nomad: Adding Eval model

nomad/schema.go

@@ -18,8 +18,7 @@ func stateStoreSchema() *memdb.DBSchema {
 		indexTableSchema,
 		nodeTableSchema,
 		jobTableSchema,
-		taskGroupTableSchema,
-		taskTableSchema,
+		evalTableSchema,
 		allocTableSchema,
 	}
 
@@ -129,62 +128,31 @@ func jobTableSchema() *memdb.TableSchema {
 	}
 }
 
-// taskGroupTableSchema returns the MemDB schema for the task group table.
-// This table is used to store all the task groups belonging to a job.
-func taskGroupTableSchema() *memdb.TableSchema {
+// evalTableSchema returns the MemDB schema for the eval table.
+// This table is used to store all the evaluations that are pending
+// or recently completed.
+func evalTableSchema() *memdb.TableSchema {
 	return &memdb.TableSchema{
-		Name: "groups",
+		Name: "evals",
 		Indexes: map[string]*memdb.IndexSchema{
-			// Primary index is compount of {Job, Name}
+			// Primary index is used for direct lookup.
 			"id": &memdb.IndexSchema{
 				Name:         "id",
 				AllowMissing: false,
 				Unique:       true,
-				Indexer: &memdb.CompoundIndex{
-					AllowMissing: false,
-					Indexes: []memdb.Indexer{
-						&memdb.StringFieldIndex{
-							Field:     "JobName",
-							Lowercase: true,
-						},
-						&memdb.StringFieldIndex{
-							Field:     "Name",
-							Lowercase: true,
-						},
-					},
+				Indexer: &memdb.UUIDFieldIndex{
+					Field: "ID",
 				},
 			},
-		},
-	}
-}
 
-// taskTableSchema returns the MemDB schema for the tasks table.
-// This table is used to store all the task groups belonging to a job.
-func taskTableSchema() *memdb.TableSchema {
-	return &memdb.TableSchema{
-		Name: "tasks",
-		Indexes: map[string]*memdb.IndexSchema{
-			// Primary index is compount of {Job, TaskGroup, Name}
-			"id": &memdb.IndexSchema{
-				Name:         "id",
+			// Status is used to scan for evaluations that are in need
+			// of scheduling attention.
+			"status": &memdb.IndexSchema{
+				Name:         "status",
 				AllowMissing: false,
-				Unique:       true,
-				Indexer: &memdb.CompoundIndex{
-					AllowMissing: false,
-					Indexes: []memdb.Indexer{
-						&memdb.StringFieldIndex{
-							Field:     "JobName",
-							Lowercase: true,
-						},
-						&memdb.StringFieldIndex{
-							Field:     "TaskGroupName",
-							Lowercase: true,
-						},
-						&memdb.StringFieldIndex{
-							Field:     "Name",
-							Lowercase: true,
-						},
-					},
+				Unique:       false,
+				Indexer: &memdb.StringFieldIndex{
+					Field: "Status",
 				},
 			},
 		},

nomad/state_store_test.go

@@ -100,7 +100,6 @@ func mockJob() *structs.Job {
 					"elb_check_interval": "30s",
 					"elb_check_min":      "3",
 				},
-				Status: structs.JobStatusPending,
 			},
 		},
 		Meta: map[string]string{

nomad/structs/structs.go

@@ -323,9 +323,6 @@ type Job struct {
 // 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 parent job
-	JobID string
-
 	// Name of the task group
 	Name string
 
@@ -343,23 +340,10 @@ type TaskGroup struct {
 	// Meta is used to associate arbitrary metadata with this
 	// task group. This is opaque to Nomad.
 	Meta map[string]string
-
-	// Task group status
-	Status string
-
-	// Raft Indexes
-	CreateIndex uint64
-	ModifyIndex uint64
 }
 
 // Task is a single process typically that is executed as part of a task group.
 type Task struct {
-	// Name of the parent job
-	JobID string
-
-	// Name of the partent task group
-	TaskGroupName string
-
 	// Name of the task
 	Name string
 
@@ -379,10 +363,6 @@ type Task struct {
 	// Meta is used to associate arbitrary metadata with this
 	// task. This is opaque to Nomad.
 	Meta map[string]string
-
-	// Raft Indexes
-	CreateIndex uint64
-	ModifyIndex uint64
 }
 
 // Constraints are used to restrict placement options in the case of
@@ -476,6 +456,30 @@ type AllocMetric struct {
 	AllocationTime time.Duration
 }
 
+const (
+	EvalStatusPending  = "pending"
+	EvalStatusComplete = "complete"
+	EvalStatusCanceled = "canceled"
+)
+
+// 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 {
+	// ID is a randonly generated UUID used for this evaluation. This
+	// is assigned upon the creation of the evaluation.
+	ID string
+
+	// Status of the evaluation
+	Status string
+
+	// Raft Indexes
+	CreateIndex uint64
+	ModifyIndex uint64
+}
+
 // msgpackHandle is a shared handle for encoding/decoding of structs
 var msgpackHandle = &codec.MsgpackHandle{}