Merge pull request #2036 from xiang90/trtr

refactor rafthttp

rafthttp/http.go

@@ -159,14 +159,14 @@ func (h *streamHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	w.WriteHeader(http.StatusOK)
 	w.(http.Flusher).Flush()
 
-	stream := newStreamServer(w.(WriteFlusher), from, term)
-	err = p.attachStream(stream)
+	sw := newStreamWriter(w.(WriteFlusher), from, term)
+	err = p.attachStream(sw)
 	if err != nil {
 		log.Printf("rafthttp: %v", err)
 		http.Error(w, err.Error(), http.StatusBadRequest)
 		return
 	}
-	<-stream.stopNotify()
+	<-sw.stopNotify()
 }
 
 type writerToResponse interface {

rafthttp/peer.go

@@ -18,6 +18,7 @@ package rafthttp
 
 import (
 	"bytes"
+	"errors"
 	"fmt"
 	"log"
 	"net/http"
@@ -46,6 +47,8 @@ const (
 )
 
 type peer struct {
+	sync.Mutex
+
 	id  types.ID
 	cid types.ID
 
@@ -63,13 +66,14 @@ type peer struct {
 	// wait for the handling routines
 	wg sync.WaitGroup
 
-	mu sync.RWMutex
-	u  string // the url this sender post to
-	// if the last send was successful, thi sender is active.
+	// the url this sender post to
+	u string
+	// if the last send was successful, the sender is active.
 	// Or it is inactive
 	active  bool
 	errored error
 	paused  bool
+	stopped bool
 }
 
 func NewPeer(tr http.RoundTripper, u string, id types.ID, cid types.ID, r Raft, fs *stats.FollowerStats, errorc chan error) *peer {
@@ -95,8 +99,12 @@ func NewPeer(tr http.RoundTripper, u string, id types.ID, cid types.ID, r Raft,
 }
 
 func (p *peer) Update(u string) {
-	p.mu.Lock()
-	defer p.mu.Unlock()
+	p.Lock()
+	defer p.Unlock()
+	if p.stopped {
+		// TODO: not panic here?
+		panic("peer: update a stopped peer")
+	}
 	p.u = u
 }
 
@@ -104,19 +112,20 @@ func (p *peer) Update(u string) {
 // It may be fail to send data if it returns nil error.
 // TODO (xiangli): reasonable retry logic
 func (p *peer) Send(m raftpb.Message) error {
-	p.mu.RLock()
-	pause := p.paused
-	p.mu.RUnlock()
-	if pause {
+	p.Lock()
+	defer p.Unlock()
+	if p.stopped {
+		return errors.New("peer: stopped")
+	}
+	if p.paused {
 		return nil
 	}
 
 	// move all the stream related stuff into stream
 	p.stream.invalidate(m.Term)
 	if shouldInitStream(m) && !p.stream.isOpen() {
-		p.mu.Lock()
 		u := p.u
-		p.mu.Unlock()
+		// todo: steam open should not block.
 		p.stream.open(types.ID(m.From), p.id, p.cid, m.Term, p.tr, u, p.r)
 		p.batcher.Reset(time.Now())
 	}
@@ -168,7 +177,11 @@ func (p *peer) send(m raftpb.Message) error {
 func (p *peer) Stop() {
 	close(p.q)
 	p.wg.Wait()
+
+	p.Lock()
+	defer p.Unlock()
 	p.stream.stop()
+	p.stopped = true
 }
 
 func (p *peer) handle() {
@@ -178,7 +191,7 @@ func (p *peer) handle() {
 		err := p.post(pbutil.MustMarshal(m))
 		end := time.Now()
 
-		p.mu.Lock()
+		p.Lock()
 		if err != nil {
 			if p.errored == nil || p.errored.Error() != err.Error() {
 				log.Printf("sender: error posting to %s: %v", p.id, err)
@@ -201,16 +214,16 @@ func (p *peer) handle() {
 				p.fs.Succ(end.Sub(start))
 			}
 		}
-		p.mu.Unlock()
+		p.Unlock()
 	}
 }
 
 // post POSTs a data payload to a url. Returns nil if the POST succeeds,
 // error on any failure.
 func (p *peer) post(data []byte) error {
-	p.mu.RLock()
+	p.Lock()
 	req, err := http.NewRequest("POST", p.u, bytes.NewBuffer(data))
-	p.mu.RUnlock()
+	p.Unlock()
 	if err != nil {
 		return err
 	}
@@ -245,23 +258,29 @@ func (p *peer) post(data []byte) error {
 }
 
 // attachStream attaches a streamSever to the peer.
-func (p *peer) attachStream(server *streamServer) error {
-	server.fs = p.fs
-	return p.stream.attach(server)
+func (p *peer) attachStream(sw *streamWriter) error {
+	p.Lock()
+	defer p.Unlock()
+	if p.stopped {
+		return errors.New("peer: stopped")
+	}
+
+	sw.fs = p.fs
+	return p.stream.attach(sw)
 }
 
 // Pause pauses the peer. The peer will simply drops all incoming
 // messages without retruning an error.
 func (p *peer) Pause() {
-	p.mu.Lock()
-	defer p.mu.Unlock()
+	p.Lock()
+	defer p.Unlock()
 	p.paused = true
 }
 
 // Resume resumes a paused peer.
 func (p *peer) Resume() {
-	p.mu.Lock()
-	defer p.mu.Unlock()
+	p.Lock()
+	defer p.Unlock()
 	p.paused = false
 }
 

rafthttp/streamer.go

@@ -17,6 +17,7 @@
 package rafthttp
 
 import (
+	"errors"
 	"fmt"
 	"io"
 	"log"
@@ -41,60 +42,70 @@ const (
 
 // TODO: a stream might hava one stream server or one stream client, but not both.
 type stream struct {
-	// the server might be attached asynchronously with the owner of the stream
-	// use a mutex to protect it
 	sync.Mutex
-	server *streamServer
-
-	client *streamClient
+	w       *streamWriter
+	r       *streamReader
+	stopped bool
 }
 
 func (s *stream) open(from, to, cid types.ID, term uint64, tr http.RoundTripper, u string, r Raft) error {
-	if s.client != nil {
-		panic("open: stream is open")
-	}
-
-	c, err := newStreamClient(from, to, cid, term, tr, u, r)
+	rd, err := newStreamReader(from, to, cid, term, tr, u, r)
 	if err != nil {
 		log.Printf("stream: error opening stream: %v", err)
 		return err
 	}
-	s.client = c
+
+	s.Lock()
+	defer s.Unlock()
+	if s.stopped {
+		rd.stop()
+		return errors.New("stream: stopped")
+	}
+	if s.r != nil {
+		panic("open: stream is open")
+	}
+	s.r = rd
 	return nil
 }
 
-func (s *stream) attach(server *streamServer) error {
+func (s *stream) attach(sw *streamWriter) error {
 	s.Lock()
 	defer s.Unlock()
-	if s.server != nil {
+	if s.stopped {
+		return errors.New("stream: stopped")
+	}
+	if s.w != nil {
 		// ignore lower-term streaming request
-		if server.term < s.server.term {
-			return fmt.Errorf("cannot attach out of data stream server [%d / %d]", server.term, s.server.term)
+		if sw.term < s.w.term {
+			return fmt.Errorf("cannot attach out of data stream server [%d / %d]", sw.term, s.w.term)
 		}
-		s.server.stop()
+		s.w.stop()
 	}
-	s.server = server
+	s.w = sw
 	return nil
 }
 
 func (s *stream) write(m raftpb.Message) bool {
 	s.Lock()
 	defer s.Unlock()
-	if s.server == nil {
+	if s.stopped {
+		return false
+	}
+	if s.w == nil {
 		return false
 	}
-	if m.Term != s.server.term {
-		if m.Term > s.server.term {
+	if m.Term != s.w.term {
+		if m.Term > s.w.term {
 			panic("expected server to be invalidated when there is a higher term message")
 		}
 		return false
 	}
 	// todo: early unlock?
-	if err := s.server.send(m.Entries); err != nil {
+	if err := s.w.send(m.Entries); err != nil {
 		log.Printf("stream: error sending message: %v", err)
 		log.Printf("stream: stopping the stream server...")
-		s.server.stop()
-		s.server = nil
+		s.w.stop()
+		s.w = nil
 		return false
 	}
 	return true
@@ -105,19 +116,21 @@ func (s *stream) write(m raftpb.Message) bool {
 func (s *stream) invalidate(term uint64) {
 	s.Lock()
 	defer s.Unlock()
-
-	if s.server != nil {
-		if s.server.term < term {
-			s.server.stop()
-			s.server = nil
+	if s.w != nil {
+		if s.w.term < term {
+			s.w.stop()
+			s.w = nil
 		}
 	}
-	if s.client != nil {
-		if s.client.term < term {
-			s.client.stop()
-			s.client = nil
+	if s.r != nil {
+		if s.r.term < term {
+			s.r.stop()
+			s.r = nil
 		}
 	}
+	if term == math.MaxUint64 {
+		s.stopped = true
+	}
 }
 
 func (s *stream) stop() {
@@ -125,10 +138,12 @@ func (s *stream) stop() {
 }
 
 func (s *stream) isOpen() bool {
-	if s.client != nil && s.client.isStopped() {
-		s.client = nil
+	s.Lock()
+	defer s.Unlock()
+	if s.r != nil && s.r.isStopped() {
+		s.r = nil
 	}
-	return s.client != nil
+	return s.r != nil
 }
 
 type WriteFlusher interface {
@@ -136,9 +151,8 @@ type WriteFlusher interface {
 	http.Flusher
 }
 
-// TODO: rename it to streamWriter.
 // TODO: replace fs with stream stats
-type streamServer struct {
+type streamWriter struct {
 	to   types.ID
 	term uint64
 	fs   *stats.FollowerStats
@@ -148,8 +162,8 @@ type streamServer struct {
 
 // newStreamServer starts and returns a new started stream server.
 // The caller should call stop when finished, to shut it down.
-func newStreamServer(w WriteFlusher, to types.ID, term uint64) *streamServer {
-	s := &streamServer{
+func newStreamWriter(w WriteFlusher, to types.ID, term uint64) *streamWriter {
+	s := &streamWriter{
 		to:   to,
 		term: term,
 		q:    make(chan []raftpb.Entry, streamBufSize),
@@ -159,7 +173,7 @@ func newStreamServer(w WriteFlusher, to types.ID, term uint64) *streamServer {
 	return s
 }
 
-func (s *streamServer) send(ents []raftpb.Entry) error {
+func (s *streamWriter) send(ents []raftpb.Entry) error {
 	select {
 	case <-s.done:
 		return fmt.Errorf("stopped")
@@ -174,7 +188,7 @@ func (s *streamServer) send(ents []raftpb.Entry) error {
 	}
 }
 
-func (s *streamServer) handle(w WriteFlusher) {
+func (s *streamWriter) handle(w WriteFlusher) {
 	defer func() {
 		close(s.done)
 		log.Printf("rafthttp: server streaming to %s at term %d has been stopped", s.to, s.term)
@@ -192,16 +206,15 @@ func (s *streamServer) handle(w WriteFlusher) {
 	}
 }
 
-func (s *streamServer) stop() {
+func (s *streamWriter) stop() {
 	close(s.q)
 	<-s.done
 }
 
-func (s *streamServer) stopNotify() <-chan struct{} { return s.done }
+func (s *streamWriter) stopNotify() <-chan struct{} { return s.done }
 
-// TODO: rename it to streamReader.
 // TODO: move the raft interface out of the reader.
-type streamClient struct {
+type streamReader struct {
 	id   types.ID
 	to   types.ID
 	term uint64
@@ -213,8 +226,8 @@ type streamClient struct {
 
 // newStreamClient starts and returns a new started stream client.
 // The caller should call stop when finished, to shut it down.
-func newStreamClient(id, to, cid types.ID, term uint64, tr http.RoundTripper, u string, r Raft) (*streamClient, error) {
-	s := &streamClient{
+func newStreamReader(id, to, cid types.ID, term uint64, tr http.RoundTripper, u string, r Raft) (*streamReader, error) {
+	s := &streamReader{
 		id:   id,
 		to:   to,
 		term: term,
@@ -248,12 +261,12 @@ func newStreamClient(id, to, cid types.ID, term uint64, tr http.RoundTripper, u
 	return s, nil
 }
 
-func (s *streamClient) stop() {
+func (s *streamReader) stop() {
 	s.closer.Close()
 	<-s.done
 }
 
-func (s *streamClient) isStopped() bool {
+func (s *streamReader) isStopped() bool {
 	select {
 	case <-s.done:
 		return true
@@ -262,7 +275,7 @@ func (s *streamClient) isStopped() bool {
 	}
 }
 
-func (s *streamClient) handle(r io.Reader) {
+func (s *streamReader) handle(r io.Reader) {
 	defer func() {
 		close(s.done)
 		log.Printf("rafthttp: client streaming to %s at term %d has been stopped", s.to, s.term)