open-nomad/scheduler/context.go

127 lines
3 KiB
Go

package scheduler
import (
"log"
"regexp"
"github.com/hashicorp/go-version"
"github.com/hashicorp/nomad/nomad/structs"
)
// Context is used to track contextual information used for placement
type Context interface {
// State is used to inspect the current global state
State() State
// Plan returns the current plan
Plan() *structs.Plan
// Logger provides a way to log
Logger() *log.Logger
// Metrics returns the current metrics
Metrics() *structs.AllocMetric
// Reset is invoked after making a placement
Reset()
// ProposedAllocs returns the proposed allocations for a node
// which is the existing allocations, removing evictions, and
// adding any planned placements.
ProposedAllocs(nodeID string) ([]*structs.Allocation, error)
// RegexpCache is a cache of regular expressions
RegexpCache() map[string]*regexp.Regexp
// ConstraintCache is a cache of version constraints
ConstraintCache() map[string]version.Constraints
}
// EvalCache is used to cache certain things during an evaluation
type EvalCache struct {
reCache map[string]*regexp.Regexp
constraintCache map[string]version.Constraints
}
func (e *EvalCache) RegexpCache() map[string]*regexp.Regexp {
if e.reCache == nil {
e.reCache = make(map[string]*regexp.Regexp)
}
return e.reCache
}
func (e *EvalCache) ConstraintCache() map[string]version.Constraints {
if e.constraintCache == nil {
e.constraintCache = make(map[string]version.Constraints)
}
return e.constraintCache
}
// EvalContext is a Context used during an Evaluation
type EvalContext struct {
EvalCache
state State
plan *structs.Plan
logger *log.Logger
metrics *structs.AllocMetric
}
// NewEvalContext constructs a new EvalContext
func NewEvalContext(s State, p *structs.Plan, log *log.Logger) *EvalContext {
ctx := &EvalContext{
state: s,
plan: p,
logger: log,
metrics: new(structs.AllocMetric),
}
return ctx
}
func (e *EvalContext) State() State {
return e.state
}
func (e *EvalContext) Plan() *structs.Plan {
return e.plan
}
func (e *EvalContext) Logger() *log.Logger {
return e.logger
}
func (e *EvalContext) Metrics() *structs.AllocMetric {
return e.metrics
}
func (e *EvalContext) SetState(s State) {
e.state = s
}
func (e *EvalContext) Reset() {
e.metrics = new(structs.AllocMetric)
}
func (e *EvalContext) ProposedAllocs(nodeID string) ([]*structs.Allocation, error) {
// Get the existing allocations
existingAlloc, err := e.state.AllocsByNode(nodeID)
if err != nil {
return nil, err
}
// Filter on alloc state
existingAlloc = structs.FilterTerminalAllocs(existingAlloc)
// Determine the proposed allocation by first removing allocations
// that are planned evictions and adding the new allocations.
proposed := existingAlloc
if update := e.plan.NodeUpdate[nodeID]; len(update) > 0 {
proposed = structs.RemoveAllocs(existingAlloc, update)
}
proposed = append(proposed, e.plan.NodeAllocation[nodeID]...)
// Ensure the return is not nil
if proposed == nil {
proposed = make([]*structs.Allocation, 0)
}
return proposed, nil
}