// NewListener creates a net.Listener
// If the given scheme is "https", it will use TLS config to set listener.
// If any error happens, this function will call log.Fatal
func NewListener(scheme, addr string, cfg *tls.Config) net.Listener {
	if scheme == "https" {
		l, err := newTLSListener(addr, cfg)
		if err != nil {
			log.Fatal("Failed to create TLS listener: ", err)
		}
		return l
	}

	l, err := newListener(addr)
	if err != nil {
		log.Fatal("Failed to create listener: ", err)
	}
	return l
}

func (e *Etcd) runServer() {
	var removeNotify <-chan bool
	for {
		if e.mode == PeerMode {
			log.Infof("%v starting in peer mode", e.Config.Name)
			// Starting peer server should be followed close by listening on its port
			// If not, it may leave many requests unaccepted, or cannot receive heartbeat from the cluster.
			// One severe problem caused if failing receiving heartbeats is when the second node joins one-node cluster,
			// the cluster could be out of work as long as the two nodes cannot transfer messages.
			e.PeerServer.Start(e.Config.Snapshot, e.Config.ClusterConfig())
			removeNotify = e.PeerServer.RemoveNotify()
		} else {
			log.Infof("%v starting in standby mode", e.Config.Name)
			e.StandbyServer.Start()
			removeNotify = e.StandbyServer.RemoveNotify()
		}

		// etcd server is ready to accept connections, notify waiters.
		e.onceReady.Do(func() { close(e.readyNotify) })

		select {
		case <-e.closeChan:
			e.PeerServer.Stop()
			e.StandbyServer.Stop()
			return
		case <-removeNotify:
		}

		if e.mode == PeerMode {
			peerURLs := e.Registry.PeerURLs(e.PeerServer.RaftServer().Leader(), e.Config.Name)
			e.StandbyServer.SyncCluster(peerURLs)
			e.setMode(StandbyMode)
		} else {
			// Create etcd key-value store and registry.
			e.Store = store.New()
			e.Registry = server.NewRegistry(e.Store)
			e.PeerServer.SetStore(e.Store)
			e.PeerServer.SetRegistry(e.Registry)
			e.Server.SetStore(e.Store)
			e.Server.SetRegistry(e.Registry)

			// Generate new peer server here.
			// TODO(yichengq): raft server cannot be started after stopped.
			// It should be removed when raft restart is implemented.
			heartbeatInterval := time.Duration(e.Config.Peer.HeartbeatInterval) * time.Millisecond
			electionTimeout := time.Duration(e.Config.Peer.ElectionTimeout) * time.Millisecond
			raftServer, err := raft.NewServer(e.Config.Name, e.Config.DataDir, e.PeerServer.RaftServer().Transporter(), e.Store, e.PeerServer, "")
			if err != nil {
				log.Fatal(err)
			}
			raftServer.SetElectionTimeout(electionTimeout)
			raftServer.SetHeartbeatInterval(heartbeatInterval)
			e.PeerServer.SetRaftServer(raftServer, e.Config.Snapshot)
			e.StandbyServer.SetRaftServer(raftServer)

			e.PeerServer.SetJoinIndex(e.StandbyServer.JoinIndex())
			e.setMode(PeerMode)
		}
	}
}

// Parses non-configuration flags.
func parseFlags() {
	var versionFlag bool
	var cpuprofile string

	f := flag.NewFlagSet(os.Args[0], -1)
	f.SetOutput(ioutil.Discard)
	f.BoolVar(&versionFlag, "version", false, "print the version and exit")
	f.StringVar(&cpuprofile, "cpuprofile", "", "write cpu profile to file")
	f.Parse(os.Args[1:])

	// Print version if necessary.
	if versionFlag {
		fmt.Println(server.ReleaseVersion)
		os.Exit(0)
	}

	// Begin CPU profiling if specified.
	if cpuprofile != "" {
		f, err := os.Create(cpuprofile)
		if err != nil {
			log.Fatal(err)
		}
		pprof.StartCPUProfile(f)

		c := make(chan os.Signal, 1)
		signal.Notify(c, os.Interrupt)
		go func() {
			sig := <-c
			log.Infof("captured %v, stopping profiler and exiting..", sig)
			pprof.StopCPUProfile()
			os.Exit(1)
		}()
	}
}

// NameFromHostname sets the machine name from the hostname. This is to help
// people get started without thinking up a name.
func (c *Config) NameFromHostname() {
	host, err := os.Hostname()
	if err != nil && host == "" {
		log.Fatal("Node name required and hostname not set. e.g. '-name=name'")
	}
	c.Name = host
}

func NewPeerServer(name string, path string, url string, bindAddr string, tlsConf *TLSConfig, tlsInfo *TLSInfo, registry *Registry, store store.Store, snapshotCount int, heartbeatTimeout, electionTimeout time.Duration) *PeerServer {
	s := &PeerServer{
		name:     name,
		url:      url,
		bindAddr: bindAddr,
		tlsConf:  tlsConf,
		tlsInfo:  tlsInfo,
		registry: registry,
		store:    store,
		followersStats: &raftFollowersStats{
			Leader:    name,
			Followers: make(map[string]*raftFollowerStats),
		},
		serverStats: &raftServerStats{
			Name:      name,
			StartTime: time.Now(),
			sendRateQueue: &statsQueue{
				back: -1,
			},
			recvRateQueue: &statsQueue{
				back: -1,
			},
		},
		HeartbeatTimeout: heartbeatTimeout,
		ElectionTimeout:  electionTimeout,

		timeoutThresholdChan: make(chan interface{}, 1),
	}

	// Create transporter for raft
	raftTransporter := newTransporter(tlsConf.Scheme, tlsConf.Client, s)

	// Create raft server
	raftServer, err := raft.NewServer(name, path, raftTransporter, s.store, s, "")
	if err != nil {
		log.Fatal(err)
	}

	s.snapConf = &snapshotConf{
		checkingInterval: time.Second * 3,
		// this is not accurate, we will update raft to provide an api
		lastIndex:   raftServer.CommitIndex(),
		snapshotThr: uint64(snapshotCount),
	}

	s.raftServer = raftServer
	s.raftServer.AddEventListener(raft.StateChangeEventType, s.raftEventLogger)
	s.raftServer.AddEventListener(raft.LeaderChangeEventType, s.raftEventLogger)
	s.raftServer.AddEventListener(raft.TermChangeEventType, s.raftEventLogger)
	s.raftServer.AddEventListener(raft.AddPeerEventType, s.raftEventLogger)
	s.raftServer.AddEventListener(raft.RemovePeerEventType, s.raftEventLogger)
	s.raftServer.AddEventListener(raft.HeartbeatTimeoutEventType, s.raftEventLogger)
	s.raftServer.AddEventListener(raft.ElectionTimeoutThresholdEventType, s.raftEventLogger)

	return s
}

// TLSServerConfig generates tls configuration based on TLSInfo
// If any error happens, this function will call log.Fatal
func TLSServerConfig(info *TLSInfo) *tls.Config {
	if info.KeyFile == "" || info.CertFile == "" {
		return nil
	}

	cfg, err := info.ServerConfig()
	if err != nil {
		log.Fatal("TLS info error: ", err)
	}
	return cfg
}

// NewListener creates a net.Listener
// If the given scheme is "https", it will generate TLS configuration based on TLSInfo.
// If any error happens, this function will call log.Fatal
func NewListener(scheme, addr string, tlsInfo *TLSInfo) net.Listener {
	if scheme == "https" {
		cfg, err := tlsInfo.ServerConfig()
		if err != nil {
			log.Fatal("TLS info error: ", err)
		}

		l, err := newTLSListener(addr, cfg)
		if err != nil {
			log.Fatal("Failed to create TLS listener: ", err)
		}
		return l
	}

	l, err := newListener(addr)
	if err != nil {
		log.Fatal("Failed to create listener: ", err)
	}
	return l
}

// profile starts CPU profiling.
func profile(path string) {
	f, err := os.Create(path)
	if err != nil {
		log.Fatal(err)
	}
	pprof.StartCPUProfile(f)

	c := make(chan os.Signal, 1)
	signal.Notify(c, os.Interrupt)
	go func() {
		sig := <-c
		log.Infof("captured %v, stopping profiler and exiting..", sig)
		pprof.StopCPUProfile()
		os.Exit(1)
	}()
}

func (s *PeerServer) joinCluster(cluster []string) bool {
	for _, peer := range cluster {
		if len(peer) == 0 {
			continue
		}

		err := s.joinByPeer(s.raftServer, peer, s.tlsConf.Scheme)
		if err == nil {
			log.Debugf("%s success join to the cluster via peer %s", s.name, peer)
			return true

		} else {
			if _, ok := err.(etcdErr.Error); ok {
				log.Fatal(err)
			}

			log.Debugf("cannot join to cluster via peer %s %s", peer, err)
		}
	}
	return false
}

func NewPeerServer(name string, path string, url string, bindAddr string, tlsConf *TLSConfig, tlsInfo *TLSInfo, registry *Registry, store store.Store, snapshotCount int) *PeerServer {
	s := &PeerServer{
		name:     name,
		url:      url,
		bindAddr: bindAddr,
		tlsConf:  tlsConf,
		tlsInfo:  tlsInfo,
		registry: registry,
		store:    store,
		snapConf: &snapshotConf{time.Second * 3, 0, uint64(snapshotCount)},
		followersStats: &raftFollowersStats{
			Leader:    name,
			Followers: make(map[string]*raftFollowerStats),
		},
		serverStats: &raftServerStats{
			StartTime: time.Now(),
			sendRateQueue: &statsQueue{
				back: -1,
			},
			recvRateQueue: &statsQueue{
				back: -1,
			},
		},
		HeartbeatTimeout: defaultHeartbeatTimeout,
		ElectionTimeout:  defaultElectionTimeout,
	}

	// Create transporter for raft
	raftTransporter := newTransporter(tlsConf.Scheme, tlsConf.Client, s)

	// Create raft server
	raftServer, err := raft.NewServer(name, path, raftTransporter, s.store, s, "")
	if err != nil {
		log.Fatal(err)
	}

	s.raftServer = raftServer

	return s
}

func (s *PeerServer) joinCluster(cluster []string) bool {
	for _, peer := range cluster {
		if len(peer) == 0 {
			continue
		}

		err := s.joinByPeer(s.raftServer, peer, s.Config.Scheme)
		if err == nil {
			log.Debugf("%s joined the cluster via peer %s", s.Config.Name, peer)
			return true

		}

		if _, ok := err.(etcdErr.Error); ok {
			log.Fatal(err)
		}

		log.Warnf("Attempt to join via %s failed: %s", peer, err)
	}

	return false
}

func main() {
	// Load configuration.
	var config = config.New()
	if err := config.Load(os.Args[1:]); err != nil {
		fmt.Println(server.Usage() + "\n")
		fmt.Println(err.Error() + "\n")
		os.Exit(1)
	} else if config.ShowVersion {
		fmt.Println("etcd version", server.ReleaseVersion)
		os.Exit(0)
	} else if config.ShowHelp {
		fmt.Println(server.Usage() + "\n")
		os.Exit(0)
	}

	// Enable options.
	if config.VeryVeryVerbose {
		log.Verbose = true
		raft.SetLogLevel(raft.Trace)
	} else if config.VeryVerbose {
		log.Verbose = true
		raft.SetLogLevel(raft.Debug)
	} else if config.Verbose {
		log.Verbose = true
	}
	if config.CPUProfileFile != "" {
		profile(config.CPUProfileFile)
	}

	if config.DataDir == "" {
		log.Fatal("The data dir was not set and could not be guessed from machine name")
	}

	// Create data directory if it doesn't already exist.
	if err := os.MkdirAll(config.DataDir, 0744); err != nil {
		log.Fatalf("Unable to create path: %s", err)
	}

	// Warn people if they have an info file
	info := filepath.Join(config.DataDir, "info")
	if _, err := os.Stat(info); err == nil {
		log.Warnf("All cached configuration is now ignored. The file %s can be removed.", info)
	}

	var mbName string
	if config.Trace() {
		mbName = config.MetricsBucketName()
		runtime.SetBlockProfileRate(1)
	}

	mb := metrics.NewBucket(mbName)

	if config.GraphiteHost != "" {
		err := mb.Publish(config.GraphiteHost)
		if err != nil {
			panic(err)
		}
	}

	// Retrieve CORS configuration
	corsInfo, err := ehttp.NewCORSInfo(config.CorsOrigins)
	if err != nil {
		log.Fatal("CORS:", err)
	}

	// Create etcd key-value store and registry.
	store := store.New()
	registry := server.NewRegistry(store)

	// Create stats objects
	followersStats := server.NewRaftFollowersStats(config.Name)
	serverStats := server.NewRaftServerStats(config.Name)

	// Calculate all of our timeouts
	heartbeatInterval := time.Duration(config.Peer.HeartbeatInterval) * time.Millisecond
	electionTimeout := time.Duration(config.Peer.ElectionTimeout) * time.Millisecond
	dialTimeout := (3 * heartbeatInterval) + electionTimeout
	responseHeaderTimeout := (3 * heartbeatInterval) + electionTimeout

	// Create peer server
	psConfig := server.PeerServerConfig{
		Name:           config.Name,
		Scheme:         config.PeerTLSInfo().Scheme(),
		URL:            config.Peer.Addr,
		SnapshotCount:  config.SnapshotCount,
		MaxClusterSize: config.MaxClusterSize,
		RetryTimes:     config.MaxRetryAttempts,
		RetryInterval:  config.RetryInterval,
	}
	ps := server.NewPeerServer(psConfig, registry, store, &mb, followersStats, serverStats)

	var psListener net.Listener
	if psConfig.Scheme == "https" {
		peerServerTLSConfig, err := config.PeerTLSInfo().ServerConfig()
		if err != nil {
			log.Fatal("peer server TLS error: ", err)
		}

		psListener, err = server.NewTLSListener(config.Peer.BindAddr, peerServerTLSConfig)
		if err != nil {
//.........这里部分代码省略.........

func main() {
	// Load configuration.
	var config = server.NewConfig()
	if err := config.Load(os.Args[1:]); err != nil {
		fmt.Println(server.Usage() + "\n")
		fmt.Println(err.Error() + "\n")
		os.Exit(1)
	} else if config.ShowVersion {
		fmt.Println(server.ReleaseVersion)
		os.Exit(0)
	} else if config.ShowHelp {
		fmt.Println(server.Usage() + "\n")
		os.Exit(0)
	}

	// Enable options.
	if config.VeryVeryVerbose {
		log.Verbose = true
		raft.SetLogLevel(raft.Trace)
	} else if config.VeryVerbose {
		log.Verbose = true
		raft.SetLogLevel(raft.Debug)
	} else if config.Verbose {
		log.Verbose = true
	}
	if config.CPUProfileFile != "" {
		profile(config.CPUProfileFile)
	}

	if config.DataDir == "" {
		log.Fatal("The data dir was not set and could not be guessed from machine name")
	}

	// Create data directory if it doesn't already exist.
	if err := os.MkdirAll(config.DataDir, 0744); err != nil {
		log.Fatalf("Unable to create path: %s", err)
	}

	// Load info object.
	info, err := config.Info()
	if err != nil {
		log.Fatal("info:", err)
	}

	// Retrieve TLS configuration.
	tlsConfig, err := info.EtcdTLS.Config()
	if err != nil {
		log.Fatal("Client TLS:", err)
	}
	peerTLSConfig, err := info.RaftTLS.Config()
	if err != nil {
		log.Fatal("Peer TLS:", err)
	}

	var mbName string
	if config.Trace() {
		mbName = config.MetricsBucketName()
		runtime.SetBlockProfileRate(1)
	}

	mb := metrics.NewBucket(mbName)

	if config.GraphiteHost != "" {
		err := mb.Publish(config.GraphiteHost)
		if err != nil {
			panic(err)
		}
	}

	// Create etcd key-value store and registry.
	store := store.New()
	registry := server.NewRegistry(store)

	// Create peer server.
	heartbeatTimeout := time.Duration(config.Peer.HeartbeatTimeout) * time.Millisecond
	electionTimeout := time.Duration(config.Peer.ElectionTimeout) * time.Millisecond
	ps := server.NewPeerServer(info.Name, config.DataDir, info.RaftURL, info.RaftListenHost, &peerTLSConfig, &info.RaftTLS, registry, store, config.SnapshotCount, heartbeatTimeout, electionTimeout, &mb)
	ps.MaxClusterSize = config.MaxClusterSize
	ps.RetryTimes = config.MaxRetryAttempts

	// Create client server.
	s := server.New(info.Name, info.EtcdURL, info.EtcdListenHost, &tlsConfig, &info.EtcdTLS, ps, registry, store, &mb)
	if err := s.AllowOrigins(config.CorsOrigins); err != nil {
		panic(err)
	}

	if config.Trace() {
		s.EnableTracing()
	}

	ps.SetServer(s)

	// Run peer server in separate thread while the client server blocks.
	go func() {
		log.Fatal(ps.ListenAndServe(config.Snapshot, config.Peers))
	}()
	log.Fatal(s.ListenAndServe())
}

func main() {
	// Load configuration.
	var config = server.NewConfig()
	if err := config.Load(os.Args[1:]); err != nil {
		fmt.Println(server.Usage() + "\n")
		fmt.Println(err.Error() + "\n")
		os.Exit(1)
	} else if config.ShowVersion {
		fmt.Println(server.ReleaseVersion)
		os.Exit(0)
	} else if config.ShowHelp {
		fmt.Println(server.Usage() + "\n")
		os.Exit(0)
	}

	// Enable options.
	if config.VeryVeryVerbose {
		log.Verbose = true
		raft.SetLogLevel(raft.Trace)
	} else if config.VeryVerbose {
		log.Verbose = true
		raft.SetLogLevel(raft.Debug)
	} else if config.Verbose {
		log.Verbose = true
	}
	if config.CPUProfileFile != "" {
		profile(config.CPUProfileFile)
	}

	if config.DataDir == "" {
		log.Fatal("The data dir was not set and could not be guessed from machine name")
	}

	// Create data directory if it doesn't already exist.
	if err := os.MkdirAll(config.DataDir, 0744); err != nil {
		log.Fatalf("Unable to create path: %s", err)
	}

	// Load info object.
	info, err := config.Info()
	if err != nil {
		log.Fatal("info:", err)
	}

	// Retrieve TLS configuration.
	tlsConfig, err := info.EtcdTLS.Config()
	if err != nil {
		log.Fatal("Client TLS:", err)
	}
	peerTLSConfig, err := info.RaftTLS.Config()
	if err != nil {
		log.Fatal("Peer TLS:", err)
	}

	var mbName string
	if config.Trace() {
		mbName = config.MetricsBucketName()
		runtime.SetBlockProfileRate(1)
	}

	mb := metrics.NewBucket(mbName)

	if config.GraphiteHost != "" {
		err := mb.Publish(config.GraphiteHost)
		if err != nil {
			panic(err)
		}
	}

	// Retrieve CORS configuration
	corsInfo, err := ehttp.NewCORSInfo(config.CorsOrigins)
	if err != nil {
		log.Fatal("CORS:", err)
	}

	// Create etcd key-value store and registry.
	store := store.New()
	registry := server.NewRegistry(store)

	// Create stats objects
	followersStats := server.NewRaftFollowersStats(info.Name)
	serverStats := server.NewRaftServerStats(info.Name)

	// Calculate all of our timeouts
	heartbeatTimeout := time.Duration(config.Peer.HeartbeatTimeout) * time.Millisecond
	electionTimeout := time.Duration(config.Peer.ElectionTimeout) * time.Millisecond
	dialTimeout := (3 * heartbeatTimeout) + electionTimeout
	responseHeaderTimeout := (3 * heartbeatTimeout) + electionTimeout

	// Create peer server.
	psConfig := server.PeerServerConfig{
		Name:           info.Name,
		Scheme:         peerTLSConfig.Scheme,
		URL:            info.RaftURL,
		SnapshotCount:  config.SnapshotCount,
		MaxClusterSize: config.MaxClusterSize,
		RetryTimes:     config.MaxRetryAttempts,
	}
	ps := server.NewPeerServer(psConfig, registry, store, &mb, followersStats, serverStats)

//.........这里部分代码省略.........

// Run the etcd instance.
func (e *Etcd) Run() {
	// Enable options.
	if e.Config.VeryVeryVerbose {
		log.Verbose = true
		raft.SetLogLevel(raft.Trace)
		goetcd.SetLogger(
			golog.New(
				"go-etcd",
				false,
				golog.CombinedSink(
					os.Stdout,
					"[%s] %s %-9s | %s\n",
					[]string{"prefix", "time", "priority", "message"},
				),
			),
		)
	} else if e.Config.VeryVerbose {
		log.Verbose = true
		raft.SetLogLevel(raft.Debug)
	} else if e.Config.Verbose {
		log.Verbose = true
	}

	if e.Config.CPUProfileFile != "" {
		profile(e.Config.CPUProfileFile)
	}

	if e.Config.DataDir == "" {
		log.Fatal("The data dir was not set and could not be guessed from machine name")
	}

	// Create data directory if it doesn't already exist.
	if err := os.MkdirAll(e.Config.DataDir, 0744); err != nil {
		log.Fatalf("Unable to create path: %s", err)
	}

	// Warn people if they have an info file
	info := filepath.Join(e.Config.DataDir, "info")
	if _, err := os.Stat(info); err == nil {
		log.Warnf("All cached configuration is now ignored. The file %s can be removed.", info)
	}

	var mbName string
	if e.Config.Trace() {
		mbName = e.Config.MetricsBucketName()
		runtime.SetBlockProfileRate(1)
	}

	mb := metrics.NewBucket(mbName)

	if e.Config.GraphiteHost != "" {
		err := mb.Publish(e.Config.GraphiteHost)
		if err != nil {
			panic(err)
		}
	}

	// Retrieve CORS configuration
	corsInfo, err := ehttp.NewCORSInfo(e.Config.CorsOrigins)
	if err != nil {
		log.Fatal("CORS:", err)
	}

	// Create etcd key-value store and registry.
	e.Store = store.New()
	e.Registry = server.NewRegistry(e.Store)

	// Create stats objects
	followersStats := server.NewRaftFollowersStats(e.Config.Name)
	serverStats := server.NewRaftServerStats(e.Config.Name)

	// Calculate all of our timeouts
	heartbeatInterval := time.Duration(e.Config.Peer.HeartbeatInterval) * time.Millisecond
	electionTimeout := time.Duration(e.Config.Peer.ElectionTimeout) * time.Millisecond
	dialTimeout := (3 * heartbeatInterval) + electionTimeout
	responseHeaderTimeout := (3 * heartbeatInterval) + electionTimeout

	// Create peer server
	psConfig := server.PeerServerConfig{
		Name:          e.Config.Name,
		Scheme:        e.Config.PeerTLSInfo().Scheme(),
		URL:           e.Config.Peer.Addr,
		SnapshotCount: e.Config.SnapshotCount,
		RetryTimes:    e.Config.MaxRetryAttempts,
		RetryInterval: e.Config.RetryInterval,
	}
	e.PeerServer = server.NewPeerServer(psConfig, e.Registry, e.Store, &mb, followersStats, serverStats)

	// Create raft transporter and server
	raftTransporter := server.NewTransporter(followersStats, serverStats, e.Registry, heartbeatInterval, dialTimeout, responseHeaderTimeout)
	if psConfig.Scheme == "https" {
		raftClientTLSConfig, err := e.Config.PeerTLSInfo().ClientConfig()
		if err != nil {
			log.Fatal("raft client TLS error: ", err)
		}
		raftTransporter.SetTLSConfig(*raftClientTLSConfig)
	}
	raftServer, err := raft.NewServer(e.Config.Name, e.Config.DataDir, raftTransporter, e.Store, e.PeerServer, "")
	if err != nil {
//.........这里部分代码省略.........

func main() {
	parseFlags()

	// Load configuration.
	var config = server.NewConfig()
	if err := config.Load(os.Args[1:]); err != nil {
		log.Fatal("Configuration error:", err)
	}

	// Turn on logging.
	if config.VeryVerbose {
		log.Verbose = true
		raft.SetLogLevel(raft.Debug)
	} else if config.Verbose {
		log.Verbose = true
	}

	// Setup a default directory based on the machine name
	if config.DataDir == "" {
		config.DataDir = config.Name + ".etcd"
		log.Warnf("Using the directory %s as the etcd configuration directory because a directory was not specified. ", config.DataDir)
	}

	// Create data directory if it doesn't already exist.
	if err := os.MkdirAll(config.DataDir, 0744); err != nil {
		log.Fatalf("Unable to create path: %s", err)
	}

	// Load info object.
	info, err := config.Info()
	if err != nil {
		log.Fatal("info:", err)
	}
	if info.Name == "" {
		host, err := os.Hostname()
		if err != nil || host == "" {
			log.Fatal("Machine name required and hostname not set. e.g. '-n=machine_name'")
		}
		log.Warnf("Using hostname %s as the machine name. You must ensure this name is unique among etcd machines.", host)
		info.Name = host
	}

	// Retrieve TLS configuration.
	tlsConfig, err := info.EtcdTLS.Config()
	if err != nil {
		log.Fatal("Client TLS:", err)
	}
	peerTLSConfig, err := info.RaftTLS.Config()
	if err != nil {
		log.Fatal("Peer TLS:", err)
	}

	// Create etcd key-value store and registry.
	store := store.New()
	registry := server.NewRegistry(store)

	// Create peer server.
	ps := server.NewPeerServer(info.Name, config.DataDir, info.RaftURL, info.RaftListenHost, &peerTLSConfig, &info.RaftTLS, registry, store, config.SnapCount)
	ps.MaxClusterSize = config.MaxClusterSize
	ps.RetryTimes = config.MaxRetryAttempts

	// Create client server.
	s := server.New(info.Name, info.EtcdURL, info.EtcdListenHost, &tlsConfig, &info.EtcdTLS, ps, registry, store)
	if err := s.AllowOrigins(config.Cors); err != nil {
		panic(err)
	}

	ps.SetServer(s)

	// Run peer server in separate thread while the client server blocks.
	go func() {
		log.Fatal(ps.ListenAndServe(config.Snapshot, config.Machines))
	}()
	log.Fatal(s.ListenAndServe())
}

// Run the etcd instance.
func (e *Etcd) Run() {
	// Sanitize all the input fields.
	if err := e.Config.Sanitize(); err != nil {
		log.Fatalf("failed sanitizing configuration: %v", err)
	}

	// Force remove server configuration if specified.
	if e.Config.Force {
		e.Config.Reset()
	}

	// Enable options.
	if e.Config.VeryVeryVerbose {
		log.Verbose = true
		raft.SetLogLevel(raft.Trace)
		goetcd.SetLogger(
			golog.New(
				"go-etcd",
				false,
				golog.CombinedSink(
					os.Stdout,
					"[%s] %s %-9s | %s\n",
					[]string{"prefix", "time", "priority", "message"},
				),
			),
		)
	} else if e.Config.VeryVerbose {
		log.Verbose = true
		raft.SetLogLevel(raft.Debug)
	} else if e.Config.Verbose {
		log.Verbose = true
	}

	if e.Config.CPUProfileFile != "" {
		profile(e.Config.CPUProfileFile)
	}

	if e.Config.DataDir == "" {
		log.Fatal("The data dir was not set and could not be guessed from machine name")
	}

	// Create data directory if it doesn't already exist.
	if err := os.MkdirAll(e.Config.DataDir, 0744); err != nil {
		log.Fatalf("Unable to create path: %s", err)
	}

	// Warn people if they have an info file
	info := filepath.Join(e.Config.DataDir, "info")
	if _, err := os.Stat(info); err == nil {
		log.Warnf("All cached configuration is now ignored. The file %s can be removed.", info)
	}

	var mbName string
	if e.Config.Trace() {
		mbName = e.Config.MetricsBucketName()
		runtime.SetBlockProfileRate(1)
	}

	mb := metrics.NewBucket(mbName)

	if e.Config.GraphiteHost != "" {
		err := mb.Publish(e.Config.GraphiteHost)
		if err != nil {
			panic(err)
		}
	}

	// Retrieve CORS configuration
	corsInfo, err := ehttp.NewCORSInfo(e.Config.CorsOrigins)
	if err != nil {
		log.Fatal("CORS:", err)
	}

	// Create etcd key-value store and registry.
	e.Store = store.New()
	e.Registry = server.NewRegistry(e.Store)

	// Create stats objects
	followersStats := server.NewRaftFollowersStats(e.Config.Name)
	serverStats := server.NewRaftServerStats(e.Config.Name)

	// Calculate all of our timeouts
	heartbeatInterval := time.Duration(e.Config.Peer.HeartbeatInterval) * time.Millisecond
	electionTimeout := time.Duration(e.Config.Peer.ElectionTimeout) * time.Millisecond
	dialTimeout := (3 * heartbeatInterval) + electionTimeout
	responseHeaderTimeout := (3 * heartbeatInterval) + electionTimeout

	clientTransporter := &httpclient.Transport{
		ResponseHeaderTimeout: responseHeaderTimeout + extraTimeout,
		// This is a workaround for Transport.CancelRequest doesn't work on
		// HTTPS connections blocked. The patch for it is in progress,
		// and would be available in Go1.3
		// More: https://codereview.appspot.com/69280043/
		ConnectTimeout: dialTimeout + extraTimeout,
		RequestTimeout: responseHeaderTimeout + dialTimeout + 2*extraTimeout,
	}
	if e.Config.PeerTLSInfo().Scheme() == "https" {
		clientTLSConfig, err := e.Config.PeerTLSInfo().ClientConfig()
		if err != nil {
//.........这里部分代码省略.........

// Try all possible ways to find clusters to join
// Include log data in -data-dir, -discovery and -peers
//
// Peer discovery follows this order:
// 1. previous peers in -data-dir
// 2. -discovery
// 3. -peers
//
// TODO(yichengq): RaftServer should be started as late as possible.
// Current implementation to start it is not that good,
// and should be refactored later.
func (s *PeerServer) findCluster(discoverURL string, peers []string) {
	name := s.Config.Name
	isNewNode := s.raftServer.IsLogEmpty()

	// Try its best to find possible peers, and connect with them.
	if !isNewNode {
		// It is not allowed to join the cluster with existing peer address
		// This prevents old node joining with different name by mistake.
		if !s.checkPeerAddressNonconflict() {
			log.Fatalf("%v is not allowed to join the cluster with existing URL %v", s.Config.Name, s.Config.URL)
		}

		// Take old nodes into account.
		allPeers := s.getKnownPeers()
		// Discover registered peers.
		// TODO(yichengq): It may mess up discoverURL if this is
		// set wrong by mistake. This may need to refactor discovery
		// module. Fix it later.
		if discoverURL != "" {
			discoverPeers, _ := s.handleDiscovery(discoverURL)
			allPeers = append(allPeers, discoverPeers...)
		}
		allPeers = append(allPeers, peers...)
		allPeers = s.removeSelfFromList(allPeers)

		// If there is possible peer list, use it to find cluster.
		if len(allPeers) > 0 {
			// TODO(yichengq): joinCluster may fail if there's no leader for
			// current cluster. It should wait if the cluster is under
			// leader election, or the node with changed IP cannot join
			// the cluster then.
			if err := s.startAsFollower(allPeers, 1); err == nil {
				log.Debugf("%s joins to the previous cluster %v", name, allPeers)
				return
			}

			log.Warnf("%s cannot connect to previous cluster %v", name, allPeers)
		}

		// TODO(yichengq): Think about the action that should be done
		// if it cannot connect any of the previous known node.
		s.raftServer.Start()
		log.Debugf("%s is restarting the cluster %v", name, allPeers)
		return
	}

	// Attempt cluster discovery
	if discoverURL != "" {
		discoverPeers, discoverErr := s.handleDiscovery(discoverURL)
		// It is registered in discover url
		if discoverErr == nil {
			// start as a leader in a new cluster
			if len(discoverPeers) == 0 {
				log.Debugf("%s is starting a new cluster via discover service", name)
				s.startAsLeader()
			} else {
				log.Debugf("%s is joining a cluster %v via discover service", name, discoverPeers)
				if err := s.startAsFollower(discoverPeers, s.Config.RetryTimes); err != nil {
					log.Fatal(err)
				}
			}
			return
		}
		log.Warnf("%s failed to connect discovery service[%v]: %v", name, discoverURL, discoverErr)

		if len(peers) == 0 {
			log.Fatalf("%s, the new leader, must register itself to discovery service as required", name)
		}
	}

	if len(peers) > 0 {
		if err := s.startAsFollower(peers, s.Config.RetryTimes); err != nil {
			log.Fatalf("%s cannot connect to existing cluster %v", name, peers)
		}
		return
	}

	log.Infof("%s is starting a new cluster.", s.Config.Name)
	s.startAsLeader()
	return
}