https://github.com/etcd-io/etcd
Tip revision: 2d861f39e9ec31dd9129a8070e8ff6492f859c07 authored by Sam Batschelet on 03 November 2019, 12:33:22 UTC
version: 3.2.28
version: 3.2.28
Tip revision: 2d861f3
snapshot_sender.go
// Copyright 2015 The etcd Authors
//
// 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"
"context"
"io"
"io/ioutil"
"net/http"
"time"
"github.com/coreos/etcd/pkg/httputil"
pioutil "github.com/coreos/etcd/pkg/ioutil"
"github.com/coreos/etcd/pkg/types"
"github.com/coreos/etcd/raft"
"github.com/coreos/etcd/snap"
)
var (
// timeout for reading snapshot response body
snapResponseReadTimeout = 5 * time.Second
)
type snapshotSender struct {
from, to types.ID
cid types.ID
tr *Transport
picker *urlPicker
status *peerStatus
r Raft
errorc chan error
stopc chan struct{}
}
func newSnapshotSender(tr *Transport, picker *urlPicker, to types.ID, status *peerStatus) *snapshotSender {
return &snapshotSender{
from: tr.ID,
to: to,
cid: tr.ClusterID,
tr: tr,
picker: picker,
status: status,
r: tr.Raft,
errorc: tr.ErrorC,
stopc: make(chan struct{}),
}
}
func (s *snapshotSender) stop() { close(s.stopc) }
func (s *snapshotSender) send(merged snap.Message) {
start := time.Now()
m := merged.Message
to := types.ID(m.To).String()
body := createSnapBody(merged)
defer body.Close()
u := s.picker.pick()
req := createPostRequest(u, RaftSnapshotPrefix, body, "application/octet-stream", s.tr.URLs, s.from, s.cid)
plog.Infof("start to send database snapshot [index: %d, to %s]...", m.Snapshot.Metadata.Index, types.ID(m.To))
err := s.post(req)
defer merged.CloseWithError(err)
if err != nil {
plog.Warningf("database snapshot [index: %d, to: %s] failed to be sent out (%v)", m.Snapshot.Metadata.Index, types.ID(m.To), err)
// 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)
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)
sentFailures.WithLabelValues(to).Inc()
snapshotSendFailures.WithLabelValues(to).Inc()
return
}
s.status.activate()
s.r.ReportSnapshot(m.To, raft.SnapshotFinish)
plog.Infof("database snapshot [index: %d, to: %s] sent out successfully", m.Snapshot.Metadata.Index, types.ID(m.To))
sentBytes.WithLabelValues(to).Add(float64(merged.TotalSize))
snapshotSend.WithLabelValues(to).Inc()
snapshotSendSeconds.WithLabelValues(to).Observe(time.Since(start).Seconds())
}
// 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) {
ctx, cancel := context.WithCancel(context.Background())
req = req.WithContext(ctx)
defer cancel()
type responseAndError struct {
resp *http.Response
body []byte
err error
}
result := make(chan responseAndError, 1)
go func() {
resp, err := s.tr.pipelineRt.RoundTrip(req)
if err != nil {
result <- responseAndError{resp, nil, err}
return
}
// close the response body when timeouts.
// prevents from reading the body forever when the other side dies right after
// successfully receives the request body.
time.AfterFunc(snapResponseReadTimeout, func() { httputil.GracefulClose(resp) })
body, err := ioutil.ReadAll(resp.Body)
result <- responseAndError{resp, body, err}
}()
select {
case <-s.stopc:
return errStopped
case r := <-result:
if r.err != nil {
return r.err
}
return checkPostResponse(r.resp, r.body, req, s.to)
}
}
func createSnapBody(merged snap.Message) io.ReadCloser {
buf := new(bytes.Buffer)
enc := &messageEncoder{w: buf}
// encode raft message
if err := enc.encode(&merged.Message); err != nil {
plog.Panicf("encode message error (%v)", err)
}
return &pioutil.ReaderAndCloser{
Reader: io.MultiReader(buf, merged.ReadCloser),
Closer: merged.ReadCloser,
}
}