Remove user-specifiable gc threshold

api/jobs.go

@@ -107,12 +107,6 @@ type UpdateStrategy struct {
 	MaxParallel int
 }
 
-// JobGCConfig configures the garbage collection policy of a job.
-type JobGCConfig struct {
-	Enabled   bool
-	Threshold time.Duration
-}
-
 // Job is used to serialize a job.
 type Job struct {
 	Region            string
@@ -125,7 +119,7 @@ type Job struct {
 	Constraints       []*Constraint
 	TaskGroups        []*TaskGroup
 	Update            *UpdateStrategy
-	GC                *JobGCConfig
+	GC                bool
 	Meta              map[string]string
 	Status            string
 	StatusDescription string

jobspec/parse.go

@@ -723,7 +723,7 @@ func parsePeriodic(result **structs.PeriodicConfig, list *ast.ObjectList) error
 	return nil
 }
 
-func parseGC(result **structs.JobGCConfig, list *ast.ObjectList) error {
+func parseGC(result *bool, list *ast.ObjectList) error {
 	list = list.Elem()
 	if len(list.Items) > 1 {
 		return fmt.Errorf("only one 'gc' block allowed per job")
@@ -738,23 +738,17 @@ func parseGC(result **structs.JobGCConfig, list *ast.ObjectList) error {
 	}
 
 	// Enabled by default if the gc block exists.
+	enabled := false
 	if value, ok := m["enabled"]; !ok {
-		m["Enabled"] = true
+		enabled = true
 	} else {
-		enabled, err := parseBool(value)
+		var err error
+		enabled, err = parseBool(value)
 		if err != nil {
 			return fmt.Errorf("gc.enabled should be set to true or false; %v", err)
 		}
-		m["Enabled"] = enabled
 	}
 
-	dec, err := mapstructure.NewDecoder(&mapstructure.DecoderConfig{
-		DecodeHook:       mapstructure.StringToTimeDurationHookFunc(),
-		WeaklyTypedInput: true,
-		Result:           result,
-	})
-	if err != nil {
-		return err
-	}
-	return dec.Decode(m)
+	*result = enabled
+	return nil
 }

jobspec/parse_test.go

@@ -254,10 +254,7 @@ func TestParse(t *testing.T) {
 				Priority: 50,
 				Region:   "global",
 				Type:     "service",
-				GC: &structs.JobGCConfig{
-					Enabled:   true,
-					Threshold: 2 * time.Hour,
-				},
+				GC:       true,
 			},
 			false,
 		},

jobspec/test-fixtures/gc.hcl

@@ -1,5 +1,5 @@
 job "foo" {
     gc {
-        threshold = "2h"
+        enabled = true
     }
 }

nomad/config.go

@@ -135,6 +135,10 @@ type Config struct {
 	// available for garbage collection.
 	JobGCInterval time.Duration
 
+	// JobGCThreshold is how old a job must be before it eligible for GC. This gives
+	// the user time to inspect the job.
+	JobGCThreshold time.Duration
+
 	// NodeGCInterval is how often we dispatch a job to GC failed nodes.
 	NodeGCInterval time.Duration
 
@@ -207,6 +211,7 @@ func DefaultConfig() *Config {
 		EvalGCInterval:         5 * time.Minute,
 		EvalGCThreshold:        1 * time.Hour,
 		JobGCInterval:          5 * time.Minute,
+		JobGCThreshold:         4 * time.Hour,
 		NodeGCInterval:         5 * time.Minute,
 		NodeGCThreshold:        24 * time.Hour,
 		EvalNackTimeout:        60 * time.Second,

nomad/core_sched.go

@@ -50,6 +50,10 @@ func (c *CoreScheduler) jobGC(eval *structs.Evaluation) error {
 
 	// Get the time table to calculate GC cutoffs.
 	tt := c.srv.fsm.TimeTable()
+	cutoff := time.Now().UTC().Add(-1 * c.srv.config.JobGCThreshold)
+	oldThreshold := tt.NearestIndex(cutoff)
+	c.srv.logger.Printf("[DEBUG] sched.core: job GC: scanning before index %d (%v)",
+		oldThreshold, c.srv.config.JobGCThreshold)
 
 	// Collect the allocations and evaluations to GC
 	var gcAlloc, gcEval, gcJob []string
@@ -57,8 +61,6 @@ func (c *CoreScheduler) jobGC(eval *structs.Evaluation) error {
 OUTER:
 	for i := jIter.Next(); i != nil; i = jIter.Next() {
 		job := i.(*structs.Job)
-		cutoff := time.Now().UTC().Add(-1 * job.GC.Threshold)
-		oldThreshold := tt.NearestIndex(cutoff)
 
 		// Ignore new jobs.
 		if job.CreateIndex > oldThreshold {

nomad/core_sched_test.go

@@ -145,11 +145,7 @@ func TestCoreScheduler_JobGC(t *testing.T) {
 		// Insert job.
 		state := s1.fsm.State()
 		job := mock.Job()
-		threshold := 1 * time.Hour
-		job.GC = &structs.JobGCConfig{
-			Enabled:   true,
-			Threshold: threshold,
-		}
+		job.GC = true
 		err := state.UpsertJob(1000, job)
 		if err != nil {
 			t.Fatalf("test(%s) err: %v", test.test, err)

nomad/state/schema.go

@@ -121,11 +121,7 @@ func jobIsGCable(obj interface{}) (bool, error) {
 		return false, fmt.Errorf("Unexpected type: %v", obj)
 	}
 
-	if j.GC == nil || !j.GC.Enabled {
-		return false, nil
-	}
-
-	return true, nil
+	return j.GC, nil
 }
 
 // evalTableSchema returns the MemDB schema for the eval table.

nomad/state/state_store_test.go

@@ -486,10 +486,7 @@ func TestStateStore_JobsByGC(t *testing.T) {
 
 	for i := 0; i < 10; i++ {
 		job := mock.Job()
-		job.GC = &structs.JobGCConfig{
-			Enabled:   true,
-			Threshold: structs.DefaultJobGCThreshold,
-		}
+		job.GC = true
 		gc = append(gc, job)
 
 		if err := state.UpsertJob(2000+uint64(i), job); err != nil {

nomad/structs/structs.go

@@ -766,7 +766,7 @@ type Job struct {
 
 	// GC is used to mark the job as available for garbage collection after it
 	// has no outstanding evaluations or allocations.
-	GC *JobGCConfig
+	GC bool
 
 	// Meta is used to associate arbitrary metadata with this
 	// job. This is opaque to Nomad.
@@ -788,11 +788,6 @@ type Job struct {
 func (j *Job) InitFields() {
 	// Initialize the service block.
 	j.InitAllServiceFields()
-
-	// Initalize the GC policy
-	if j.GC != nil {
-		j.GC.Init()
-	}
 }
 
 // InitAllServiceFields traverses all Task Groups and makes them
@@ -870,13 +865,6 @@ func (j *Job) Validate() error {
 			fmt.Errorf("Periodic can only be used with %q scheduler", JobTypeBatch))
 	}
 
-	// Validate the GC config.
-	if j.GC != nil {
-		if err := j.GC.Validate(); err != nil {
-			mErr.Errors = append(mErr.Errors, err)
-		}
-	}
-
 	return mErr.ErrorOrNil()
 }
 
@@ -922,37 +910,6 @@ type JobListStub struct {
 	ModifyIndex       uint64
 }
 
-const (
-	// DefaultJobGCThreshold is the default threshold for garbage collecting
-	// eligible jobs.
-	DefaultJobGCThreshold = 4 * time.Hour
-)
-
-// JobGCConfig configures the garbage collection policy of a job.
-type JobGCConfig struct {
-	// Enabled determines whether the job is eligible for garbage collection.
-	Enabled bool
-
-	// Threshold is how old a job must be before it eligible for GC. This gives
-	// the user time to inspect the job.
-	Threshold time.Duration
-}
-
-// Init sets the Threshold time to its default value if it is un-specified but
-// garbage collection is enabled.
-func (gc *JobGCConfig) Init() {
-	if gc.Enabled && gc.Threshold == 0 {
-		gc.Threshold = DefaultJobGCThreshold
-	}
-}
-
-func (gc *JobGCConfig) Validate() error {
-	if gc.Threshold < 0 {
-		return fmt.Errorf("job GC threshold must be positive: %v", gc.Threshold)
-	}
-	return nil
-}
-
 // UpdateStrategy is used to modify how updates are done
 type UpdateStrategy struct {
 	// Stagger is the amount of time between the updates

website/source/docs/jobspec/index.html.md

@@ -156,7 +156,7 @@ The `job` object supports the following keys:
   and "h" suffix can be used, such as "30s". Both values default to zero,
   which disables rolling updates.
 
-*   `gc` - Specifies the job's garbage collection configuration. This allows jobs
+*   `gc` - Toggles the job's eligibility for garbage collection. This allows jobs
     to be garbage collected when all their evaluations and allocations are
     terminal. The `gc` block has the following format:
 
@@ -164,20 +164,14 @@ The `job` object supports the following keys:
     "gc" {
         // Enabled is set to true by default if the "gc" block is included.
         enabled = true
-
-        // Threshold is a duration that configures how old a job must be
-        // before it is garbage collected.
-        threshold = "4h"
     }
+
+    // Equivalent configuration.
+    "gc" {}
     ```
 
     * `enabled`: Toggles the eligibility of a job for garbage collection.
 
-    * `threshold`: `threshold` is a string that should be parseable as a
-      [time.Duration](https://golang.org/pkg/time/#ParseDuration). A job will
-      only be garbage collected after the job, its evaluations and allocations
-      are all older than the threshold.
-
 
 ### Task Group