func (enc *messageEncoder) encode(m raftpb.Message) error {
if err := binary.Write(enc.w, binary.BigEndian, uint64(m.Size())); err != nil {
return err
}
_, err := enc.w.Write(pbutil.MustMarshal(&m))
return err
}
// send persists state to stable storage and then sends to its mailbox.
func (r *raft) send(m pb.Message) {
m.From = r.id
// do not attach term to MsgProp
// proposals are a way to forward to the leader and
// should be treated as local message.
if m.Type != pb.MsgProp {
m.Term = r.Term
}
r.msgs = append(r.msgs, m)
}
func (dec *messageDecoder) decode() (raftpb.Message, error) {
var m raftpb.Message
var l uint64
if err := binary.Read(dec.r, binary.BigEndian, &l); err != nil {
return m, err
}
buf := make([]byte, int(l))
if _, err := io.ReadFull(dec.r, buf); err != nil {
return m, err
}
return m, m.Unmarshal(buf)
}
func stepFollower(r *raft, m pb.Message) {
switch m.Type {
case pb.MsgProp:
if r.lead == None {
r.logger.Infof("%x no leader at term %d; dropping proposal", r.id, r.Term)
return
}
m.To = r.lead
r.send(m)
case pb.MsgApp:
r.elapsed = 0
r.lead = m.From
r.handleAppendEntries(m)
case pb.MsgHeartbeat:
r.elapsed = 0
r.lead = m.From
r.handleHeartbeat(m)
case pb.MsgSnap:
r.elapsed = 0
r.handleSnapshot(m)
case pb.MsgVote:
if (r.Vote == None || r.Vote == m.From) && r.raftLog.isUpToDate(m.Index, m.LogTerm) {
r.elapsed = 0
r.logger.Infof("%x [logterm: %d, index: %d, vote: %x] voted for %x [logterm: %d, index: %d] at term %d",
r.id, r.raftLog.lastTerm(), r.raftLog.lastIndex(), r.Vote, m.From, m.LogTerm, m.Index, r.Term)
r.Vote = m.From
r.send(pb.Message{To: m.From, Type: pb.MsgVoteResp})
} else {
r.logger.Infof("%x [logterm: %d, index: %d, vote: %x] rejected vote from %x [logterm: %d, index: %d] at term %d",
r.id, r.raftLog.lastTerm(), r.raftLog.lastIndex(), r.Vote, m.From, m.LogTerm, m.Index, r.Term)
r.send(pb.Message{To: m.From, Type: pb.MsgVoteResp, Reject: true})
}
}
}
// sendAppend sends RRPC, with entries to the given peer.
func (r *raft) sendAppend(to uint64) {
pr := r.prs[to]
if pr.isPaused() {
return
}
m := pb.Message{}
m.To = to
term, errt := r.raftLog.term(pr.Next - 1)
ents, erre := r.raftLog.entries(pr.Next, r.maxMsgSize)
if errt != nil || erre != nil { // send snapshot if we failed to get term or entries
m.Type = pb.MsgSnap
snapshot, err := r.raftLog.snapshot()
if err != nil {
if err == ErrSnapshotTemporarilyUnavailable {
r.logger.Debugf("%x failed to send snapshot to %x because snapshot is temporarily unavailable", r.id, to)
return
}
panic(err) // TODO(bdarnell)
}
if IsEmptySnap(snapshot) {
panic("need non-empty snapshot")
}
m.Snapshot = snapshot
sindex, sterm := snapshot.Metadata.Index, snapshot.Metadata.Term
r.logger.Debugf("%x [firstindex: %d, commit: %d] sent snapshot[index: %d, term: %d] to %x [%s]",
r.id, r.raftLog.firstIndex(), r.Commit, sindex, sterm, to, pr)
pr.becomeSnapshot(sindex)
r.logger.Debugf("%x paused sending replication messages to %x [%s]", r.id, to, pr)
} else {
m.Type = pb.MsgApp
m.Index = pr.Next - 1
m.LogTerm = term
m.Entries = ents
m.Commit = r.raftLog.committed
if n := len(m.Entries); n != 0 {
switch pr.State {
// optimistically increase the next when in ProgressStateReplicate
case ProgressStateReplicate:
last := m.Entries[n-1].Index
pr.optimisticUpdate(last)
pr.ins.add(last)
case ProgressStateProbe:
pr.pause()
default:
r.logger.Panicf("%x is sending append in unhandled state %s", r.id, pr.State)
}
}
}
r.send(m)
}
func (h *handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
if r.Method != "POST" {
w.Header().Set("Allow", "POST")
http.Error(w, "Method Not Allowed", http.StatusMethodNotAllowed)
return
}
w.Header().Set("X-Etcd-Cluster-ID", h.cid.String())
if err := checkClusterCompatibilityFromHeader(r.Header, h.cid); err != nil {
http.Error(w, err.Error(), http.StatusPreconditionFailed)
return
}
// Limit the data size that could be read from the request body, which ensures that read from
// connection will not time out accidentally due to possible block in underlying implementation.
limitedr := pioutil.NewLimitedBufferReader(r.Body, ConnReadLimitByte)
b, err := ioutil.ReadAll(limitedr)
if err != nil {
plog.Errorf("failed to read raft message (%v)", err)
http.Error(w, "error reading raft message", http.StatusBadRequest)
return
}
var m raftpb.Message
if err := m.Unmarshal(b); err != nil {
plog.Errorf("failed to unmarshal raft message (%v)", err)
http.Error(w, "error unmarshaling raft message", http.StatusBadRequest)
return
}
if err := h.r.Process(context.TODO(), m); err != nil {
switch v := err.(type) {
case writerToResponse:
v.WriteTo(w)
default:
plog.Warningf("failed to process raft message (%v)", err)
http.Error(w, "error processing raft message", http.StatusInternalServerError)
}
return
}
// Write StatusNoContet header after the message has been processed by
// raft, which facilitates the client to report MsgSnap status.
w.WriteHeader(http.StatusNoContent)
}
func (enc *msgAppV2Encoder) encode(m raftpb.Message) error {
start := time.Now()
switch {
case isLinkHeartbeatMessage(m):
enc.uint8buf[0] = byte(msgTypeLinkHeartbeat)
if _, err := enc.w.Write(enc.uint8buf); err != nil {
return err
}
case enc.index == m.Index && enc.term == m.LogTerm && m.LogTerm == m.Term:
enc.uint8buf[0] = byte(msgTypeAppEntries)
if _, err := enc.w.Write(enc.uint8buf); err != nil {
return err
}
// write length of entries
binary.BigEndian.PutUint64(enc.uint64buf, uint64(len(m.Entries)))
if _, err := enc.w.Write(enc.uint64buf); err != nil {
return err
}
for i := 0; i < len(m.Entries); i++ {
// write length of entry
binary.BigEndian.PutUint64(enc.uint64buf, uint64(m.Entries[i].Size()))
if _, err := enc.w.Write(enc.uint64buf); err != nil {
return err
}
if n := m.Entries[i].Size(); n < msgAppV2BufSize {
if _, err := m.Entries[i].MarshalTo(enc.buf); err != nil {
return err
}
if _, err := enc.w.Write(enc.buf[:n]); err != nil {
return err
}
} else {
if _, err := enc.w.Write(pbutil.MustMarshal(&m.Entries[i])); err != nil {
return err
}
}
enc.index++
}
// write commit index
binary.BigEndian.PutUint64(enc.uint64buf, m.Commit)
if _, err := enc.w.Write(enc.uint64buf); err != nil {
return err
}
enc.fs.Succ(time.Since(start))
default:
if err := binary.Write(enc.w, binary.BigEndian, msgTypeApp); err != nil {
return err
}
// write size of message
if err := binary.Write(enc.w, binary.BigEndian, uint64(m.Size())); err != nil {
return err
}
// write message
if _, err := enc.w.Write(pbutil.MustMarshal(&m)); err != nil {
return err
}
enc.term = m.Term
enc.index = m.Index
if l := len(m.Entries); l > 0 {
enc.index = m.Entries[l-1].Index
}
enc.fs.Succ(time.Since(start))
}
return nil
}
func (dec *msgAppV2Decoder) decode() (raftpb.Message, error) {
var (
m raftpb.Message
typ uint8
)
if _, err := io.ReadFull(dec.r, dec.uint8buf); err != nil {
return m, err
}
typ = uint8(dec.uint8buf[0])
switch typ {
case msgTypeLinkHeartbeat:
return linkHeartbeatMessage, nil
case msgTypeAppEntries:
m = raftpb.Message{
Type: raftpb.MsgApp,
From: uint64(dec.remote),
To: uint64(dec.local),
Term: dec.term,
LogTerm: dec.term,
Index: dec.index,
}
// decode entries
if _, err := io.ReadFull(dec.r, dec.uint64buf); err != nil {
return m, err
}
l := binary.BigEndian.Uint64(dec.uint64buf)
m.Entries = make([]raftpb.Entry, int(l))
for i := 0; i < int(l); i++ {
if _, err := io.ReadFull(dec.r, dec.uint64buf); err != nil {
return m, err
}
size := binary.BigEndian.Uint64(dec.uint64buf)
var buf []byte
if size < msgAppV2BufSize {
buf = dec.buf[:size]
if _, err := io.ReadFull(dec.r, buf); err != nil {
return m, err
}
} else {
buf = make([]byte, int(size))
if _, err := io.ReadFull(dec.r, buf); err != nil {
return m, err
}
}
dec.index++
// 1 alloc
pbutil.MustUnmarshal(&m.Entries[i], buf)
}
// decode commit index
if _, err := io.ReadFull(dec.r, dec.uint64buf); err != nil {
return m, err
}
m.Commit = binary.BigEndian.Uint64(dec.uint64buf)
case msgTypeApp:
var size uint64
if err := binary.Read(dec.r, binary.BigEndian, &size); err != nil {
return m, err
}
buf := make([]byte, int(size))
if _, err := io.ReadFull(dec.r, buf); err != nil {
return m, err
}
pbutil.MustUnmarshal(&m, buf)
dec.term = m.Term
dec.index = m.Index
if l := len(m.Entries); l > 0 {
dec.index = m.Entries[l-1].Index
}
default:
return m, fmt.Errorf("failed to parse type %d in msgappv2 stream", typ)
}
return m, nil
}