fix by helin's comments

go/master/client.go

@@ -62,7 +62,7 @@ func (c *Client) getRecords() {
 		// We treat a task as finished whenever the last data
 		// instance of the task is read. This is not exactly
 		// correct, but a reasonable approximation.
-		c.taskFinished(t.ID)
+		c.taskFinished(t.Meta.ID)
 	}
 }
 
@@ -113,8 +113,8 @@ func (c *Client) taskFinished(taskID int) error {
 }
 
 // TaskFailed tell the master server as task is failed.
-func (c *Client) taskFailed(taskID TaskID) error {
-	return c.conn.Call("Service.TaskFinished", taskID, nil)
+func (c *Client) taskFailed(meta TaskMeta) error {
+	return c.conn.Call("Service.TaskFinished", meta, nil)
 }
 
 // NextRecord returns next record in the dataset.

go/master/client_internal_test.go

@@ -95,7 +95,7 @@ func TestGetFinishTask(t *testing.T) {
 			t.Fatalf("Should get error, pass: %d\n", i)
 		}
 
-		err = c.taskFinished(tasks[0].ID)
+		err = c.taskFinished(tasks[0].Meta.ID)
 		if err != nil {
 			t.Fatalf("Error: %v, pass: %d\n", err, i)
 		}
@@ -107,7 +107,7 @@ func TestGetFinishTask(t *testing.T) {
 		tasks = append(tasks, task)
 
 		for _, task := range tasks {
-			err = c.taskFinished(task.ID)
+			err = c.taskFinished(task.Meta.ID)
 			if err != nil {
 				t.Fatalf("Error: %v, pass: %d\n", err, i)
 			}

go/master/service.go

@@ -31,10 +31,15 @@ type Chunk struct {
 	Index recordio.Index // chunk index
 }
 
+// TaskMeta is a struct which stores task's meta info.
+type TaskMeta struct {
+	ID    int
+	Epoch int
+}
+
 // Task is the basic unit of data instances assigned to trainers.
 type Task struct {
-	ID     int
-	Epoch  int
+	Meta   TaskMeta
 	Chunks []Chunk
 }
 
@@ -74,7 +79,7 @@ func partition(chunks []Chunk, chunksPerTask int) []taskEntry {
 	var cur taskEntry
 	for i, c := range chunks {
 		if i%chunksPerTask == 0 && len(cur.Task.Chunks) > 0 {
-			cur.Task.ID = id
+			cur.Task.Meta.ID = id
 			id++
 			result = append(result, cur)
 			cur.Task.Chunks = nil
@@ -84,7 +89,7 @@ func partition(chunks []Chunk, chunksPerTask int) []taskEntry {
 	}
 
 	if len(cur.Task.Chunks) > 0 {
-		cur.Task.ID = id
+		cur.Task.Meta.ID = id
 		result = append(result, cur)
 	}
 
@@ -258,8 +263,8 @@ func (s *Service) SetDataset(globPaths []string, dummy *int) error {
 	return nil
 }
 
-func (s *Service) procFailedTask(t taskEntry, epoch int) {
-	if t.Task.Epoch != epoch {
+func (s *Service) processFailedTask(t taskEntry, epoch int) {
+	if t.Task.Meta.Epoch != epoch {
 		// new epoch, task launched after the
 		// schedule of this timeout check or failed status report.
 		return
@@ -272,7 +277,7 @@ func (s *Service) procFailedTask(t taskEntry, epoch int) {
 		}
 	}()
 
-	delete(s.taskQueues.Pending, t.Task.ID)
+	delete(s.taskQueues.Pending, t.Task.Meta.ID)
 
 	t.NumFailure++
 	if t.NumFailure > s.failureMax {
@@ -296,7 +301,7 @@ func (s *Service) checkTimeoutFunc(taskID int, epoch int) func() {
 			return
 		}
 
-		s.procFailedTask(t, epoch)
+		s.processFailedTask(t, epoch)
 	}
 }
 
@@ -345,18 +350,18 @@ func (s *Service) GetTask(dummy int, task *Task) error {
 	}
 
 	t := s.taskQueues.Todo[0]
-	t.Task.Epoch++
+	t.Task.Meta.Epoch++
 	s.taskQueues.Todo = s.taskQueues.Todo[1:]
-	s.taskQueues.Pending[t.Task.ID] = t
+	s.taskQueues.Pending[t.Task.Meta.ID] = t
 	err := s.snapshot()
 	if err != nil {
 		return err
 	}
 
 	*task = t.Task
-	log.WithFields(s.logFields()).Infof("Task #%v dispatched.", t)
+	log.WithFields(s.logFields()).Infof("Task #%v dispatched.", t.Meta)
 
-	time.AfterFunc(s.timeoutDur, s.checkTimeoutFunc(t.Task.ID, t.Task.Epoch))
+	time.AfterFunc(s.timeoutDur, s.checkTimeoutFunc(t.Task.Meta.ID, t.Task.Meta.Epoch))
 	return nil
 }
 
@@ -373,7 +378,7 @@ func (s *Service) TaskFinished(taskID int, dummy *int) error {
 	if !ok {
 		err := errors.New("pending task not found")
 		log.WithFields(s.logFields()).Warningln("Pending task #%d not found.", taskID)
-		return err
+		return nil
 	}
 
 	// task finished, reset timeout
@@ -396,14 +401,8 @@ func (s *Service) TaskFinished(taskID int, dummy *int) error {
 	return err
 }
 
-// TaskID is a struct which client uses for reports failure.
-type TaskID struct {
-	ID    int
-	Epoch int
-}
-
 // TaskFailed tells the service that a task is failed.
-func (s *Service) TaskFailed(taskID TaskID, dummy *int) error {
+func (s *Service) TaskFailed(meta TaskMeta, dummy *int) error {
 	select {
 	case <-s.ready:
 	}
@@ -411,13 +410,13 @@ func (s *Service) TaskFailed(taskID TaskID, dummy *int) error {
 	s.mu.Lock()
 	defer s.mu.Unlock()
 
-	t, ok := s.taskQueues.Pending[taskID.ID]
+	t, ok := s.taskQueues.Pending[meta.ID]
 	if !ok {
 		err := errors.New("pending task not found")
-		log.WithFields(s.logFields()).Warningln("TaskFailed:Pending task #%v not found.", taskID)
-		return err
+		log.WithFields(s.logFields()).Warningln("TaskFailed:Pending task #%v not found.", t.Meta)
+		return nil
 	}
 
-	s.procFailedTask(t, taskID.Epoch)
+	s.processFailedTask(t, meta.Epoch)
 	return nil
 }

go/master/service_internal_test.go

@@ -30,7 +30,7 @@ func TestPartionIndex(t *testing.T) {
 	cs := make([]Chunk, 100)
 	ts := partition(cs, 20)
 	for i := range ts {
-		if ts[i].Task.ID != i {
+		if ts[i].Task.Meta.ID != i {
 			t.Error(ts[i], i)
 		}
 	}