forked from etcd-io/etcd
/
snapshot_sender.go
161 lines (142 loc) · 4.54 KB
/
snapshot_sender.go
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// Copyright 2015 CoreOS, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package rafthttp
import (
"bytes"
"io"
"io/ioutil"
"net/http"
"time"
"github.com/coreos/etcd/pkg/httputil"
"github.com/coreos/etcd/pkg/types"
"github.com/coreos/etcd/raft"
"github.com/coreos/etcd/raft/raftpb"
)
type snapshotSender struct {
from, to types.ID
cid types.ID
tr http.RoundTripper
picker *urlPicker
status *peerStatus
snapst *snapshotStore
r Raft
errorc chan error
stopc chan struct{}
}
func newSnapshotSender(tr http.RoundTripper, picker *urlPicker, from, to, cid types.ID, status *peerStatus, snapst *snapshotStore, r Raft, errorc chan error) *snapshotSender {
return &snapshotSender{
from: from,
to: to,
cid: cid,
tr: tr,
picker: picker,
status: status,
snapst: snapst,
r: r,
errorc: errorc,
stopc: make(chan struct{}),
}
}
func (s *snapshotSender) stop() { close(s.stopc) }
func (s *snapshotSender) send(m raftpb.Message) {
start := time.Now()
body := createSnapBody(m, s.snapst)
defer body.Close()
u := s.picker.pick()
req := createPostRequest(u, RaftSnapshotPrefix, body, "application/octet-stream", s.from, s.cid)
err := s.post(req)
if err != nil {
// errMemberRemoved is a critical error since a removed member should
// always be stopped. So we use reportCriticalError to report it to errorc.
if err == errMemberRemoved {
reportCriticalError(err, s.errorc)
}
s.picker.unreachable(u)
reportSentFailure(sendSnap, m)
s.status.deactivate(failureType{source: sendSnap, action: "post"}, err.Error())
s.r.ReportUnreachable(m.To)
// report SnapshotFailure to raft state machine. After raft state
// machine knows about it, it would pause a while and retry sending
// new snapshot message.
s.r.ReportSnapshot(m.To, raft.SnapshotFailure)
if s.status.isActive() {
plog.Warningf("snapshot [index: %d, to: %s] failed to be sent out (%v)", m.Snapshot.Metadata.Index, types.ID(m.To), err)
} else {
plog.Debugf("snapshot [index: %d, to: %s] failed to be sent out (%v)", m.Snapshot.Metadata.Index, types.ID(m.To), err)
}
return
}
reportSentDuration(sendSnap, m, time.Since(start))
s.status.activate()
s.r.ReportSnapshot(m.To, raft.SnapshotFinish)
plog.Infof("snapshot [index: %d, to: %s] sent out successfully", m.Snapshot.Metadata.Index, types.ID(m.To))
}
// post posts the given request.
// It returns nil when request is sent out and processed successfully.
func (s *snapshotSender) post(req *http.Request) (err error) {
cancel := httputil.RequestCanceler(s.tr, req)
type responseAndError struct {
resp *http.Response
body []byte
err error
}
result := make(chan responseAndError, 1)
go func() {
// TODO: cancel the request if it has waited for a long time(~5s) after
// it has write out the full request body, which helps to avoid receiver
// dies when sender is waiting for response
// TODO: the snapshot could be large and eat up all resources when writing
// it out. Send it block by block and rest some time between to give the
// time for main loop to run.
resp, err := s.tr.RoundTrip(req)
if err != nil {
result <- responseAndError{resp, nil, err}
return
}
body, err := ioutil.ReadAll(resp.Body)
resp.Body.Close()
result <- responseAndError{resp, body, err}
}()
select {
case <-s.stopc:
cancel()
return errStopped
case r := <-result:
if r.err != nil {
return r.err
}
return checkPostResponse(r.resp, r.body, req, s.to)
}
}
// readCloser implements io.ReadCloser interface.
type readCloser struct {
io.Reader
io.Closer
}
// createSnapBody creates the request body for the given raft snapshot message.
// Callers should close body when done reading from it.
func createSnapBody(m raftpb.Message, snapst *snapshotStore) io.ReadCloser {
buf := new(bytes.Buffer)
enc := &messageEncoder{w: buf}
// encode raft message
if err := enc.encode(m); err != nil {
plog.Panicf("encode message error (%v)", err)
}
// get snapshot
rc := snapst.get(m.Snapshot.Metadata.Index)
return &readCloser{
Reader: io.MultiReader(buf, rc),
Closer: rc,
}
}