fix according to comments

go/master/client.go

@@ -28,6 +28,8 @@ func NewClient(addr Addresser) *Client {
 func (c *Client) monitorMaster(addr Addresser) {
 	lastMaster := ""
 	monitor := func() {
+		// get the lastest address of the master server,
+		// connect to the new address once address changed.
 		curMaster := addr.Address()
 		if curMaster != lastMaster {
 			if curMaster == "" {

go/master/client_test.go

@@ -11,6 +11,8 @@ import (
 	"testing"
 	"time"
 
+	log "github.com/sirupsen/logrus"
+
 	"github.com/PaddlePaddle/Paddle/go/master"
 	"github.com/PaddlePaddle/recordio"
 )
@@ -23,6 +25,8 @@ const (
 var port int
 
 func init() {
+	log.SetLevel(log.ErrorLevel)
+
 	l, err := net.Listen("tcp", ":0")
 	if err != nil {
 		panic(err)
@@ -91,6 +95,17 @@ func TestClientFull(t *testing.T) {
 			t.Fatal(i, "should get error.")
 		}
 
+		err = c.TaskFinished(tasks[0].ID)
+		if err != nil {
+			t.Fatal(err)
+		}
+		tasks = tasks[1:]
+		task, err := c.GetTask()
+		if err != nil {
+			t.Fatal(err)
+		}
+		tasks = append(tasks, task)
+
 		for _, task := range tasks {
 			err = c.TaskFinished(task.ID)
 			if err != nil {

go/master/service.go

@@ -2,12 +2,13 @@ package master
 
 import (
 	"errors"
-	"log"
 	"os"
 	"path/filepath"
 	"sync"
 	"time"
 
+	log "github.com/sirupsen/logrus"
+
 	"github.com/PaddlePaddle/recordio"
 )
 
@@ -112,7 +113,7 @@ func readChunks(globPaths []string) ([]Chunk, error) {
 	}
 
 	if len(paths) == 0 {
-		return nil, errors.New("no valid datset specified")
+		return nil, errors.New("no valid dataset specified")
 	}
 
 	for _, path := range paths {
@@ -170,6 +171,7 @@ func (s *Service) SetDataset(globPaths []string, dummy *int) error {
 
 	err = s.snapshot()
 	if err != nil {
+		log.Errorln(err)
 		return err
 	}
 
@@ -178,6 +180,43 @@ func (s *Service) SetDataset(globPaths []string, dummy *int) error {
 	return nil
 }
 
+func (s *Service) checkTimeoutFunc(taskID int, epoch int) func() {
+	return func() {
+		s.mu.Lock()
+		defer s.mu.Unlock()
+
+		t, ok := s.taskQueues.Pending[taskID]
+		if !ok {
+			return
+		}
+
+		if t.Epoch != epoch {
+			// new epoch, task launched after the
+			// schedule of this timeout check.
+			return
+		}
+
+		defer func() {
+			err := s.snapshot()
+			if err != nil {
+				log.Errorln(err)
+			}
+		}()
+
+		delete(s.taskQueues.Pending, t.Task.ID)
+
+		t.NumTimeout++
+		if t.NumTimeout > s.timeoutMax {
+			log.Warningf("Task %v failed %d times, discard.\n", t.Task, t.NumTimeout)
+			s.taskQueues.Failed = append(s.taskQueues.Failed, t.Task)
+			return
+		}
+
+		log.Warningf("Task %v failed %d times, retry.\n", t.Task, t.NumTimeout)
+		s.taskQueues.Todo = append(s.taskQueues.Todo, t)
+	}
+}
+
 // GetTask gets a new task from the service.
 func (s *Service) GetTask(dummy int, task *Task) error {
 	select {
@@ -190,19 +229,25 @@ func (s *Service) GetTask(dummy int, task *Task) error {
 	if len(s.taskQueues.Todo) == 0 {
 		if len(s.taskQueues.Done) == 0 {
 			if len(s.taskQueues.Pending) == 0 {
-				return errors.New("all task failed")
+				err := errors.New("all task failed")
+				log.Warningln(err)
+				return err
 			}
 
 			// TODO(helin): client need to retry in this
 			// error case. Gotcha: RPC client can't
 			// compare returned error with predefined
-			// errors like io.EOF. Because interface don't
+			// errors like io.EOF, because interface don't
 			// have same dynamic value when in different
-			// process.
-			return errors.New("no more available task")
+			// process. So we need to figure out a way for
+			// client to check this error correctly.
+			err := errors.New("no more available task")
+			log.Warningln(err)
+			return err
 		}
 		s.taskQueues.Todo = s.taskQueues.Done
-		s.taskQueues.Todo = nil
+		s.taskQueues.Done = nil
+		log.Infoln("No more todo task, but trainer is requesting task to do. Move all done task to todo.")
 	}
 
 	t := s.taskQueues.Todo[0]
@@ -215,41 +260,9 @@ func (s *Service) GetTask(dummy int, task *Task) error {
 	}
 
 	*task = t.Task
+	log.Infof("Task #%d dispatched\n", task.ID)
 
-	time.AfterFunc(s.timeoutDur, func(taskID int, epoch int) func() {
-		return func() {
-			s.mu.Lock()
-			defer s.mu.Unlock()
-
-			t, ok := s.taskQueues.Pending[taskID]
-			if !ok {
-				return
-			}
-
-			if t.Epoch != epoch {
-				// new epoch, task launched after the
-				// schedule of this timeout check.
-				return
-			}
-
-			defer func() {
-				err := s.snapshot()
-				if err != nil {
-					log.Println(err)
-				}
-			}()
-
-			delete(s.taskQueues.Pending, t.Task.ID)
-
-			t.NumTimeout++
-			if t.NumTimeout > s.timeoutMax {
-				s.taskQueues.Failed = append(s.taskQueues.Failed, t.Task)
-				return
-			}
-
-			s.taskQueues.Todo = append(s.taskQueues.Todo, t)
-		}
-	}(t.Task.ID, t.Epoch))
+	time.AfterFunc(s.timeoutDur, s.checkTimeoutFunc(t.Task.ID, t.Epoch))
 	return nil
 }
 
@@ -262,9 +275,13 @@ func (s *Service) TaskFinished(taskID int, dummy *int) error {
 	s.mu.Lock()
 	defer s.mu.Unlock()
 
+	log.Infof("Task %d finished\n", taskID)
+
 	t, ok := s.taskQueues.Pending[taskID]
 	if !ok {
-		return errors.New("pending task not found")
+		err := errors.New("pending task not found")
+		log.Warningln(err)
+		return err
 	}
 
 	// task finished, reset timeout
@@ -272,10 +289,15 @@ func (s *Service) TaskFinished(taskID int, dummy *int) error {
 	s.taskQueues.Done = append(s.taskQueues.Done, t)
 	delete(s.taskQueues.Pending, taskID)
 
-	if len(s.taskQueues.Pending) == 0 {
+	if len(s.taskQueues.Pending) == 0 && len(s.taskQueues.Todo) == 0 {
+		log.Infoln("No more todo and pending task, start a new pass.")
 		s.taskQueues.Todo = append(s.taskQueues.Todo, s.taskQueues.Done...)
 		s.taskQueues.Done = nil
 	}
 
-	return s.snapshot()
+	err := s.snapshot()
+	if err != nil {
+		log.Errorln(err)
+	}
+	return err
 }

go/pserver/client.go

@@ -57,7 +57,10 @@ func (c *Client) monitorPservers(l Lister, pserverNum int) {
 		}
 
 		for i := range lastServers {
-			if lastServers[i].Addr != curServers[i].Addr {
+			if lastServers[i].Addr == curServers[i].Addr {
+				continue
+			}
+
 			if curServers[i].Addr == "" {
 				err := c.pservers[i].Close()
 				if err != nil {
@@ -76,7 +79,7 @@ func (c *Client) monitorPservers(l Lister, pserverNum int) {
 				// to retry next time.
 				curServers[i].Addr = lastServers[i].Addr
 			}
-			}
+
 		}
 
 		lastServers = curServers