func NewClusterServer(s *etcdserver.EtcdServer) *ClusterServer {
	return &ClusterServer{
		cluster:   s.Cluster(),
		server:    s,
		raftTimer: s,
	}
}

func newStreamInterceptor(s *etcdserver.EtcdServer) grpc.StreamServerInterceptor {
	smap := monitorLeader(s)

	return func(srv interface{}, ss grpc.ServerStream, info *grpc.StreamServerInfo, handler grpc.StreamHandler) error {
		if !api.IsCapabilityEnabled(api.V3rpcCapability) {
			return rpctypes.ErrGRPCNotCapable
		}

		md, ok := metadata.FromContext(ss.Context())
		if ok {
			if ks := md[rpctypes.MetadataRequireLeaderKey]; len(ks) > 0 && ks[0] == rpctypes.MetadataHasLeader {
				if s.Leader() == types.ID(raft.None) {
					return rpctypes.ErrGRPCNoLeader
				}

				cctx, cancel := context.WithCancel(ss.Context())
				ss = serverStreamWithCtx{ctx: cctx, cancel: &cancel, ServerStream: ss}

				smap.mu.Lock()
				smap.streams[ss] = struct{}{}
				smap.mu.Unlock()

				defer func() {
					smap.mu.Lock()
					delete(smap.streams, ss)
					smap.mu.Unlock()
					cancel()
				}()

			}
		}
		return metricsStreamInterceptor(srv, ss, info, handler)
	}
}

func NewKVServer(s *etcdserver.EtcdServer) pb.KVServer {
	return &kvServer{
		clusterID: int64(s.Cluster().ID()),
		memberID:  int64(s.ID()),
		raftTimer: s,
		kv:        s,
	}
}

// NewClientHandler generates a muxed http.Handler with the given parameters to serve etcd client requests.
func NewClientHandler(server *etcdserver.EtcdServer, timeout time.Duration) http.Handler {
	sec := auth.NewStore(server, timeout)

	kh := &keysHandler{
		sec:                   sec,
		server:                server,
		cluster:               server.Cluster(),
		timer:                 server,
		timeout:               timeout,
		clientCertAuthEnabled: server.Cfg.ClientCertAuthEnabled,
	}

	sh := &statsHandler{
		stats: server,
	}

	mh := &membersHandler{
		sec:     sec,
		server:  server,
		cluster: server.Cluster(),
		timeout: timeout,
		clock:   clockwork.NewRealClock(),
		clientCertAuthEnabled: server.Cfg.ClientCertAuthEnabled,
	}

	dmh := &deprecatedMachinesHandler{
		cluster: server.Cluster(),
	}

	sech := &authHandler{
		sec:                   sec,
		cluster:               server.Cluster(),
		clientCertAuthEnabled: server.Cfg.ClientCertAuthEnabled,
	}

	mux := http.NewServeMux()
	mux.HandleFunc("/", http.NotFound)
	mux.Handle(healthPath, healthHandler(server))
	mux.HandleFunc(versionPath, versionHandler(server.Cluster(), serveVersion))
	mux.Handle(keysPrefix, kh)
	mux.Handle(keysPrefix+"/", kh)
	mux.HandleFunc(statsPrefix+"/store", sh.serveStore)
	mux.HandleFunc(statsPrefix+"/self", sh.serveSelf)
	mux.HandleFunc(statsPrefix+"/leader", sh.serveLeader)
	mux.HandleFunc(varsPath, serveVars)
	mux.HandleFunc(configPath+"/local/log", logHandleFunc)
	mux.Handle(metricsPath, prometheus.Handler())
	mux.Handle(membersPrefix, mh)
	mux.Handle(membersPrefix+"/", mh)
	mux.Handle(deprecatedMachinesPrefix, dmh)
	handleAuth(mux, sech)

	return requestLogger(mux)
}

// NewPeerHandler generates an http.Handler to handle etcd peer (raft) requests.
func NewPeerHandler(server *etcdserver.EtcdServer) http.Handler {
	mh := &peerMembersHandler{
		clusterInfo: server.Cluster,
	}

	mux := http.NewServeMux()
	mux.HandleFunc("/", http.NotFound)
	mux.Handle(rafthttp.RaftPrefix, server.RaftHandler())
	mux.Handle(rafthttp.RaftPrefix+"/", server.RaftHandler())
	mux.Handle(peerMembersPrefix, mh)
	return mux
}

// NewPeerHandler generates an http.Handler to handle etcd peer (raft) requests.
func NewPeerHandler(server *etcdserver.EtcdServer) http.Handler {
	rh := rafthttp.NewHandler(server, server.Cluster.ID())
	rsh := rafthttp.NewStreamHandler(server.SenderFinder(), server.ID(), server.Cluster.ID())
	mh := &peerMembersHandler{
		clusterInfo: server.Cluster,
	}

	mux := http.NewServeMux()
	mux.HandleFunc("/", http.NotFound)
	mux.Handle(rafthttp.RaftPrefix, rh)
	mux.Handle(rafthttp.RaftStreamPrefix+"/", rsh)
	mux.Handle(peerMembersPrefix, mh)
	return mux
}

func newUnaryInterceptor(s *etcdserver.EtcdServer) grpc.UnaryServerInterceptor {
	return func(ctx context.Context, req interface{}, info *grpc.UnaryServerInfo, handler grpc.UnaryHandler) (resp interface{}, err error) {
		if !api.IsCapabilityEnabled(api.V3rpcCapability) {
			return nil, rpctypes.ErrGRPCNotCapable
		}

		md, ok := metadata.FromContext(ctx)
		if ok {
			if ks := md[rpctypes.MetadataRequireLeaderKey]; len(ks) > 0 && ks[0] == rpctypes.MetadataHasLeader {
				if s.Leader() == types.ID(raft.None) {
					return nil, rpctypes.ErrGRPCNoLeader
				}
			}
		}
		return metricsUnaryInterceptor(ctx, req, info, handler)
	}
}

// NewPeerHandler generates an http.Handler to handle etcd peer requests.
func NewPeerHandler(s *etcdserver.EtcdServer) http.Handler {
	var lh http.Handler
	if l := s.Lessor(); l != nil {
		lh = lease.NewHandler(l)
	}
	return newPeerHandler(s.Cluster(), s.RaftHandler(), lh)
}

// serve accepts incoming connections on the listener l,
// creating a new service goroutine for each. The service goroutines
// read requests and then call handler to reply to them.
func serve(sctx *serveCtx, s *etcdserver.EtcdServer, tlscfg *tls.Config, handler http.Handler) error {
	logger := defaultLog.New(ioutil.Discard, "etcdhttp", 0)

	<-s.ReadyNotify()
	plog.Info("ready to serve client requests")

	m := cmux.New(sctx.l)

	if sctx.insecure {
		gs := v3rpc.Server(s, nil)
		grpcl := m.Match(cmux.HTTP2())
		go func() { plog.Fatal(gs.Serve(grpcl)) }()

		srvhttp := &http.Server{
			Handler:  handler,
			ErrorLog: logger, // do not log user error
		}
		httpl := m.Match(cmux.HTTP1())
		go func() { plog.Fatal(srvhttp.Serve(httpl)) }()
		plog.Noticef("serving insecure client requests on %s, this is strongly discouraged!", sctx.host)
	}

	if sctx.secure {
		gs := v3rpc.Server(s, tlscfg)
		handler = grpcHandlerFunc(gs, handler)

		tlsl := tls.NewListener(m.Match(cmux.Any()), tlscfg)
		// TODO: add debug flag; enable logging when debug flag is set
		srv := &http.Server{
			Handler:   handler,
			TLSConfig: tlscfg,
			ErrorLog:  logger, // do not log user error
		}
		go func() { plog.Fatal(srv.Serve(tlsl)) }()

		plog.Infof("serving client requests on %s", sctx.host)
	}

	return m.Serve()
}

// TODO: change etcdserver to raft interface when we have it.
//       add test for healthHandler when we have the interface ready.
func healthHandler(server *etcdserver.EtcdServer) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		if !allowMethod(w, r.Method, "GET") {
			return
		}

		if uint64(server.Leader()) == raft.None {
			http.Error(w, `{"health": "false"}`, http.StatusServiceUnavailable)
			return
		}

		// wait for raft's progress
		index := server.Index()
		for i := 0; i < 3; i++ {
			time.Sleep(250 * time.Millisecond)
			if server.Index() > index {
				w.WriteHeader(http.StatusOK)
				w.Write([]byte(`{"health": "true"}`))
				return
			}
		}

		http.Error(w, `{"health": "false"}`, http.StatusServiceUnavailable)
		return
	}
}

func monitorLeader(s *etcdserver.EtcdServer) *streamsMap {
	smap := &streamsMap{
		streams: make(map[grpc.ServerStream]struct{}),
	}

	go func() {
		election := time.Duration(s.Cfg.TickMs) * time.Duration(s.Cfg.ElectionTicks) * time.Millisecond
		noLeaderCnt := 0

		for {
			select {
			case <-s.StopNotify():
				return
			case <-time.After(election):
				if s.Leader() == types.ID(raft.None) {
					noLeaderCnt++
				} else {
					noLeaderCnt = 0
				}

				// We are more conservative on canceling existing streams. Reconnecting streams
				// cost much more than just rejecting new requests. So we wait until the member
				// cannot find a leader for maxNoLeaderCnt election timeouts to cancel existing streams.
				if noLeaderCnt >= maxNoLeaderCnt {
					smap.mu.Lock()
					for ss := range smap.streams {
						if ssWithCtx, ok := ss.(serverStreamWithCtx); ok {
							(*ssWithCtx.cancel)()
							<-ss.Context().Done()
						}
					}
					smap.streams = make(map[grpc.ServerStream]struct{})
					smap.mu.Unlock()
				}
			}
		}
	}()

	return smap
}

// capabilityLoop checks the cluster version every 500ms and updates
// the enabledMap when the cluster version increased.
// capabilityLoop MUST be ran in a goroutine before checking capability
// or using capabilityHandler.
func capabilityLoop(s *etcdserver.EtcdServer) {
	stopped := s.StopNotify()

	var pv *semver.Version
	for {
		if v := s.ClusterVersion(); v != pv {
			if pv == nil || (v != nil && pv.LessThan(*v)) {
				pv = v
				enableMapMu.Lock()
				enabledMap = capabilityMaps[pv.String()]
				enableMapMu.Unlock()
				plog.Infof("enabled capabilities for version %s", pv)
			}
		}

		select {
		case <-stopped:
			return
		case <-time.After(500 * time.Millisecond):
		}
	}
}

func NewWatchServer(s *etcdserver.EtcdServer) pb.WatchServer {
	return &watchServer{
		clusterID: int64(s.Cluster().ID()),
		memberID:  int64(s.ID()),
		raftTimer: s,
		watchable: s.Watchable(),
	}
}

func newHeader(s *etcdserver.EtcdServer) header {
	return header{
		clusterID: int64(s.Cluster().ID()),
		memberID:  int64(s.ID()),
		raftTimer: s,
		rev:       func() int64 { return s.KV().Rev() },
	}
}

// serve accepts incoming connections on the listener l,
// creating a new service goroutine for each. The service goroutines
// read requests and then call handler to reply to them.
func serve(sctx *serveCtx, s *etcdserver.EtcdServer, tlscfg *tls.Config, handler http.Handler) error {
	logger := defaultLog.New(ioutil.Discard, "etcdhttp", 0)

	<-s.ReadyNotify()
	plog.Info("ready to serve client requests")

	m := cmux.New(sctx.l)

	if sctx.insecure {
		gs := v3rpc.Server(s, nil)
		grpcl := m.Match(cmux.HTTP2())
		go func() { plog.Fatal(gs.Serve(grpcl)) }()

		opts := []grpc.DialOption{
			grpc.WithInsecure(),
		}
		gwmux, err := registerGateway(sctx.l.Addr().String(), opts)
		if err != nil {
			return err
		}

		httpmux := http.NewServeMux()
		httpmux.Handle("/v3alpha/", gwmux)
		httpmux.Handle("/", handler)
		srvhttp := &http.Server{
			Handler:  httpmux,
			ErrorLog: logger, // do not log user error
		}
		httpl := m.Match(cmux.HTTP1())
		go func() { plog.Fatal(srvhttp.Serve(httpl)) }()
		plog.Noticef("serving insecure client requests on %s, this is strongly discouraged!", sctx.host)
	}

	if sctx.secure {
		gs := v3rpc.Server(s, tlscfg)
		handler = grpcHandlerFunc(gs, handler)

		dtls := *tlscfg
		// trust local server
		dtls.InsecureSkipVerify = true
		creds := credentials.NewTLS(&dtls)
		opts := []grpc.DialOption{grpc.WithTransportCredentials(creds)}
		gwmux, err := registerGateway(sctx.l.Addr().String(), opts)
		if err != nil {
			return err
		}

		tlsl := tls.NewListener(m.Match(cmux.Any()), tlscfg)
		// TODO: add debug flag; enable logging when debug flag is set
		httpmux := http.NewServeMux()
		httpmux.Handle("/v3alpha/", gwmux)
		httpmux.Handle("/", handler)
		srv := &http.Server{
			Handler:   httpmux,
			TLSConfig: tlscfg,
			ErrorLog:  logger, // do not log user error
		}
		go func() { plog.Fatal(srv.Serve(tlsl)) }()

		plog.Infof("serving client requests on %s", sctx.host)
	}

	return m.Serve()
}

//.........这里部分代码省略.........
		if sctxs[u.Host] != nil {
			if ctx.secure {
				sctxs[u.Host].secure = true
			}
			if ctx.insecure {
				sctxs[u.Host].insecure = true
			}
			continue
		}

		var l net.Listener

		l, err = net.Listen("tcp", u.Host)
		if err != nil {
			return nil, err
		}

		var fdLimit uint64
		if fdLimit, err = runtimeutil.FDLimit(); err == nil {
			if fdLimit <= reservedInternalFDNum {
				plog.Fatalf("file descriptor limit[%d] of etcd process is too low, and should be set higher than %d to ensure internal usage", fdLimit, reservedInternalFDNum)
			}
			l = transport.LimitListener(l, int(fdLimit-reservedInternalFDNum))
		}

		l, err = transport.NewKeepAliveListener(l, "tcp", nil)
		ctx.l = l
		if err != nil {
			return nil, err
		}

		plog.Info("listening for client requests on ", u.Host)
		defer func() {
			if err != nil {
				l.Close()
				plog.Info("stopping listening for client requests on ", u.Host)
			}
		}()
		sctxs[u.Host] = ctx
	}

	//载入服务器相关配置
	srvcfg := &etcdserver.ServerConfig{
		Name:                    cfg.name,            //etcd服务名
		ClientURLs:              cfg.acurls,          //其他etcd监听型号地址(一般为其他主机或其他端口) (同步与交互etcd信息)
		PeerURLs:                cfg.apurls,          //监听信号地址(本机端口) (同步与交互etcd信息)
		DataDir:                 cfg.dir,             //数据通信保存位置 (默认产生的文件夹 member/snap member/wal)
		DedicatedWALDir:         cfg.walDir,          //ETCD将写WAL文件到walDir而不是DATADIR。这允许使用一个专用磁盘 并有助于避免记录和其它IO操作之间io的竞争。 默认为空 写入DataDir
		SnapCount:               cfg.snapCount,       //提交的事务数来触发快照到磁盘 默认为10000
		MaxSnapFiles:            cfg.maxSnapFiles,    //快照文件保留最大数量（0为无限制）默认值：5 windows为:0
		MaxWALFiles:             cfg.maxWalFiles,     //wal文件保留最大数量（0为无限制）默认值：5 windows为:0
		InitialPeerURLsMap:      urlsmap,             //其他etcd监听型号地址
		InitialClusterToken:     token,               //通信认证用
		DiscoveryURL:            cfg.durl,            //动态发现协议的url
		DiscoveryProxy:          cfg.dproxy,          //动态发现协议(HTTP代理)
		NewCluster:              cfg.isNewCluster(),  //是否为新建集群
		ForceNewCluster:         cfg.forceNewCluster, //--???--
		PeerTLSInfo:             cfg.peerTLSInfo,     //加密文本传输协议基本信息
		TickMs:                  cfg.TickMs,          //心跳间隔的时间（毫秒）。
		ElectionTicks:           cfg.electionTicks(), //时间（毫秒）选举超时
		AutoCompactionRetention: cfg.autoCompactionRetention,
		StrictReconfigCheck:     cfg.strictReconfigCheck, //严格配置检查 默认为false
		EnablePprof:             cfg.enablePprof,         //启用通过HTTP服务器运行时分析数据。地址是在客户端的URL+“/debug/ pprof”
	}

	//启动服务
	var s *etcdserver.EtcdServer
	s, err = etcdserver.NewServer(srvcfg)
	if err != nil {
		return nil, err
	}
	s.Start()
	osutil.RegisterInterruptHandler(s.Stop)

	if cfg.corsInfo.String() != "" {
		plog.Infof("cors = %s", cfg.corsInfo)
	}
	ch := http.Handler(&cors.CORSHandler{
		Handler: etcdhttp.NewClientHandler(s, srvcfg.ReqTimeout()),
		Info:    cfg.corsInfo,
	})
	ph := etcdhttp.NewPeerHandler(s)

	// Start the peer server in a goroutine
	for _, l := range plns {
		go func(l net.Listener) {
			plog.Fatal(servePeerHTTP(l, ph))
		}(l)
	}
	// Start a client server goroutine for each listen address
	for _, sctx := range sctxs {
		go func(sctx *serveCtx) {
			// read timeout does not work with http close notify
			// TODO: https://github.com/golang/go/issues/9524
			plog.Fatal(serve(sctx, s, ctlscfg, ch))
		}(sctx)
	}

	return s.StopNotify(), nil
}

func NewQuotaLeaseServer(s *etcdserver.EtcdServer) pb.LeaseServer {
	return &quotaLeaseServer{
		NewLeaseServer(s),
		quotaAlarmer{etcdserver.NewBackendQuota(s), s, s.ID()},
	}
}

// NewClientHandler generates a muxed http.Handler with the given parameters to serve etcd client requests.
func NewClientHandler(server *etcdserver.EtcdServer, timeout time.Duration) http.Handler {
	go capabilityLoop(server)

	sec := auth.NewStore(server, timeout)

	kh := &keysHandler{
		sec:     sec,
		server:  server,
		cluster: server.Cluster(),
		timer:   server,
		timeout: timeout,
	}

	sh := &statsHandler{
		stats: server,
	}

	mh := &membersHandler{
		sec:     sec,
		server:  server,
		cluster: server.Cluster(),
		timeout: timeout,
		clock:   clockwork.NewRealClock(),
	}

	dmh := &deprecatedMachinesHandler{
		cluster: server.Cluster(),
	}

	sech := &authHandler{
		sec:     sec,
		cluster: server.Cluster(),
	}

	mux := http.NewServeMux()
	mux.HandleFunc("/", http.NotFound)
	mux.Handle(healthPath, healthHandler(server))
	mux.HandleFunc(versionPath, versionHandler(server.Cluster(), serveVersion))
	mux.Handle(keysPrefix, kh)
	mux.Handle(keysPrefix+"/", kh)
	mux.HandleFunc(statsPrefix+"/store", sh.serveStore)
	mux.HandleFunc(statsPrefix+"/self", sh.serveSelf)
	mux.HandleFunc(statsPrefix+"/leader", sh.serveLeader)
	mux.HandleFunc(varsPath, serveVars)
	mux.HandleFunc(configPath+"/local/log", logHandleFunc)
	mux.Handle(metricsPath, prometheus.Handler())
	mux.Handle(membersPrefix, mh)
	mux.Handle(membersPrefix+"/", mh)
	mux.Handle(deprecatedMachinesPrefix, dmh)
	handleAuth(mux, sech)

	if server.IsPprofEnabled() {
		plog.Infof("pprof is enabled under %s", pprofPrefix)

		mux.HandleFunc(pprofPrefix, pprof.Index)
		mux.HandleFunc(pprofPrefix+"/profile", pprof.Profile)
		mux.HandleFunc(pprofPrefix+"/symbol", pprof.Symbol)
		mux.HandleFunc(pprofPrefix+"/cmdline", pprof.Cmdline)
		// TODO: currently, we don't create an entry for pprof.Trace,
		// because go 1.4 doesn't provide it. After support of go 1.4 is dropped,
		// we should add the entry.

		mux.Handle(pprofPrefix+"/heap", pprof.Handler("heap"))
		mux.Handle(pprofPrefix+"/goroutine", pprof.Handler("goroutine"))
		mux.Handle(pprofPrefix+"/threadcreate", pprof.Handler("threadcreate"))
		mux.Handle(pprofPrefix+"/block", pprof.Handler("block"))
	}

	return requestLogger(mux)
}

// startEtcd launches the etcd server and HTTP handlers for client/server communication.
func startEtcd(cfg *config) (<-chan struct{}, error) {
	urlsmap, token, err := getPeerURLsMapAndToken(cfg)
	if err != nil {
		return nil, fmt.Errorf("error setting up initial cluster: %v", err)
	}

	pt, err := transport.NewTimeoutTransport(cfg.peerTLSInfo, rafthttp.DialTimeout, rafthttp.ConnReadTimeout, rafthttp.ConnWriteTimeout)
	if err != nil {
		return nil, err
	}

	if !cfg.peerTLSInfo.Empty() {
		plog.Infof("peerTLS: %s", cfg.peerTLSInfo)
	}
	plns := make([]net.Listener, 0)
	for _, u := range cfg.lpurls {
		var l net.Listener
		l, err = transport.NewTimeoutListener(u.Host, u.Scheme, cfg.peerTLSInfo, rafthttp.ConnReadTimeout, rafthttp.ConnWriteTimeout)
		if err != nil {
			return nil, err
		}

		urlStr := u.String()
		plog.Info("listening for peers on ", urlStr)
		defer func() {
			if err != nil {
				l.Close()
				plog.Info("stopping listening for peers on ", urlStr)
			}
		}()
		plns = append(plns, l)
	}

	if !cfg.clientTLSInfo.Empty() {
		plog.Infof("clientTLS: %s", cfg.clientTLSInfo)
	}
	clns := make([]net.Listener, 0)
	for _, u := range cfg.lcurls {
		var l net.Listener
		l, err = transport.NewKeepAliveListener(u.Host, u.Scheme, cfg.clientTLSInfo)
		if err != nil {
			return nil, err
		}

		urlStr := u.String()
		plog.Info("listening for client requests on ", urlStr)
		defer func() {
			if err != nil {
				l.Close()
				plog.Info("stopping listening for client requests on ", urlStr)
			}
		}()
		clns = append(clns, l)
	}

	srvcfg := &etcdserver.ServerConfig{
		Name:                cfg.name,
		ClientURLs:          cfg.acurls,
		PeerURLs:            cfg.apurls,
		DataDir:             cfg.dir,
		SnapCount:           cfg.snapCount,
		MaxSnapFiles:        cfg.maxSnapFiles,
		MaxWALFiles:         cfg.maxWalFiles,
		InitialPeerURLsMap:  urlsmap,
		InitialClusterToken: token,
		DiscoveryURL:        cfg.durl,
		DiscoveryProxy:      cfg.dproxy,
		NewCluster:          cfg.isNewCluster(),
		ForceNewCluster:     cfg.forceNewCluster,
		Transport:           pt,
		TickMs:              cfg.TickMs,
		ElectionTicks:       cfg.electionTicks(),
	}
	var s *etcdserver.EtcdServer
	s, err = etcdserver.NewServer(srvcfg)
	if err != nil {
		return nil, err
	}
	s.Start()
	osutil.RegisterInterruptHandler(s.Stop)

	if cfg.corsInfo.String() != "" {
		plog.Infof("cors = %s", cfg.corsInfo)
	}
	ch := &cors.CORSHandler{
		Handler: etcdhttp.NewClientHandler(s),
		Info:    cfg.corsInfo,
	}
	ph := etcdhttp.NewPeerHandler(s.Cluster(), s.RaftHandler())
	// Start the peer server in a goroutine
	for _, l := range plns {
		go func(l net.Listener) {
			plog.Fatal(serveHTTP(l, ph, 5*time.Minute))
		}(l)
	}
	// Start a client server goroutine for each listen address
	for _, l := range clns {
		go func(l net.Listener) {
			// read timeout does not work with http close notify
//.........这里部分代码省略.........

// startEtcd launches the etcd server and HTTP handlers for client/server communication.
func startEtcd(cfg *config) (<-chan struct{}, error) {
	cls, err := setupCluster(cfg)
	if err != nil {
		return nil, fmt.Errorf("error setting up initial cluster: %v", err)
	}

	if cfg.dir == "" {
		cfg.dir = fmt.Sprintf("%v.etcd", cfg.name)
		log.Printf("no data-dir provided, using default data-dir ./%s", cfg.dir)
	}
	if err := makeMemberDir(cfg.dir); err != nil {
		return nil, fmt.Errorf("cannot use /member sub-directory: %v", err)
	}
	membdir := path.Join(cfg.dir, "member")
	if err := fileutil.IsDirWriteable(membdir); err != nil {
		return nil, fmt.Errorf("cannot write to data directory: %v", err)
	}

	pt, err := transport.NewTimeoutTransport(cfg.peerTLSInfo, rafthttp.ConnReadTimeout, rafthttp.ConnWriteTimeout)
	if err != nil {
		return nil, err
	}

	if !cfg.peerTLSInfo.Empty() {
		log.Printf("etcd: peerTLS: %s", cfg.peerTLSInfo)
	}
	plns := make([]net.Listener, 0)
	for _, u := range cfg.lpurls {
		var l net.Listener
		l, err = transport.NewTimeoutListener(u.Host, u.Scheme, cfg.peerTLSInfo, rafthttp.ConnReadTimeout, rafthttp.ConnWriteTimeout)
		if err != nil {
			return nil, err
		}

		urlStr := u.String()
		log.Print("etcd: listening for peers on ", urlStr)
		defer func() {
			if err != nil {
				l.Close()
				log.Print("etcd: stopping listening for peers on ", urlStr)
			}
		}()
		plns = append(plns, l)
	}

	if !cfg.clientTLSInfo.Empty() {
		log.Printf("etcd: clientTLS: %s", cfg.clientTLSInfo)
	}
	clns := make([]net.Listener, 0)
	for _, u := range cfg.lcurls {
		var l net.Listener
		l, err = transport.NewKeepAliveListener(u.Host, u.Scheme, cfg.clientTLSInfo)
		if err != nil {
			return nil, err
		}

		urlStr := u.String()
		log.Print("etcd: listening for client requests on ", urlStr)
		defer func() {
			if err != nil {
				l.Close()
				log.Print("etcd: stopping listening for client requests on ", urlStr)
			}
		}()
		clns = append(clns, l)
	}

	srvcfg := &etcdserver.ServerConfig{
		Name:            cfg.name,
		ClientURLs:      cfg.acurls,
		PeerURLs:        cfg.apurls,
		DataDir:         membdir,
		SnapCount:       cfg.snapCount,
		MaxSnapFiles:    cfg.maxSnapFiles,
		MaxWALFiles:     cfg.maxWalFiles,
		Cluster:         cls,
		DiscoveryURL:    cfg.durl,
		DiscoveryProxy:  cfg.dproxy,
		NewCluster:      cfg.isNewCluster(),
		ForceNewCluster: cfg.forceNewCluster,
		Transport:       pt,
		TickMs:          cfg.TickMs,
		ElectionTicks:   cfg.electionTicks(),
	}
	var s *etcdserver.EtcdServer
	s, err = etcdserver.NewServer(srvcfg)
	if err != nil {
		return nil, err
	}
	s.Start()

	if cfg.corsInfo.String() != "" {
		log.Printf("etcd: cors = %s", cfg.corsInfo)
	}
	ch := &cors.CORSHandler{
		Handler: etcdhttp.NewClientHandler(s),
		Info:    cfg.corsInfo,
	}
	ph := etcdhttp.NewPeerHandler(s.Cluster, s.RaftHandler())
//.........这里部分代码省略.........