implement master server client, remove unnecessary dummy variable

go/cmd/master/master.go

 package main
 
 import (
-	"fmt"
 	"net"
 	"net/http"
 	"net/rpc"
-	"os"
-	"path/filepath"
 	"strconv"
-	"strings"
 	"time"
 
 	"github.com/namsral/flag"
 
 	"github.com/PaddlePaddle/Paddle/go/master"
-	"github.com/PaddlePaddle/recordio"
 )
 
 func main() {
 	port := flag.Int("port", 8080, "port of the master server.")
-	dataset := flag.String("training_dataset", "", "dataset: comma separated path to RecordIO paths, supports golb patterns.")
+
 	faultTolerance := flag.Bool("fault_tolerance", false, "enable fault tolerance (requires etcd).")
 	taskTimeoutDur := flag.Duration("task_timout_dur", 20*time.Minute, "task timout duration.")
 	taskTimeoutMax := flag.Int("task_timeout_max", 3, "max timtout count for each task before it being declared failed task.")
 	chunkPerTask := flag.Int("chunk_per_task", 10, "chunk per task.")
 	flag.Parse()
 
-	if *dataset == "" {
-		panic("no dataset specified.")
-	}
-
 	if *faultTolerance {
 		panic("fault tolernance not implemented.")
-	}
-
-	var chunks []master.Chunk
-	var paths []string
-	ss := strings.Split(*dataset, ",")
-	fmt.Println(ss)
-	for _, s := range ss {
-		match, err := filepath.Glob(s)
-		if err != nil {
-			panic(err)
-		}
-		paths = append(paths, match...)
-	}
-
-	if len(paths) == 0 {
-		panic("no valid datset specified.")
-	}
-
-	for _, path := range paths {
-		f, err := os.Open(path)
-		if err != nil {
-			panic(err)
-		}
-
-		index, err := recordio.LoadIndex(f)
-		if err != nil {
-			panic(err)
-		}
-		f.Close()
 
-		count := index.NumChunks()
-		for i := 0; i < count; i++ {
-			chunk := master.Chunk{
-				Path:  path,
-				Index: *index.ChunkIndex(i),
-			}
-			chunks = append(chunks, chunk)
-		}
 	}
 
-	s := master.NewService(chunks, *chunkPerTask, *taskTimeoutDur, *taskTimeoutMax)
+	s := master.NewService(*chunkPerTask, *taskTimeoutDur, *taskTimeoutMax)
 	err := rpc.Register(s)
 	if err != nil {
 		panic(err)

go/master/client.go

@@ -59,16 +59,22 @@ func (c *Client) monitorMaster(addr Addresser) {
 	}
 }
 
+// SetDataset set dataset for the master server to dispatch.
+//
+// SetDataset can be call multiple times from different nodes. But
+// only the first call will be honored.
+func (c *Client) SetDataset(globPaths []string) error {
+	return c.conn.Call("Service.SetDataset", globPaths, nil)
+}
+
 // GetTask gets a new task from the master server.
 func (c *Client) GetTask() (Task, error) {
-	var dummy int
 	var t Task
-	err := c.conn.Call("Service.GetTask", dummy, &t)
+	err := c.conn.Call("Service.GetTask", 0, &t)
 	return t, err
 }
 
 // TaskFinished tells the master server a task is finished.
 func (c *Client) TaskFinished(taskID int) error {
-	var dummy int
-	return c.conn.Call("Service.TaskFinished", taskID, &dummy)
+	return c.conn.Call("Service.TaskFinished", taskID, nil)
 }

go/master/client_test.go

@@ -5,12 +5,14 @@ import (
 	"net"
 	"net/http"
 	"net/rpc"
+	"os"
 	"strconv"
 	"strings"
 	"testing"
 	"time"
 
 	"github.com/PaddlePaddle/Paddle/go/master"
+	"github.com/PaddlePaddle/recordio"
 )
 
 const (
@@ -34,8 +36,7 @@ func init() {
 	port = p
 
 	go func(l net.Listener) {
-		chunks := make([]master.Chunk, totalTask)
-		s := master.NewService(chunks, chunkPerTask, time.Second, 1)
+		s := master.NewService(chunkPerTask, time.Second, 1)
 		server := rpc.NewServer()
 		err := server.Register(s)
 		if err != nil {
@@ -58,21 +59,47 @@ func (a addresser) Address() string {
 }
 
 func TestClientFull(t *testing.T) {
+	const p = "/tmp/master_client_test_0"
+	f, err := os.Create(p)
+	if err != nil {
+		panic(err)
+	}
+
+	for i := 0; i < totalTask*chunkPerTask; i++ {
+		w := recordio.NewWriter(f, -1, -1)
+		w.Write(nil)
+		// call Close to force RecordIO writing a chunk.
+		w.Close()
+	}
+	f.Close()
+
 	c := master.NewClient(addresser(fmt.Sprintf(":%d", port)))
+	c.SetDataset([]string{p})
 
-	for i := 0; i < 5*totalTask/chunkPerTask; i++ {
-		task, err := c.GetTask()
-		if err != nil {
-			panic(err)
+	checkOnePass := func(i int) {
+		var tasks []master.Task
+		for i := 0; i < totalTask; i++ {
+			task, err := c.GetTask()
+			if err != nil {
+				t.Fatal(i, err)
+			}
+			tasks = append(tasks, task)
 		}
 
-		if len(task.Chunks) != chunkPerTask {
-			t.Fatal("wrong number of chunk per task", len(task.Chunks))
+		_, err = c.GetTask()
+		if err == nil {
+			t.Fatal(i, "should get error.")
 		}
 
-		err = c.TaskFinished(task.ID)
-		if err != nil {
-			panic(err)
+		for _, task := range tasks {
+			err = c.TaskFinished(task.ID)
+			if err != nil {
+				t.Fatal(i, err)
+			}
 		}
 	}
+
+	for i := 0; i < 10; i++ {
+		checkOnePass(i)
+	}
 }

go/master/service.go

@@ -3,6 +3,8 @@ package master
 import (
 	"errors"
 	"log"
+	"os"
+	"path/filepath"
 	"sync"
 	"time"
 
@@ -13,18 +15,15 @@ const (
 	targetTaskCount = 300
 )
 
-// errors
-var (
-	ErrNoMoreTask          = errors.New("no more task for current pass")
-	ErrPendingTaskNotFound = errors.New("pending task not found")
-)
-
 // Service is the master server service.
 type Service struct {
-	timeoutDur time.Duration
-	timeoutMax int
+	chunksPerTask int
+	timeoutDur    time.Duration
+	timeoutMax    int
+	ready         chan struct{}
 
 	mu         sync.Mutex
+	initBegan  bool
 	taskQueues taskQueues
 }
 
@@ -63,13 +62,14 @@ func partition(chunks []Chunk, chunksPerTask int) []taskEntry {
 }
 
 // NewService creates a new service.
-func NewService(chunks []Chunk, chunksPerTask int, timeoutDur time.Duration, timeoutMax int) *Service {
+func NewService(chunksPerTask int, timeoutDur time.Duration, timeoutMax int) *Service {
 	s := &Service{}
+	s.chunksPerTask = chunksPerTask
 	s.timeoutDur = timeoutDur
 	s.timeoutMax = timeoutMax
 	s.taskQueues = taskQueues{}
 	s.taskQueues.Pending = make(map[int]taskEntry)
-	s.taskQueues.Todo = partition(chunks, chunksPerTask)
+	s.ready = make(chan struct{})
 	return s
 }
 
@@ -104,13 +104,102 @@ func (s *Service) snapshot() error {
 	return nil
 }
 
+// SetDataset sets dataset to dispatch for the master server.
+//
+// SetDataset can be call multiple times. But only the first call will
+// be honored.
+func (s *Service) SetDataset(globPaths []string, dummy *int) error {
+	if len(globPaths) == 0 {
+		return errors.New("no dataset specified")
+	}
+
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	if s.initBegan {
+		// SetDataset already called. All trainer will call
+		// SetDataset, but we only handle the first one. Treat
+		// other calls as successful but do nothing.
+		return nil
+	}
+
+	s.initBegan = true
+
+	var chunks []Chunk
+	var paths []string
+
+	for _, s := range globPaths {
+		match, err := filepath.Glob(s)
+		if err != nil {
+			panic(err)
+		}
+		paths = append(paths, match...)
+	}
+
+	if len(paths) == 0 {
+		return errors.New("no valid datset specified")
+	}
+
+	for _, path := range paths {
+		f, err := os.Open(path)
+		if err != nil {
+			panic(err)
+		}
+
+		index, err := recordio.LoadIndex(f)
+		if err != nil {
+			return err
+		}
+		err = f.Close()
+		if err != nil {
+			return err
+		}
+
+		count := index.NumChunks()
+		for i := 0; i < count; i++ {
+			chunk := Chunk{
+				Path:  path,
+				Index: *index.ChunkIndex(i),
+			}
+			chunks = append(chunks, chunk)
+		}
+	}
+
+	s.taskQueues.Todo = partition(chunks, s.chunksPerTask)
+
+	err := s.snapshot()
+	if err != nil {
+		return err
+	}
+
+	close(s.ready)
+	return nil
+}
+
 // GetTask gets a new task from the service.
 func (s *Service) GetTask(dummy int, task *Task) error {
+	select {
+	case <-s.ready:
+	}
+
 	s.mu.Lock()
 	defer s.mu.Unlock()
 
 	if len(s.taskQueues.Todo) == 0 {
-		return ErrNoMoreTask
+		if len(s.taskQueues.Done) == 0 {
+			if len(s.taskQueues.Pending) == 0 {
+				return errors.New("all task failed")
+			}
+
+			// TODO(helin): client need to retry in this
+			// error case. Gotcha: RPC client can't
+			// compare returned error with predefined
+			// erros like io.EOF. Because interface don't
+			// have same dynamic value when in different
+			// process.
+			return errors.New("no more available task")
+		}
+		s.taskQueues.Todo = s.taskQueues.Done
+		s.taskQueues.Todo = nil
 	}
 
 	t := s.taskQueues.Todo[0]
@@ -163,12 +252,16 @@ func (s *Service) GetTask(dummy int, task *Task) error {
 
 // TaskFinished tell the service that a task is finished.
 func (s *Service) TaskFinished(taskID int, dummy *int) error {
+	select {
+	case <-s.ready:
+	}
+
 	s.mu.Lock()
 	defer s.mu.Unlock()
 
 	t, ok := s.taskQueues.Pending[taskID]
 	if !ok {
-		return ErrPendingTaskNotFound
+		return errors.New("pending task not found")
 	}
 
 	// task finished, reset timeout
@@ -176,8 +269,8 @@ 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.Todo) == 0 {
-		s.taskQueues.Todo = s.taskQueues.Done
+	if len(s.taskQueues.Pending) == 0 {
+		s.taskQueues.Todo = append(s.taskQueues.Todo, s.taskQueues.Done...)
 		s.taskQueues.Done = nil
 	}
 

go/pserver/client.go

@@ -102,16 +102,14 @@ func (c *Client) BeginInitParams() bool {
 
 // InitParam initializes the parameter on parameter servers.
 func (c *Client) InitParam(paramWithConfigs ParameterWithConfig) error {
-	var dummy int
-	return c.pservers[c.partition(paramWithConfigs.Param.Name)].Call("Service.InitParam", paramWithConfigs, &dummy)
+	return c.pservers[c.partition(paramWithConfigs.Param.Name)].Call("Service.InitParam", paramWithConfigs, nil)
 }
 
 // FinishInitParams tells parameter servers client has sent all
 // parameters to parameter servers as initialization.
 func (c *Client) FinishInitParams() error {
 	for _, p := range c.pservers {
-		var dummy int
-		err := p.Call("Service.FinishInitParams", dummy, &dummy)
+		err := p.Call("Service.FinishInitParams", 0, nil)
 		if err != nil {
 			return err
 		}
@@ -125,8 +123,7 @@ func (c *Client) SendGrads(grads []Gradient) error {
 	errCh := make(chan error, len(grads))
 	for _, g := range grads {
 		go func(g Gradient) {
-			var dummy int
-			err := c.pservers[c.partition(g.Name)].Call("Service.SendGrad", g, &dummy)
+			err := c.pservers[c.partition(g.Name)].Call("Service.SendGrad", g, nil)
 			errCh <- err
 		}(g)
 	}
@@ -205,8 +202,7 @@ func (c *Client) Save(path string) error {
 	errCh := make(chan error, len(c.pservers))
 
 	for _, p := range c.pservers {
-		var dummy int
-		err := p.Call("Service.Save", path, &dummy)
+		err := p.Call("Service.Save", path, nil)
 		errCh <- err
 	}
 

go/pserver/service_test.go

@@ -15,8 +15,7 @@ func TestFull(t *testing.T) {
 	p.Name = "param_a"
 	p.Content = []byte{1, 0, 0, 0, 2, 0, 0, 0, 3, 0, 0, 0}
 	p.ElementType = pserver.Int32
-	var dummy int
-	err := s.InitParam(pserver.ParameterWithConfig{Param: p, Config: nil}, &dummy)
+	err := s.InitParam(pserver.ParameterWithConfig{p, nil}, nil)
 	if err != nil {
 		t.FailNow()
 	}
@@ -25,12 +24,12 @@ func TestFull(t *testing.T) {
 	p1.Name = "param_b"
 	p1.Content = []byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}
 	p1.ElementType = pserver.Float32
-	err = s.InitParam(pserver.ParameterWithConfig{Param: p1, Config: nil}, &dummy)
+	err = s.InitParam(pserver.ParameterWithConfig{p1, nil}, nil)
 	if err != nil {
 		t.FailNow()
 	}
 
-	err = s.FinishInitParams(0, &dummy)
+	err = s.FinishInitParams(0, nil)
 	if err != nil {
 		t.FailNow()
 	}
@@ -46,11 +45,11 @@ func TestFull(t *testing.T) {
 	}
 
 	g1, g2 := pserver.Gradient(p1), pserver.Gradient(p)
-	err = s.SendGrad(g1, &dummy)
+	err = s.SendGrad(g1, nil)
 	if err != nil {
 		t.FailNow()
 	}
-	err = s.SendGrad(g2, &dummy)
+	err = s.SendGrad(g2, nil)
 
 	if err != nil {
 		t.FailNow()
@@ -74,23 +73,21 @@ func TestFull(t *testing.T) {
 
 func TestMultipleInit(t *testing.T) {
 	s := pserver.NewService()
-	var dummy int
-	err := s.FinishInitParams(0, &dummy)
+	err := s.FinishInitParams(0, nil)
 	if err != nil {
 		t.FailNow()
 	}
 
-	err = s.FinishInitParams(0, &dummy)
-	if err.Error() != pserver.AlreadyInitialized {
+	err = s.FinishInitParams(0, nil)
+	if err != pserver.ErrAlreadyInitialized {
 		t.FailNow()
 	}
 }
 
 func TestUninitialized(t *testing.T) {
 	s := pserver.NewService()
-	var dummy int
-	err := s.SendGrad(pserver.Gradient{}, &dummy)
-	if err.Error() != pserver.Uninitialized {
+	err := s.SendGrad(pserver.Gradient{}, nil)
+	if err != pserver.ErrUninitialized {
 		t.FailNow()
 	}
 }
@@ -112,8 +109,7 @@ func TestBlockUntilInitialized(t *testing.T) {
 
 	wg.Add(1)
 	go func() {
-		var dummy int
-		err := s.Save("", &dummy)
+		err := s.Save("", nil)
 		if err != nil {
 			t.FailNow()
 		}
@@ -134,13 +130,12 @@ func TestBlockUntilInitialized(t *testing.T) {
 	p.Name = "param_a"
 	p.Content = []byte{1, 0, 0, 0, 2, 0, 0, 0, 3, 0, 0, 0}
 	p.ElementType = pserver.Int32
-	var dummy int
-	err := s.InitParam(pserver.ParameterWithConfig{Param: p, Config: nil}, &dummy)
+	err := s.InitParam(pserver.ParameterWithConfig{p, nil}, nil)
 	if err != nil {
 		t.FailNow()
 	}
 
-	err = s.FinishInitParams(0, &dummy)
+	err = s.FinishInitParams(0, nil)
 	if err != nil {
 		t.FailNow()
 	}