go.etcd.io/etcd@v3.3.27+incompatible/rafthttp/pipeline.go (about)

     1  // Copyright 2015 The etcd Authors
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package rafthttp
    16  
    17  import (
    18  	"bytes"
    19  	"context"
    20  	"errors"
    21  	"io/ioutil"
    22  	"sync"
    23  	"time"
    24  
    25  	"github.com/coreos/etcd/etcdserver/stats"
    26  	"github.com/coreos/etcd/pkg/pbutil"
    27  	"github.com/coreos/etcd/pkg/types"
    28  	"github.com/coreos/etcd/raft"
    29  	"github.com/coreos/etcd/raft/raftpb"
    30  )
    31  
    32  const (
    33  	connPerPipeline = 4
    34  	// pipelineBufSize is the size of pipeline buffer, which helps hold the
    35  	// temporary network latency.
    36  	// The size ensures that pipeline does not drop messages when the network
    37  	// is out of work for less than 1 second in good path.
    38  	pipelineBufSize = 64
    39  )
    40  
    41  var errStopped = errors.New("stopped")
    42  
    43  type pipeline struct {
    44  	peerID types.ID
    45  
    46  	tr     *Transport
    47  	picker *urlPicker
    48  	status *peerStatus
    49  	raft   Raft
    50  	errorc chan error
    51  	// deprecate when we depercate v2 API
    52  	followerStats *stats.FollowerStats
    53  
    54  	msgc chan raftpb.Message
    55  	// wait for the handling routines
    56  	wg    sync.WaitGroup
    57  	stopc chan struct{}
    58  }
    59  
    60  func (p *pipeline) start() {
    61  	p.stopc = make(chan struct{})
    62  	p.msgc = make(chan raftpb.Message, pipelineBufSize)
    63  	p.wg.Add(connPerPipeline)
    64  	for i := 0; i < connPerPipeline; i++ {
    65  		go p.handle()
    66  	}
    67  	plog.Infof("started HTTP pipelining with peer %s", p.peerID)
    68  }
    69  
    70  func (p *pipeline) stop() {
    71  	close(p.stopc)
    72  	p.wg.Wait()
    73  	plog.Infof("stopped HTTP pipelining with peer %s", p.peerID)
    74  }
    75  
    76  func (p *pipeline) handle() {
    77  	defer p.wg.Done()
    78  
    79  	for {
    80  		select {
    81  		case m := <-p.msgc:
    82  			start := time.Now()
    83  			err := p.post(pbutil.MustMarshal(&m))
    84  			end := time.Now()
    85  
    86  			if err != nil {
    87  				p.status.deactivate(failureType{source: pipelineMsg, action: "write"}, err.Error())
    88  
    89  				if m.Type == raftpb.MsgApp && p.followerStats != nil {
    90  					p.followerStats.Fail()
    91  				}
    92  				p.raft.ReportUnreachable(m.To)
    93  				if isMsgSnap(m) {
    94  					p.raft.ReportSnapshot(m.To, raft.SnapshotFailure)
    95  				}
    96  				sentFailures.WithLabelValues(types.ID(m.To).String()).Inc()
    97  				continue
    98  			}
    99  
   100  			p.status.activate()
   101  			if m.Type == raftpb.MsgApp && p.followerStats != nil {
   102  				p.followerStats.Succ(end.Sub(start))
   103  			}
   104  			if isMsgSnap(m) {
   105  				p.raft.ReportSnapshot(m.To, raft.SnapshotFinish)
   106  			}
   107  			sentBytes.WithLabelValues(types.ID(m.To).String()).Add(float64(m.Size()))
   108  		case <-p.stopc:
   109  			return
   110  		}
   111  	}
   112  }
   113  
   114  // post POSTs a data payload to a url. Returns nil if the POST succeeds,
   115  // error on any failure.
   116  func (p *pipeline) post(data []byte) (err error) {
   117  	u := p.picker.pick()
   118  	req := createPostRequest(u, RaftPrefix, bytes.NewBuffer(data), "application/protobuf", p.tr.URLs, p.tr.ID, p.tr.ClusterID)
   119  
   120  	done := make(chan struct{}, 1)
   121  	ctx, cancel := context.WithCancel(context.Background())
   122  	req = req.WithContext(ctx)
   123  	go func() {
   124  		select {
   125  		case <-done:
   126  		case <-p.stopc:
   127  			waitSchedule()
   128  			cancel()
   129  		}
   130  	}()
   131  
   132  	resp, err := p.tr.pipelineRt.RoundTrip(req)
   133  	done <- struct{}{}
   134  	if err != nil {
   135  		p.picker.unreachable(u)
   136  		return err
   137  	}
   138  	b, err := ioutil.ReadAll(resp.Body)
   139  	if err != nil {
   140  		p.picker.unreachable(u)
   141  		return err
   142  	}
   143  	resp.Body.Close()
   144  
   145  	err = checkPostResponse(resp, b, req, p.peerID)
   146  	if err != nil {
   147  		p.picker.unreachable(u)
   148  		// errMemberRemoved is a critical error since a removed member should
   149  		// always be stopped. So we use reportCriticalError to report it to errorc.
   150  		if err == errMemberRemoved {
   151  			reportCriticalError(err, p.errorc)
   152  		}
   153  		return err
   154  	}
   155  
   156  	return nil
   157  }
   158  
   159  // waitSchedule waits other goroutines to be scheduled for a while
   160  func waitSchedule() { time.Sleep(time.Millisecond) }