts++
}
if hdr.Regex != "" {
hdrParts++
}
if hdr.Prefix != "" {
hdrParts++
}
if hdr.Suffix != "" {
hdrParts++
}
if hdrParts != 1 {
return fmt.Errorf("Route[%d] Header[%d] should only contain one of Present, Exact, Prefix, Suffix, or Regex", i, j)
}
}
for j, qm := range route.Match.HTTP.QueryParam {
if qm.Name == "" {
return fmt.Errorf("Route[%d] QueryParam[%d] missing required Name field", i, j)
}
qmParts := 0
if qm.Present {
qmParts++
}
if qm.Exact != "" {
qmParts++
}
if qm.Regex != "" {
qmParts++
}
if qmParts != 1 {
return fmt.Errorf("Route[%d] QueryParam[%d] should only contain one of Present, Exact, or Regex", i, j)
}
}
if len(route.Match.HTTP.Methods) > 0 {
found := make(map[string]struct{})
for _, m := range route.Match.HTTP.Methods {
if !isValidHTTPMethod(m) {
return fmt.Errorf("Route[%d] Methods contains an invalid method %q", i, m)
}
if _, ok := found[m]; ok {
return fmt.Errorf("Route[%d] Methods contains %q more than once", i, m)
}
found[m] = struct{}{}
}
}
}
if route.Destination != nil {
if route.Destination.PrefixRewrite != "" && !eligibleForPrefixRewrite {
return fmt.Errorf("Route[%d] cannot make use of PrefixRewrite without configuring either PathExact or PathPrefix", i)
}
for _, r := range route.Destination.RetryOn {
if !isValidRetryCondition(r) {
return fmt.Errorf("Route[%d] contains an invalid retry condition: %q", i, r)
}
}
}
}
return nil
}
func isValidHTTPMethod(method string) bool {
switch method {
case http.MethodGet,
http.MethodHead,
http.MethodPost,
http.MethodPut,
http.MethodPatch,
http.MethodDelete,
http.MethodConnect,
http.MethodOptions,
http.MethodTrace:
return true
default:
return false
}
}
func isValidRetryCondition(retryOn string) bool {
switch retryOn {
case "5xx",
"gateway-error",
"reset",
"connect-failure",
"envoy-ratelimited",
"retriable-4xx",
"refused-stream",
"cancelled",
"deadline-exceeded",
"internal",
"resource-exhausted",
"unavailable":
return true
default:
return false
}
}
func (e *ServiceRouterConfigEntry) CanRead(authz acl.Authorizer) error {
return canReadDiscoveryChain(e, authz)
}
func (e *ServiceRouterConfigEntry) CanWrite(authz acl.Authorizer) error {
return canWriteDiscoveryChain(e, authz)
}
func (e *ServiceRouterConfigEntry) GetRaftIndex() *RaftIndex {
if e == nil {
return &RaftIndex{}
}
return &e.RaftIndex
}
func (e *ServiceRouterConfigEntry) ListRelatedServices() []ServiceID {
found := make(map[ServiceID]struct{})
// We always inject a default catch-all route to the same service as the router.
svcID := NewServiceID(e.Name, &e.EnterpriseMeta)
found[svcID] = struct{}{}
for _, route := range e.Routes {
if route.Destination != nil {
destID := NewServiceID(defaultIfEmpty(route.Destination.Service, e.Name), route.Destination.GetEnterpriseMeta(&e.EnterpriseMeta))
if destID != svcID {
found[destID] = struct{}{}
}
}
}
if len(found) == 0 {
return nil
}
out := make([]ServiceID, 0, len(found))
for svc := range found {
out = append(out, svc)
}
sort.Slice(out, func(i, j int) bool {
return out[i].EnterpriseMeta.LessThan(&out[j].EnterpriseMeta) ||
out[i].ID < out[j].ID
})
return out
}
func (e *ServiceRouterConfigEntry) GetEnterpriseMeta() *acl.EnterpriseMeta {
if e == nil {
return nil
}
return &e.EnterpriseMeta
}
// ServiceRoute is a single routing rule that routes traffic to the destination
// when the match criteria applies.
type ServiceRoute struct {
Match *ServiceRouteMatch `json:",omitempty"`
Destination *ServiceRouteDestination `json:",omitempty"`
}
// ServiceRouteMatch is a set of criteria that can match incoming L7 requests.
type ServiceRouteMatch struct {
HTTP *ServiceRouteHTTPMatch `json:",omitempty"`
// If we have non-http match criteria for other protocols in the future
// (gRPC, redis, etc) they can go here.
}
func (m *ServiceRouteMatch) IsEmpty() bool {
return m.HTTP == nil || m.HTTP.IsEmpty()
}
// ServiceRouteHTTPMatch is a set of http-specific match criteria.
type ServiceRouteHTTPMatch struct {
PathExact string `json:",omitempty" alias:"path_exact"`
PathPrefix string `json:",omitempty" alias:"path_prefix"`
PathRegex string `json:",omitempty" alias:"path_regex"`
Header []ServiceRouteHTTPMatchHeader `json:",omitempty"`
QueryParam []ServiceRouteHTTPMatchQueryParam `json:",omitempty" alias:"query_param"`
Methods []string `json:",omitempty"`
}
func (m *ServiceRouteHTTPMatch) IsEmpty() bool {
return m.PathExact == "" &&
m.PathPrefix == "" &&
m.PathRegex == "" &&
len(m.Header) == 0 &&
len(m.QueryParam) == 0 &&
len(m.Methods) == 0
}
type ServiceRouteHTTPMatchHeader struct {
Name string
Present bool `json:",omitempty"`
Exact string `json:",omitempty"`
Prefix string `json:",omitempty"`
Suffix string `json:",omitempty"`
Regex string `json:",omitempty"`
Invert bool `json:",omitempty"`
}
type ServiceRouteHTTPMatchQueryParam struct {
Name string
Present bool `json:",omitempty"`
Exact string `json:",omitempty"`
Regex string `json:",omitempty"`
}
// ServiceRouteDestination describes how to proxy the actual matching request
// to a service.
type ServiceRouteDestination struct {
// Service is the service to resolve instead of the default service. If
// empty then the default discovery chain service name is used.
Service string `json:",omitempty"`
// ServiceSubset is a named subset of the given service to resolve instead
// of one defined as that service's DefaultSubset. If empty the default
// subset is used.
//
// If this field is specified then this route is ineligible for further
// splitting.
ServiceSubset string `json:",omitempty" alias:"service_subset"`
// Namespace is the namespace to resolve the service from instead of the
// current namespace. If empty the current namespace is assumed.
//
// If this field is specified then this route is ineligible for further
// splitting.
Namespace string `json:",omitempty"`
// Partition is the partition to resolve the service from instead of the
// current partition. If empty the current partition is assumed.
//
// If this field is specified then this route is ineligible for further
// splitting.
Partition string `json:",omitempty"`
// PrefixRewrite allows for the proxied request to have its matching path
// prefix modified before being sent to the destination. Described more
// below in the envoy implementation section.
PrefixRewrite string `json:",omitempty" alias:"prefix_rewrite"`
// RequestTimeout is the total amount of time permitted for the entire
// downstream request (and retries) to be processed.
RequestTimeout time.Duration `json:",omitempty" alias:"request_timeout"`
// IdleTimeout is The total amount of time permitted for the request stream
// to be idle
IdleTimeout time.Duration `json:",omitempty" alias:"idle_timeout"`
// NumRetries is the number of times to retry the request when a retryable
// result occurs. This seems fairly proxy agnostic.
NumRetries uint32 `json:",omitempty" alias:"num_retries"`
// RetryOnConnectFailure allows for connection failure errors to trigger a
// retry. This should be expressible in other proxies as it's just a layer
// 4 failure bubbling up to layer 7.
RetryOnConnectFailure bool `json:",omitempty" alias:"retry_on_connect_failure"`
// RetryOn allows setting envoy specific conditions when a request should
// be automatically retried.
RetryOn []string `json:",omitempty" alias:"retry_on"`
// RetryOnStatusCodes is a flat list of http response status codes that are
// eligible for retry. This again should be feasible in any reasonable proxy.
RetryOnStatusCodes []uint32 `json:",omitempty" alias:"retry_on_status_codes"`
// Allow HTTP header manipulation to be configured.
RequestHeaders *HTTPHeaderModifiers `json:",omitempty" alias:"request_headers"`
ResponseHeaders *HTTPHeaderModifiers `json:",omitempty" alias:"response_headers"`
}
func (e *ServiceRouteDestination) MarshalJSON() ([]byte, error) {
type Alias ServiceRouteDestination
exported := &struct {
RequestTimeout string `json:",omitempty"`
IdleTimeout string `json:",omitempty"`
*Alias
}{
RequestTimeout: e.RequestTimeout.String(),
IdleTimeout: e.IdleTimeout.String(),
Alias: (*Alias)(e),
}
if e.RequestTimeout == 0 {
exported.RequestTimeout = ""
}
if e.IdleTimeout == 0 {
exported.IdleTimeout = ""
}
return json.Marshal(exported)
}
func (e *ServiceRouteDestination) UnmarshalJSON(data []byte) error {
type Alias ServiceRouteDestination
aux := &struct {
RequestTimeout string
IdleTimeout string
*Alias
}{
Alias: (*Alias)(e),
}
if err := lib.UnmarshalJSON(data, &aux); err != nil {
return err
}
var err error
if aux.RequestTimeout != "" {
if e.RequestTimeout, err = time.ParseDuration(aux.RequestTimeout); err != nil {
return err
}
}
if aux.IdleTimeout != "" {
if e.IdleTimeout, err = time.ParseDuration(aux.IdleTimeout); err != nil {
return err
}
}
return nil
}
func (d *ServiceRouteDestination) HasRetryFeatures() bool {
return d.NumRetries > 0 || d.RetryOnConnectFailure || len(d.RetryOnStatusCodes) > 0 || len(d.RetryOn) > 0
}
// ServiceSplitterConfigEntry defines how incoming requests are split across
// different subsets of a single service (like during staged canary rollouts),
// or perhaps across different services (like during a v2 rewrite or other type
// of codebase migration).
//
// This config entry represents the next hop of the discovery chain after
// routing. If no splitter config is defined the chain assumes 100% of traffic
// goes to the default service and discovery continues on to the resolution
// hop.
//
// Splitter configs are recursively collected while walking the discovery
// chain.
//
// Splitter config entries will be restricted to only services that define
// their protocol as http-based (in centralized configuration).
type ServiceSplitterConfigEntry struct {
Kind string
Name string
// Splits is the configurations for the details of the traffic splitting.
//
// The sum of weights across all splits must add up to 100.
//
// If the split is within epsilon of 100 then the remainder is attributed
// to the FIRST split.
Splits []ServiceSplit
Meta map[string]string `json:",omitempty"`
acl.EnterpriseMeta `hcl:",squash" mapstructure:",squash"`
RaftIndex
}
func (e *ServiceSplitterConfigEntry) GetKind() string {
return ServiceSplitter
}
func (e *ServiceSplitterConfigEntry) GetName() string {
if e == nil {
return ""
}
return e.Name
}
func (e *ServiceSplitterConfigEntry) GetMeta() map[string]string {
if e == nil {
return nil
}
return e.Meta
}
func (e *ServiceSplitterConfigEntry) Normalize() error {
if e == nil {
return fmt.Errorf("config entry is nil")
}
e.Kind = ServiceSplitter
// This slightly massages inputs to enforce that the smallest representable
// weight is 1/10000 or .01%
e.EnterpriseMeta.Normalize()
if len(e.Splits) > 0 {
for i, split := range e.Splits {
if split.Namespace == "" {
split.Namespace = e.EnterpriseMeta.NamespaceOrDefault()
}
e.Splits[i].Weight = NormalizeServiceSplitWeight(split.Weight)
}
}
return nil
}
func NormalizeServiceSplitWeight(weight float32) float32 {
weightScaled := scaleWeight(weight)
return float32(weightScaled) / 100.0
}
func (e *ServiceSplitterConfigEntry) Validate() error {
if e.Name == "" {
return fmt.Errorf("Name is required")
}
if len(e.Splits) == 0 {
return fmt.Errorf("no splits configured")
}
if err := validateConfigEntryMeta(e.Meta); err != nil {
return err
}
const maxScaledWeight = 100 * 100
copyAsKey := func(s ServiceSplit) ServiceSplit {
s.Weight = 0
return s
}
// Make sure we didn't refer to the same thing twice.
found := make(map[ServiceSplit]struct{})
for _, split := range e.Splits {
splitKey := copyAsKey(split)
if splitKey.Service == "" {
splitKey.Service = e.Name
}
if _, ok := found[splitKey]; ok {
return fmt.Errorf(
"split destination occurs more than once: service=%q, subset=%q, namespace=%q, partition=%q",
splitKey.Service, splitKey.ServiceSubset, splitKey.Namespace, splitKey.Partition,
)
}
found[splitKey] = struct{}{}
}
sumScaled := 0
for _, split := range e.Splits {
sumScaled += scaleWeight(split.Weight)
}
if sumScaled != maxScaledWeight {
return fmt.Errorf("the sum of all split weights must be 100, not %f", float32(sumScaled)/100)
}
return nil
}
// scaleWeight assumes the input is a value between 0 and 100 representing
// shares out of a percentile range. The function will convert to a unit
// representing 0.01% units in the same manner as you may convert $0.98 to 98
// cents.
func scaleWeight(v float32) int {
return int(math.Round(float64(v * 100.0)))
}
func (e *ServiceSplitterConfigEntry) CanRead(authz acl.Authorizer) error {
return canReadDiscoveryChain(e, authz)
}
func (e *ServiceSplitterConfigEntry) CanWrite(authz acl.Authorizer) error {
return canWriteDiscoveryChain(e, authz)
}
func (e *ServiceSplitterConfigEntry) GetRaftIndex() *RaftIndex {
if e == nil {
return &RaftIndex{}
}
return &e.RaftIndex
}
func (e *ServiceSplitterConfigEntry) GetEnterpriseMeta() *acl.EnterpriseMeta {
if e == nil {
return nil
}
return &e.EnterpriseMeta
}
func (e *ServiceSplitterConfigEntry) ListRelatedServices() []ServiceID {
found := make(map[ServiceID]struct{})
svcID := NewServiceID(e.Name, &e.EnterpriseMeta)
for _, split := range e.Splits {
splitID := NewServiceID(defaultIfEmpty(split.Service, e.Name), split.GetEnterpriseMeta(&e.EnterpriseMeta))
if splitID != svcID {
found[splitID] = struct{}{}
}
}
if len(found) == 0 {
return nil
}
out := make([]ServiceID, 0, len(found))
for svc := range found {
out = append(out, svc)
}
sort.Slice(out, func(i, j int) bool {
return out[i].EnterpriseMeta.LessThan(&out[j].EnterpriseMeta) ||
out[i].ID < out[j].ID
})
return out
}
// ServiceSplit defines how much traffic to send to which set of service
// instances during a traffic split.
type ServiceSplit struct {
// A value between 0 and 100 reflecting what portion of traffic should be
// directed to this split.
//
// The smallest representable weight is 1/10000 or .01%
//
// If the split is within epsilon of 100 then the remainder is attributed
// to the FIRST split.
Weight float32
// Service is the service to resolve instead of the default (optional).
Service string `json:",omitempty"`
// ServiceSubset is a named subset of the given service to resolve instead
// of one defined as that service's DefaultSubset. If empty the default
// subset is used (optional).
//
// If this field is specified then this route is ineligible for further
// splitting.
ServiceSubset string `json:",omitempty" alias:"service_subset"`
// Namespace is the namespace to resolve the service from instead of the
// current namespace. If empty the current namespace is assumed (optional).
//
// If this field is specified then this route is ineligible for further
// splitting.
Namespace string `json:",omitempty"`
// Partition is the partition to resolve the service from instead of the
// current partition. If empty the current partition is assumed (optional).
//
// If this field is specified then this route is ineligible for further
// splitting.
Partition string `json:",omitempty"`
// NOTE: Any configuration added to Splits that needs to be passed to the
// proxy needs special handling MergeParent below.
// Allow HTTP header manipulation to be configured.
RequestHeaders *HTTPHeaderModifiers `json:",omitempty" alias:"request_headers"`
ResponseHeaders *HTTPHeaderModifiers `json:",omitempty" alias:"response_headers"`
}
// MergeParent is called by the discovery chain compiler when a split directs to
// another splitter. We refer to the first ServiceSplit as the parent and the
// ServiceSplits of the second splitter as its children. The parent ends up
// "flattened" by the compiler, i.e. replaced with its children recursively with
// the weights modified as necessary.
//
// Since the parent is never included in the output, any request processing
// config attached to it (e.g. header manipulation) would be lost and not take
// affect when splitters direct to other splitters. To avoid that, we define a
// MergeParent operation which is called by the compiler on each child split
// during flattening. It must merge any request processing configuration from
// the passed parent into the child such that the end result is equivalent to a
// request first passing through the parent and then the child. Response
// handling must occur as if the request first passed through the through the
// child to the parent.
//
// MergeDefaults leaves both s and parent unchanged and returns a deep copy to
// avoid confusing issues where config changes after being compiled.
func (s *ServiceSplit) MergeParent(parent *ServiceSplit) (*ServiceSplit, error) {
if s == nil && parent == nil {
return nil, nil
}
var err error
var copy ServiceSplit
if s == nil {
copy = *parent
copy.RequestHeaders, err = parent.RequestHeaders.Clone()
if err != nil {
return nil, err
}
copy.ResponseHeaders, err = parent.ResponseHeaders.Clone()
if err != nil {
return nil, err
}
return &copy, nil
} else {
copy = *s
}
var parentReq *HTTPHeaderModifiers
if parent != nil {
parentReq = parent.RequestHeaders
}
// Merge any request handling from parent _unless_ it's overridden by us.
copy.RequestHeaders, err = MergeHTTPHeaderModifiers(parentReq, s.RequestHeaders)
if err != nil {
return nil, err
}
var parentResp *HTTPHeaderModifiers
if parent != nil {
parentResp = parent.ResponseHeaders
}
// Merge any response handling. Note that we allow parent to override this
// time since responses flow the other way so the unflattened behavior would
// be that the parent processing happens _after_ ours potentially overriding
// it.
copy.ResponseHeaders, err = MergeHTTPHeaderModifiers(s.ResponseHeaders, parentResp)
if err != nil {
return nil, err
}
return &copy, nil
}
// ServiceResolverConfigEntry defines which instances of a service should
// satisfy discovery requests for a given named service.
//
// This config entry represents the next hop of the discovery chain after
// splitting. If no resolver config is defined the chain assumes 100% of
// traffic goes to the healthy instances of the default service in the current
// datacenter+namespace and discovery terminates.
//
// Resolver configs are recursively collected while walking the chain.
//
// Resolver config entries will be valid for services defined with any protocol
// (in centralized configuration).
type ServiceResolverConfigEntry struct {
Kind string
Name string
// DefaultSubset is the subset to use when no explicit subset is
// requested. If empty the unnamed subset is used.
DefaultSubset string `json:",omitempty" alias:"default_subset"`
// Subsets is a map of subset name to subset definition for all
// usable named subsets of this service. The map key is the name
// of the subset and all names must be valid DNS subdomain elements
// so they can be used in SNI FQDN headers for the Connect Gateways
// feature.
//
// This may be empty, in which case only the unnamed default subset
// will be usable.
Subsets map[string]ServiceResolverSubset `json:",omitempty"`
// Redirect is a service/subset/datacenter/namespace to resolve
// instead of the requested service (optional).
//
// When configured, all occurrences of this resolver in any discovery
// chain evaluation will be substituted for the supplied redirect
// EXCEPT when the redirect has already been applied.
//
// When substituting the supplied redirect into the discovery chain
// all other fields beside Kind/Name/Redirect will be ignored.
Redirect *ServiceResolverRedirect `json:",omitempty"`
// Failover controls when and how to reroute traffic to an alternate pool
// of service instances.
//
// The map is keyed by the service subset it applies to, and the special
// string "*" is a wildcard that applies to any subset not otherwise
// specified here.
Failover map[string]ServiceResolverFailover `json:",omitempty"`
// ConnectTimeout is the timeout for establishing new network connections
// to this service.
ConnectTimeout time.Duration `json:",omitempty" alias:"connect_timeout"`
// LoadBalancer determines the load balancing policy and configuration for services
// issuing requests to this upstream service.
LoadBalancer *LoadBalancer `json:",omitempty" alias:"load_balancer"`
Meta map[string]string `json:",omitempty"`
acl.EnterpriseMeta `hcl:",squash" mapstructure:",squash"`
RaftIndex
}
func (e *ServiceResolverConfigEntry) MarshalJSON() ([]byte, error) {
type Alias ServiceResolverConfigEntry
exported := &struct {
ConnectTimeout string `json:",omitempty"`
*Alias
}{
ConnectTimeout: e.ConnectTimeout.String(),
Alias: (*Alias)(e),
}
if e.ConnectTimeout == 0 {
exported.ConnectTimeout = ""
}
return json.Marshal(exported)
}
func (e *ServiceResolverConfigEntry) UnmarshalJSON(data []byte) error {
type Alias ServiceResolverConfigEntry
aux := &struct {
ConnectTimeout string
*Alias
}{
Alias: (*Alias)(e),
}
if err := lib.UnmarshalJSON(data, &aux); err != nil {
return err
}
var err error
if aux.ConnectTimeout != "" {
if e.ConnectTimeout, err = time.ParseDuration(aux.ConnectTimeout); err != nil {
return err
}
}
return nil
}
func (e *ServiceResolverConfigEntry) SubsetExists(name string) bool {
if name == "" {
return true
}
if len(e.Subsets) == 0 {
return false
}
_, ok := e.Subsets[name]
return ok
}
func (e *ServiceResolverConfigEntry) IsDefault() bool {
return e.DefaultSubset == "" &&
len(e.Subsets) == 0 &&
e.Redirect == nil &&
len(e.Failover) == 0 &&
e.ConnectTimeout == 0 &&
e.LoadBalancer == nil
}
func (e *ServiceResolverConfigEntry) GetKind() string {
return ServiceResolver
}
func (e *ServiceResolverConfigEntry) GetName() string {
if e == nil {
return ""
}
return e.Name
}
func (e *ServiceResolverConfigEntry) GetMeta() map[string]string {
if e == nil {
return nil
}
return e.Meta
}
func (e *ServiceResolverConfigEntry) Normalize() error {
if e == nil {
return fmt.Errorf("config entry is nil")
}
e.Kind = ServiceResolver
e.EnterpriseMeta.Normalize()
return nil
}
func (e *ServiceResolverConfigEntry) Validate() error {
if e.Name == "" {
return fmt.Errorf("Name is required")
}
if err := validateConfigEntryMeta(e.Meta); err != nil {
return err
}
if len(e.Subsets) > 0 {
for name, subset := range e.Subsets {
if name == "" {
return fmt.Errorf("Subset defined with empty name")
}
if err := validateServiceSubset(name); err != nil {
return fmt.Errorf("Subset %q is invalid: %v", name, err)
}
if subset.Filter != "" {
if _, err := bexpr.CreateEvaluator(subset.Filter, nil); err != nil {
return fmt.Errorf("Filter for subset %q is not a valid expression: %v", name, err)
}
}
}
}
isSubset := func(subset string) bool {
if len(e.Subsets) > 0 {
_, ok := e.Subsets[subset]
return ok
}
return false
}
if e.DefaultSubset != "" && !isSubset(e.DefaultSubset) {
return fmt.Errorf("DefaultSubset %q is not a valid subset", e.DefaultSubset)
}
if e.Redirect != nil {
if !e.InDefaultPartition() && e.Redirect.Datacenter != "" {
return fmt.Errorf("Cross-datacenter redirect is only supported in the default partition")
}
if acl.PartitionOrDefault(e.Redirect.Partition) != e.PartitionOrDefault() && e.Redirect.Datacenter != "" {
return fmt.Errorf("Cross-datacenter and cross-partition redirect is not supported")
}
r := e.Redirect
if err := r.ValidateEnterprise(); err != nil {
return fmt.Errorf("Redirect: %s", err.Error())
}
if len(e.Failover) > 0 {
return fmt.Errorf("Redirect and Failover cannot both be set")
}
// TODO(rb): prevent subsets and default subsets from being defined?
if r.isEmpty() {
return fmt.Errorf("Redirect is empty")
}
switch {
case r.Peer != "" && r.ServiceSubset != "":
return fmt.Errorf("Redirect.Peer cannot be set with Redirect.ServiceSubset")
case r.Peer != "" && r.Partition != "":
return fmt.Errorf("Redirect.Partition cannot be set with Redirect.Peer")
case r.Peer != "" && r.Datacenter != "":
return fmt.Errorf("Redirect.Peer cannot be set with Redirect.Datacenter")
case r.Service == "":
if r.ServiceSubset != "" {
return fmt.Errorf("Redirect.ServiceSubset defined without Redirect.Service")
}
if r.Namespace != "" {
return fmt.Errorf("Redirect.Namespace defined without Redirect.Service")
}
if r.Partition != "" {
return fmt.Errorf("Redirect.Partition defined without Redirect.Service")
}
if r.Peer != "" {
return fmt.Errorf("Redirect.Peer defined without Redirect.Service")
}
case r.ServiceSubset != "" && (r.Service == "" || r.Service == e.Name):
if !isSubset(r.ServiceSubset) {
return fmt.Errorf("Redirect.ServiceSubset %q is not a valid subset of %q", r.ServiceSubset, e.Name)
}
}
}
if len(e.Failover) > 0 {
for subset, f := range e.Failover {
if !e.InDefaultPartition() && len(f.Datacenters) != 0 {
return fmt.Errorf("Cross-datacenter failover is only supported in the default partition")
}
errorPrefix := fmt.Sprintf("Bad Failover[%q]: ", subset)
if err := f.ValidateEnterprise(); err != nil {
return fmt.Errorf(errorPrefix + err.Error())
}
if subset != "*" && !isSubset(subset) {
return fmt.Errorf(errorPrefix + "not a valid subset subset")
}
if f.isEmpty() {
return fmt.Errorf(errorPrefix + "one of Service, ServiceSubset, Namespace, Targets, or Datacenters is required")
}
if f.ServiceSubset != "" {
if f.Service == "" || f.Service == e.Name {
if !isSubset(f.ServiceSubset) {
return fmt.Errorf("%sServiceSubset %q is not a valid subset of %q", errorPrefix, f.ServiceSubset, f.Service)
}
}
}
if len(f.Datacenters) != 0 && len(f.Targets) != 0 {
return fmt.Errorf("Bad Failover[%q]: Targets cannot be set with Datacenters", subset)
}
if f.ServiceSubset != "" && len(f.Targets) != 0 {
return fmt.Errorf("Bad Failover[%q]: Targets cannot be set with ServiceSubset", subset)
}
if f.Service != "" && len(f.Targets) != 0 {
return fmt.Errorf("Bad Failover[%q]: Targets cannot be set with Service", subset)
}
for i, target := range f.Targets {
errorPrefix := fmt.Sprintf("Bad Failover[%q].Targets[%d]: ", subset, i)
if err := target.ValidateEnterprise(); err != nil {
return fmt.Errorf(errorPrefix + err.Error())
}
switch {
case target.Peer != "" && target.ServiceSubset != "":
return fmt.Errorf(errorPrefix + "Peer cannot be set with ServiceSubset")
case target.Peer != "" && target.Partition != "":
return fmt.Errorf(errorPrefix + "Partition cannot be set with Peer")
case target.Peer != "" && target.Datacenter != "":
return fmt.Errorf(errorPrefix + "Peer cannot be set with Datacenter")
case target.Partition != "" && target.Datacenter != "":
return fmt.Errorf(errorPrefix + "Partition cannot be set with Datacenter")
case target.ServiceSubset != "" && (target.Service == "" || target.Service == e.Name):
if !isSubset(target.ServiceSubset) {
return fmt.Errorf("%sServiceSubset %q is not a valid subset of %q", errorPrefix, target.ServiceSubset, e.Name)
}
}
}
for _, dc := range f.Datacenters {
if dc == "" {
return fmt.Errorf("Bad Failover[%q].Datacenters: found empty datacenter", subset)
}
}
}
}
if e.ConnectTimeout < 0 {
return fmt.Errorf("Bad ConnectTimeout '%s', must be >= 0", e.ConnectTimeout)
}
if e.LoadBalancer != nil {
lb := e.LoadBalancer
if ok := validLBPolicies[lb.Policy]; !ok {
return fmt.Errorf("Bad LoadBalancer policy: %q is not supported", lb.Policy)
}
if lb.Policy != LBPolicyRingHash && lb.RingHashConfig != nil {
return fmt.Errorf("Bad LoadBalancer configuration. "+
"RingHashConfig specified for incompatible load balancing policy %q", lb.Policy)
}
if lb.Policy != LBPolicyLeastRequest && lb.LeastRequestConfig != nil {
return fmt.Errorf("Bad LoadBalancer configuration. "+
"LeastRequestConfig specified for incompatible load balancing policy %q", lb.Policy)
}
if !lb.IsHashBased() && len(lb.HashPolicies) > 0 {
return fmt.Errorf("Bad LoadBalancer configuration: "+
"HashPolicies specified for non-hash-based Policy: %q", lb.Policy)
}
for i, hp := range lb.HashPolicies {
if ok := validHashPolicies[hp.Field]; hp.Field != "" && !ok {
return fmt.Errorf("Bad LoadBalancer HashPolicy[%d]: %q is not a supported field", i, hp.Field)
}
if hp.SourceIP && hp.Field != "" {
return fmt.Errorf("Bad LoadBalancer HashPolicy[%d]: "+
"A single hash policy cannot hash both a source address and a %q", i, hp.Field)
}
if hp.SourceIP && hp.FieldValue != "" {
return fmt.Errorf("Bad LoadBalancer HashPolicy[%d]: "+
"A FieldValue cannot be specified when hashing SourceIP", i)
}
if hp.Field != "" && hp.FieldValue == "" {
return fmt.Errorf("Bad LoadBalancer HashPolicy[%d]: Field %q was specified without a FieldValue", i, hp.Field)
}
if hp.FieldValue != "" && hp.Field == "" {
return fmt.Errorf("Bad LoadBalancer HashPolicy[%d]: FieldValue requires a Field to apply to", i)
}
if hp.CookieConfig != nil {
if hp.Field != HashPolicyCookie {
return fmt.Errorf("Bad LoadBalancer HashPolicy[%d]: cookie_config provided for %q", i, hp.Field)
}
if hp.CookieConfig.Session && hp.CookieConfig.TTL != 0*time.Second {
return fmt.Errorf("Bad LoadBalancer HashPolicy[%d]: a session cookie cannot have an associated TTL", i)
}
}
}
}
return nil
}
func (e *ServiceResolverConfigEntry) CanRead(authz acl.Authorizer) error {
return canReadDiscoveryChain(e, authz)
}
func (e *ServiceResolverConfigEntry) CanWrite(authz acl.Authorizer) error {
return canWriteDiscoveryChain(e, authz)
}
func (e *ServiceResolverConfigEntry) GetRaftIndex() *RaftIndex {
if e == nil {
return &RaftIndex{}
}
return &e.RaftIndex
}
func (e *ServiceResolverConfigEntry) GetEnterpriseMeta() *acl.EnterpriseMeta {
if e == nil {
return nil
}
return &e.EnterpriseMeta
}
func (e *ServiceResolverConfigEntry) ListRelatedServices() []ServiceID {
found := make(map[ServiceID]struct{})
svcID := NewServiceID(e.Name, &e.EnterpriseMeta)
if e.Redirect != nil {
redirectID := NewServiceID(defaultIfEmpty(e.Redirect.Service, e.Name), e.Redirect.GetEnterpriseMeta(&e.EnterpriseMeta))
if redirectID != svcID {
found[redirectID] = struct{}{}
}
}
if len(e.Failover) > 0 {
for _, failover := range e.Failover {
if len(failover.Targets) == 0 {
failoverID := NewServiceID(defaultIfEmpty(failover.Service, e.Name), failover.GetEnterpriseMeta(&e.EnterpriseMeta))
if failoverID != svcID {
found[failoverID] = struct{}{}
}
continue
}
for _, target := range failover.Targets {
// We can't know about related services on cluster peers.
if target.Peer != "" {
continue
}
failoverID := NewServiceID(defaultIfEmpty(target.Service, e.Name), target.GetEnterpriseMeta(failover.GetEnterpriseMeta(&e.EnterpriseMeta)))
if failoverID != svcID {
found[failoverID] = struct{}{}
}
}
}
}
if len(found) == 0 {
return nil
}
out := make([]ServiceID, 0, len(found))
for svc := range found {
out = append(out, svc)
}
sort.Slice(out, func(i, j int) bool {
return out[i].EnterpriseMeta.LessThan(&out[j].EnterpriseMeta) ||
out[i].ID < out[j].ID
})
return out
}
// ServiceResolverSubset defines a way to select a portion of the Consul
// catalog during service discovery. Anything that affects the ultimate catalog
// query performed OR post-processing on the results of that sort of query
// should be defined here.
type ServiceResolverSubset struct {
// Filter specifies the go-bexpr filter expression to be used for selecting
// instances of the requested service.
Filter string `json:",omitempty"`
// OnlyPassing - Specifies the behavior of the resolver's health check
// filtering. If this is set to false, the results will include instances
// with checks in the passing as well as the warning states. If this is set
// to true, only instances with checks in the passing state will be
// returned. (behaves identically to the similarly named field on prepared
// queries).
OnlyPassing bool `json:",omitempty" alias:"only_passing"`
}
type ServiceResolverRedirect struct {
// Service is a service to resolve instead of the current service
// (optional).
Service string `json:",omitempty"`
// ServiceSubset is a named subset of the given service to resolve instead
// of one defined as that service's DefaultSubset If empty the default
// subset is used (optional).
//
// If this is specified at least one of Service, Datacenter, or Namespace
// should be configured.
ServiceSubset string `json:",omitempty" alias:"service_subset"`
// Namespace is the namespace to resolve the service from instead of the
// current one (optional).
Namespace string `json:",omitempty"`
// Partition is the partition to resolve the service from instead of the
// current one (optional).
Partition string `json:",omitempty"`
// Datacenter is the datacenter to resolve the service from instead of the
// current one (optional).
Datacenter string `json:",omitempty"`
// Peer is the name of the cluster peer to resolve the service from instead
// of the current one (optional).
Peer string `json:",omitempty"`
}
func (r *ServiceResolverRedirect) ToDiscoveryTargetOpts() DiscoveryTargetOpts {
return DiscoveryTargetOpts{
Service: r.Service,
ServiceSubset: r.ServiceSubset,
Namespace: r.Namespace,
Partition: r.Partition,
Datacenter: r.Datacenter,
Peer: r.Peer,
}
}
func (r *ServiceResolverRedirect) isEmpty() bool {
return r.Service == "" && r.ServiceSubset == "" && r.Namespace == "" && r.Partition == "" && r.Datacenter == "" && r.Peer == ""
}
// There are some restrictions on what is allowed in here:
//
// - Service, ServiceSubset, Namespace, Datacenters, and Targets cannot all be
// empty at once. When Targets is defined, the other fields should not be
// populated.
type ServiceResolverFailover struct {
// Service is the service to resolve instead of the default as the failover
// group of instances (optional).
//
// This is a DESTINATION during failover.
Service string `json:",omitempty"`
// ServiceSubset is the named subset of the requested service to resolve as
// the failover group of instances. If empty the default subset for the
// requested service is used (optional).
//
// This is a DESTINATION during failover.
ServiceSubset string `json:",omitempty" alias:"service_subset"`
// Namespace is the namespace to resolve the requested service from to form
// the failover group of instances. If empty the current namespace is used
// (optional).
//
// This is a DESTINATION during failover.
Namespace string `json:",omitempty"`
// Datacenters is a fixed list of datacenters to try. We never try a
// datacenter multiple times, so those are subtracted from this list before
// proceeding.
//
// This is a DESTINATION during failover.
Datacenters []string `json:",omitempty"`
// Targets specifies a fixed list of failover targets to try. We never try a
// target multiple times, so those are subtracted from this list before
// proceeding.
//
// This is a DESTINATION during failover.
Targets []ServiceResolverFailoverTarget `json:",omitempty"`
}
func (t *ServiceResolverFailover) ToDiscoveryTargetOpts() DiscoveryTargetOpts {
return DiscoveryTargetOpts{
Service: t.Service,
ServiceSubset: t.ServiceSubset,
Namespace: t.Namespace,
}
}
func (f *ServiceResolverFailover) isEmpty() bool {
return f.Service == "" && f.ServiceSubset == "" && f.Namespace == "" && len(f.Datacenters) == 0 && len(f.Targets) == 0
}
type ServiceResolverFailoverTarget struct {
// Service specifies the name of the service to try during failover.
Service string `json:",omitempty"`
// ServiceSubset specifies the service subset to try during failover.
ServiceSubset string `json:",omitempty" alias:"service_subset"`
// Partition specifies the partition to try during failover.
Partition string `json:",omitempty"`
// Namespace specifies the namespace to try during failover.
Namespace string `json:",omitempty"`
// Datacenter specifies the datacenter to try during failover.
Datacenter string `json:",omitempty"`
// Peer specifies the name of the cluster peer to try during failover.
Peer string `json:",omitempty"`
}
func (t *ServiceResolverFailoverTarget) ToDiscoveryTargetOpts() DiscoveryTargetOpts {
return DiscoveryTargetOpts{
Service: t.Service,
ServiceSubset: t.ServiceSubset,
Namespace: t.Namespace,
Partition: t.Partition,
Datacenter: t.Datacenter,
Peer: t.Peer,
}
}
// LoadBalancer determines the load balancing policy and configuration for services
// issuing requests to this upstream service.
type LoadBalancer struct {
// Policy is the load balancing policy used to select a host
Policy string `json:",omitempty"`
// RingHashConfig contains configuration for the "ring_hash" policy type
RingHashConfig *RingHashConfig `json:",omitempty" alias:"ring_hash_config"`
// LeastRequestConfig contains configuration for the "least_request" policy type
LeastRequestConfig *LeastRequestConfig `json:",omitempty" alias:"least_request_config"`
// HashPolicies is a list of hash policies to use for hashing load balancing algorithms.
// Hash policies are evaluated individually and combined such that identical lists
// result in the same hash.
// If no hash policies are present, or none are successfully evaluated,
// then a random backend host will be selected.
HashPolicies []HashPolicy `json:",omitempty" alias:"hash_policies"`
}
// RingHashConfig contains configuration for the "ring_hash" policy type
type RingHashConfig struct {
// MinimumRingSize determines the minimum number of entries in the hash ring
MinimumRingSize uint64 `json:",omitempty" alias:"minimum_ring_size"`
// MaximumRingSize determines the maximum number of entries in the hash ring
MaximumRingSize uint64 `json:",omitempty" alias:"maximum_ring_size"`
}
// LeastRequestConfig contains configuration for the "least_request" policy type
type LeastRequestConfig struct {
// ChoiceCount determines the number of random healthy hosts from which to select the one with the least requests.
ChoiceCount uint32 `json:",omitempty" alias:"choice_count"`
}
// HashPolicy defines which attributes will be hashed by hash-based LB algorithms
type HashPolicy struct {
// Field is the attribute type to hash on.
// Must be one of "header","cookie", or "query_parameter".
// Cannot be specified along with SourceIP.
Field string `json:",omitempty"`
// FieldValue is the value to hash.
// ie. header name, cookie name, URL query parameter name
// Cannot be specified along with SourceIP.
FieldValue string `json:",omitempty" alias:"field_value"`
// CookieConfig contains configuration for the "cookie" hash policy type.
CookieConfig *CookieConfig `json:",omitempty" alias:"cookie_config"`
// SourceIP determines whether the hash should be of the source IP rather than of a field and field value.
// Cannot be specified along with Field or FieldValue.
SourceIP bool `json:",omitempty" alias:"source_ip"`
// Terminal will short circuit the computation of the hash when multiple hash policies are present.
// If a hash is computed when a Terminal policy is evaluated,
// then that hash will be used and subsequent hash policies will be ignored.
Terminal bool `json:",omitempty"`
}
// CookieConfig contains configuration for the "cookie" hash policy type.
// This is specified to have Envoy generate a cookie for a client on its first request.
type CookieConfig struct {
// Generates a session cookie with no expiration.
Session bool `json:",omitempty"`
// TTL for generated cookies. Cannot be specified for session cookies.
TTL time.Duration `json:",omitempty"`
// The path to set for the cookie
Path string `json:",omitempty"`
}
func (lb *LoadBalancer) IsHashBased() bool {
if lb == nil {
return false
}
switch lb.Policy {
case LBPolicyMaglev, LBPolicyRingHash:
return true
default:
return false
}
}
type discoveryChainConfigEntry interface {
ConfigEntry
// ListRelatedServices returns a list of other names of services referenced
// in this config entry.
ListRelatedServices() []ServiceID
}
func canReadDiscoveryChain(entry discoveryChainConfigEntry, authz acl.Authorizer) error {
var authzContext acl.AuthorizerContext
entry.GetEnterpriseMeta().FillAuthzContext(&authzContext)
return authz.ToAllowAuthorizer().ServiceReadAllowed(entry.GetName(), &authzContext)
}
func canWriteDiscoveryChain(entry discoveryChainConfigEntry, authz acl.Authorizer) error {
entryID := NewServiceID(entry.GetName(), entry.GetEnterpriseMeta())
var authzContext acl.AuthorizerContext
entryID.FillAuthzContext(&authzContext)
name := entry.GetName()
if err := authz.ToAllowAuthorizer().ServiceWriteAllowed(name, &authzContext); err != nil {
return err
}
for _, svc := range entry.ListRelatedServices() {
if entryID == svc {
continue
}
svc.FillAuthzContext(&authzContext)
// You only need read on related services to redirect traffic flow for
// your own service.
if err := authz.ToAllowAuthorizer().ServiceReadAllowed(svc.ID, &authzContext); err != nil {
return err
}
}
return nil
}
// DiscoveryChainRequest is used when requesting the discovery chain for a
// service.
type DiscoveryChainRequest struct {
Name string
EvaluateInDatacenter string
EvaluateInNamespace string
EvaluateInPartition string
// OverrideMeshGateway allows for the mesh gateway setting to be overridden
// for any resolver in the compiled chain.
OverrideMeshGateway MeshGatewayConfig
// OverrideProtocol allows for the final protocol for the chain to be
// altered.
//
// - If the chain ordinarily would be TCP and an L7 protocol is passed here
// the chain will not include Routers or Splitters.
//
// - If the chain ordinarily would be L7 and TCP is passed here the chain
// will not include Routers or Splitters.
OverrideProtocol string
// OverrideConnectTimeout allows for the ConnectTimeout setting to be
// overridden for any resolver in the compiled chain.
OverrideConnectTimeout time.Duration
Datacenter string // where to route the RPC
QueryOptions
}
func (r *DiscoveryChainRequest) RequestDatacenter() string {
return r.Datacenter
}
func (r *DiscoveryChainRequest) CacheInfo() cache.RequestInfo {
info := cache.RequestInfo{
Token: r.Token,
Datacenter: r.Datacenter,
MinIndex: r.MinQueryIndex,
Timeout: r.MaxQueryTime,
MaxAge: r.MaxAge,
MustRevalidate: r.MustRevalidate,
}
v, err := hashstructure.Hash(struct {
Name string
EvaluateInDatacenter string
EvaluateInNamespace string
EvaluateInPartition string
OverrideMeshGateway MeshGatewayConfig
OverrideProtocol string
OverrideConnectTimeout time.Duration
Filter string
}{
Name: r.Name,
EvaluateInDatacenter: r.EvaluateInDatacenter,
EvaluateInNamespace: r.EvaluateInNamespace,
EvaluateInPartition: r.EvaluateInPartition,
OverrideMeshGateway: r.OverrideMeshGateway,
OverrideProtocol: r.OverrideProtocol,
OverrideConnectTimeout: r.OverrideConnectTimeout,
Filter: r.QueryOptions.Filter,
}, nil)
if err == nil {
// If there is an error, we don't set the key. A blank key forces
// no cache for this request so the request is forwarded directly
// to the server.
info.Key = strconv.FormatUint(v, 10)
}
return info
}
type DiscoveryChainResponse struct {
Chain *CompiledDiscoveryChain
QueryMeta
}
type ConfigEntryGraphError struct {
// one of Message or Err should be set
Message string
Err error
}
func (e *ConfigEntryGraphError) Error() string {
if e.Err != nil {
return e.Err.Error()
}
return e.Message
}
var (
validServiceSubset = regexp.MustCompile(`^[a-z0-9]([a-z0-9-]*[a-z0-9])?$`)
serviceSubsetMaxLength = 63
)
// validateServiceSubset checks if the provided name can be used as an service
// subset. Because these are used in SNI headers they must a DNS label per
// RFC-1035/RFC-1123.
func validateServiceSubset(subset string) error {
if subset == "" || len(subset) > serviceSubsetMaxLength {
return fmt.Errorf("must be non-empty and 63 characters or fewer")
}
if !validServiceSubset.MatchString(subset) {
return fmt.Errorf("must be 63 characters or fewer, begin or end with lower case alphanumeric characters, and contain lower case alphanumeric characters or '-' in between")
}
return nil
}
func defaultIfEmpty(val, defaultVal string) string {
if val != "" {
return val
}
return defaultVal
}
func IsProtocolHTTPLike(protocol string) bool {
switch protocol {
case "http", "http2", "grpc":
return true
default:
return false
}
}
// HTTPHeaderModifiers is a set of rules for HTTP header modification that
// should be performed by proxies as the request passes through them. It can
// operate on either request or response headers depending on the context in
// which it is used.
type HTTPHeaderModifiers struct {
// Add is a set of name -> value pairs that should be appended to the request
// or response (i.e. allowing duplicates if the same header already exists).
Add map[string]string `json:",omitempty"`
// Set is a set of name -> value pairs that should be added to the request or
// response, overwriting any existing header values of the same name.
Set map[string]string `json:",omitempty"`
// Remove is the set of header names that should be stripped from the request
// or response.
Remove []string `json:",omitempty"`
}
func (m *HTTPHeaderModifiers) IsZero() bool {
if m == nil {
return true
}
return len(m.Add) == 0 && len(m.Set) == 0 && len(m.Remove) == 0
}
func (m *HTTPHeaderModifiers) Validate(protocol string) error {
if m.IsZero() {
return nil
}
if !IsProtocolHTTPLike(protocol) {
// Non nil but context is not an httpish protocol
return fmt.Errorf("only valid for http, http2 and grpc protocols")
}
return nil
}
// Clone returns a deep-copy of m unless m is nil
func (m *HTTPHeaderModifiers) Clone() (*HTTPHeaderModifiers, error) {
if m == nil {
return nil, nil
}
cpy, err := copystructure.Copy(m)
if err != nil {
return nil, err
}
m = cpy.(*HTTPHeaderModifiers)
return m, nil
}
// MergeHTTPHeaderModifiers takes a base HTTPHeaderModifiers and merges in field
// defined in overrides. Precedence is given to the overrides field if there is
// a collision. The resulting object is returned leaving both base and overrides
// unchanged. The `Add` field in override also replaces same-named keys of base
// since we have no way to express multiple adds to the same key. We could
// change that, but it makes the config syntax more complex for a huge edgecase.
func MergeHTTPHeaderModifiers(base, overrides *HTTPHeaderModifiers) (*HTTPHeaderModifiers, error) {
if base.IsZero() {
return overrides.Clone()
}
merged, err := base.Clone()
if err != nil {
return nil, err
}
if overrides.IsZero() {
return merged, nil
}
for k, v := range overrides.Add {
merged.Add[k] = v
}
for k, v := range overrides.Set {
merged.Set[k] = v
}
// Deduplicate removes.
removed := make(map[string]struct{})
for _, k := range merged.Remove {
removed[k] = struct{}{}
}
for _, k := range overrides.Remove {
if _, ok := removed[k]; !ok {
merged.Remove = append(merged.Remove, k)
}
}
return merged, nil
}