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rafthttp: add stream

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This commit is contained in:
Xiang Li 2014-12-30 13:45:11 -08:00
parent f79b9042ab
commit 2193b70fb3
3 changed files with 173 additions and 139 deletions
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10
rafthttp/http.go
View File

@ -159,14 +159,14 @@ func (h *streamHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
w.WriteHeader(http.StatusOK)
w.(http.Flusher).Flush()
done, err := p.StartStreaming(w.(WriteFlusher), from, term)
stream := newStreamServer(w.(WriteFlusher), from, term)
err = p.attachStream(stream)
if err != nil {
log.Printf("rafthttp: streaming request ignored due to start streaming error: %v", err)
// TODO: consider http status and info here
http.Error(w, "error enable streaming", http.StatusInternalServerError)
log.Printf("rafthttp: %v", err)
http.Error(w, err.Error(), http.StatusBadRequest)
return
}
<-done
<-stream.stopNotify()
}
type writerToResponse interface {

163
rafthttp/peer.go
View File

@ -45,27 +45,6 @@ const (
ConnWriteTimeout = 5 * time.Second
)
func NewPeer(tr http.RoundTripper, u string, id types.ID, cid types.ID, r Raft, fs *stats.FollowerStats, shouldstop chan struct{}) *peer {
p := &peer{
id: id,
active: true,
tr: tr,
u: u,
cid: cid,
r: r,
fs: fs,
shouldstop: shouldstop,
batcher: NewBatcher(100, appRespBatchMs*time.Millisecond),
propBatcher: NewProposalBatcher(100, propBatchMs*time.Millisecond),
q: make(chan *raftpb.Message, senderBufSize),
}
p.wg.Add(connPerSender)
for i := 0; i < connPerSender; i++ {
go p.handle()
}
return p
}
type peer struct {
id types.ID
cid types.ID
@ -75,13 +54,11 @@ type peer struct {
fs *stats.FollowerStats
shouldstop chan struct{}
strmCln *streamClient
batcher *Batcher
propBatcher *ProposalBatcher
q chan *raftpb.Message
strmSrvMu sync.Mutex
strmSrv *streamServer
stream *stream
// wait for the handling routines
wg sync.WaitGroup
@ -95,22 +72,26 @@ type peer struct {
paused bool
}
// StartStreaming enables streaming in the peer using the given writer,
// which provides a fast and efficient way to send appendEntry messages.
func (p *peer) StartStreaming(w WriteFlusher, to types.ID, term uint64) (<-chan struct{}, error) {
p.strmSrvMu.Lock()
defer p.strmSrvMu.Unlock()
if p.strmSrv != nil {
// ignore lower-term streaming request
if term < p.strmSrv.term {
return nil, fmt.Errorf("out of data streaming request: term %d, request term %d", term, p.strmSrv.term)
}
// stop the existing one
p.strmSrv.stop()
p.strmSrv = nil
func NewPeer(tr http.RoundTripper, u string, id types.ID, cid types.ID, r Raft, fs *stats.FollowerStats, shouldstop chan struct{}) *peer {
p := &peer{
id: id,
active: true,
tr: tr,
u: u,
cid: cid,
r: r,
fs: fs,
stream: &stream{},
shouldstop: shouldstop,
batcher: NewBatcher(100, appRespBatchMs*time.Millisecond),
propBatcher: NewProposalBatcher(100, propBatchMs*time.Millisecond),
q: make(chan *raftpb.Message, senderBufSize),
}
p.strmSrv = startStreamServer(w, to, term, p.fs)
return p.strmSrv.stopNotify(), nil
p.wg.Add(connPerSender)
for i := 0; i < connPerSender; i++ {
go p.handle()
}
return p
}
func (p *peer) Update(u string) {
@ -130,9 +111,13 @@ func (p *peer) Send(m raftpb.Message) error {
return nil
}
p.maybeStopStream(m.Term)
if shouldInitStream(m) && !p.hasStreamClient() {
p.initStream(types.ID(m.From), types.ID(m.To), m.Term)
// 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()
p.stream.open(p.id, types.ID(m.To), p.cid, m.Term, p.tr, u, p.r)
p.batcher.Reset(time.Now())
}
@ -140,12 +125,12 @@ func (p *peer) Send(m raftpb.Message) error {
switch {
case isProposal(m):
p.propBatcher.Batch(m)
case canBatch(m) && p.hasStreamClient():
case canBatch(m) && p.stream.isOpen():
if !p.batcher.ShouldBatch(time.Now()) {
err = p.send(m)
}
case canUseStream(m):
if ok := p.tryStream(m); !ok {
if ok := p.stream.write(m); !ok {
err = p.send(m)
}
default:
@ -183,74 +168,7 @@ func (p *peer) send(m raftpb.Message) error {
func (p *peer) Stop() {
close(p.q)
p.wg.Wait()
p.strmSrvMu.Lock()
if p.strmSrv != nil {
p.strmSrv.stop()
p.strmSrv = nil
}
p.strmSrvMu.Unlock()
if p.strmCln != nil {
p.strmCln.stop()
}
}
// 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.paused = true
}
// Resume resumes a paused peer.
func (p *peer) Resume() {
p.mu.Lock()
defer p.mu.Unlock()
p.paused = false
}
func (p *peer) maybeStopStream(term uint64) {
if p.strmCln != nil && term > p.strmCln.term {
p.strmCln.stop()
p.strmCln = nil
}
p.strmSrvMu.Lock()
defer p.strmSrvMu.Unlock()
if p.strmSrv != nil && term > p.strmSrv.term {
p.strmSrv.stop()
p.strmSrv = nil
}
}
func (p *peer) hasStreamClient() bool {
return p.strmCln != nil && !p.strmCln.isStopped()
}
func (p *peer) initStream(from, to types.ID, term uint64) {
strmCln := newStreamClient(from, to, term, p.r)
p.mu.Lock()
u := p.u
p.mu.Unlock()
if err := strmCln.start(p.tr, u, p.cid); err != nil {
log.Printf("rafthttp: start stream client error: %v", err)
return
}
p.strmCln = strmCln
}
func (p *peer) tryStream(m raftpb.Message) bool {
p.strmSrvMu.Lock()
defer p.strmSrvMu.Unlock()
if p.strmSrv == nil || m.Term != p.strmSrv.term {
return false
}
if err := p.strmSrv.send(m.Entries); err != nil {
log.Printf("rafthttp: send stream message error: %v", err)
p.strmSrv.stop()
p.strmSrv = nil
return false
}
return true
p.stream.stop()
}
func (p *peer) handle() {
@ -327,4 +245,25 @@ 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)
}
// 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.paused = true
}
// Resume resumes a paused peer.
func (p *peer) Resume() {
p.mu.Lock()
defer p.mu.Unlock()
p.paused = false
}
func isProposal(m raftpb.Message) bool { return m.Type == raftpb.MsgProp }

139
rafthttp/streamer.go
View File

@ -20,10 +20,12 @@ import (
"fmt"
"io"
"log"
"math"
"net/http"
"net/url"
"path"
"strconv"
"sync"
"time"
"github.com/coreos/etcd/etcdserver/stats"
@ -37,11 +39,105 @@ const (
streamBufSize = 4096
)
// 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
}
func (s *stream) open(id, 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(id, to, cid, term, tr, u, r)
if err != nil {
log.Printf("stream: error opening stream: %v", err)
return err
}
s.client = c
return nil
}
func (s *stream) attach(server *streamServer) error {
s.Lock()
defer s.Unlock()
if s.server != 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)
}
s.server.stop()
}
s.server = server
return nil
}
func (s *stream) write(m raftpb.Message) bool {
s.Lock()
defer s.Unlock()
if s.server == nil {
return false
}
if m.Term != s.server.term {
if m.Term > s.server.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 {
log.Printf("stream: error sending message: %v", err)
log.Printf("stream: stopping the stream server...")
s.server.stop()
s.server = nil
return false
}
return true
}
// invalidate stops the sever/client that is running at
// a term lower than the given term.
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.client != nil {
if s.client.term < term {
s.client.stop()
s.client = nil
}
}
}
func (s *stream) stop() {
s.invalidate(math.MaxUint64)
}
func (s *stream) isOpen() bool {
if s.client != nil && s.client.isStopped() {
s.client = nil
}
return s.client != nil
}
type WriteFlusher interface {
io.Writer
http.Flusher
}
// TODO: rename it to streamWriter.
// TODO: replace fs with stream stats
type streamServer struct {
to types.ID
term uint64
@ -50,16 +146,16 @@ type streamServer struct {
done chan struct{}
}
func startStreamServer(w WriteFlusher, to types.ID, term uint64, fs *stats.FollowerStats) *streamServer {
// 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{
to: to,
term: term,
fs: fs,
q: make(chan []raftpb.Entry, streamBufSize),
done: make(chan struct{}),
}
go s.handle(w)
log.Printf("rafthttp: starting server stream to %s at term %d", to, term)
return s
}
@ -78,13 +174,6 @@ func (s *streamServer) send(ents []raftpb.Entry) error {
}
}
func (s *streamServer) stop() {
close(s.q)
<-s.done
}
func (s *streamServer) stopNotify() <-chan struct{} { return s.done }
func (s *streamServer) handle(w WriteFlusher) {
defer func() {
close(s.done)
@ -103,6 +192,15 @@ func (s *streamServer) handle(w WriteFlusher) {
}
}
func (s *streamServer) stop() {
close(s.q)
<-s.done
}
func (s *streamServer) stopNotify() <-chan struct{} { return s.done }
// TODO: rename it to streamReader.
// TODO: move the raft interface out of the reader.
type streamClient struct {
id types.ID
to types.ID
@ -113,44 +211,41 @@ type streamClient struct {
done chan struct{}
}
func newStreamClient(id, to types.ID, term uint64, r Raft) *streamClient {
return &streamClient{
// 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{
id: id,
to: to,
term: term,
r: r,
done: make(chan struct{}),
}
}
// Dial dials to the remote url, and sends streaming request. If it succeeds,
// it returns nil error, and the caller should call Handle function to keep
// receiving appendEntry messages.
func (s *streamClient) start(tr http.RoundTripper, u string, cid types.ID) error {
uu, err := url.Parse(u)
if err != nil {
return fmt.Errorf("parse url %s error: %v", u, err)
return nil, fmt.Errorf("parse url %s error: %v", u, err)
}
uu.Path = path.Join(RaftStreamPrefix, s.id.String())
req, err := http.NewRequest("GET", uu.String(), nil)
if err != nil {
return fmt.Errorf("new request to %s error: %v", u, err)
return nil, fmt.Errorf("new request to %s error: %v", u, err)
}
req.Header.Set("X-Etcd-Cluster-ID", cid.String())
req.Header.Set("X-Raft-To", s.to.String())
req.Header.Set("X-Raft-Term", strconv.FormatUint(s.term, 10))
resp, err := tr.RoundTrip(req)
if err != nil {
return fmt.Errorf("error posting to %q: %v", u, err)
return nil, fmt.Errorf("error posting to %q: %v", u, err)
}
if resp.StatusCode != http.StatusOK {
resp.Body.Close()
return fmt.Errorf("unhandled http status %d", resp.StatusCode)
return nil, fmt.Errorf("unhandled http status %d", resp.StatusCode)
}
s.closer = resp.Body
go s.handle(resp.Body)
log.Printf("rafthttp: starting client stream to %s at term %d", s.to, s.term)
return nil
return s, nil
}
func (s *streamClient) stop() {