// setupCluster sets up the cluster definition for bootstrap or discovery.
func setupCluster() (*etcdserver.Cluster, error) {
	set := make(map[string]bool)
	fs.Visit(func(f *flag.Flag) {
		set[f.Name] = true
	})
	if set["discovery"] && set["initial-cluster"] {
		return nil, fmt.Errorf("both discovery and bootstrap-config are set")
	}
	apurls, err := flags.URLsFromFlags(fs, "initial-advertise-peer-urls", "addr", peerTLSInfo)
	if err != nil {
		return nil, err
	}

	var cls *etcdserver.Cluster
	switch {
	case set["discovery"]:
		clusterStr := genClusterString(*name, apurls)
		cls, err = etcdserver.NewClusterFromString(*durl, clusterStr)
	case set["initial-cluster"]:
		fallthrough
	default:
		// We're statically configured, and cluster has appropriately been set.
		// Try to configure by indexing the static cluster by name.
		cls, err = etcdserver.NewClusterFromString(*initialClusterName, *initialCluster)
	}
	return cls, err
}

func mustNewMember(t *testing.T, name string) *member {
	var err error
	m := &member{}

	pln := newLocalListener(t)
	m.PeerListeners = []net.Listener{pln}
	m.PeerURLs, err = types.NewURLs([]string{"http://" + pln.Addr().String()})
	if err != nil {
		t.Fatal(err)
	}

	cln := newLocalListener(t)
	m.ClientListeners = []net.Listener{cln}
	m.ClientURLs, err = types.NewURLs([]string{"http://" + cln.Addr().String()})
	if err != nil {
		t.Fatal(err)
	}

	m.Name = name

	m.DataDir, err = ioutil.TempDir(os.TempDir(), "etcd")
	if err != nil {
		t.Fatal(err)
	}
	clusterStr := fmt.Sprintf("%s=http://%s", name, pln.Addr().String())
	m.Cluster, err = etcdserver.NewClusterFromString(clusterName, clusterStr)
	if err != nil {
		t.Fatal(err)
	}
	m.NewCluster = true
	m.Transport = mustNewTransport(t)
	m.ElectionTicks = electionTicks
	m.TickMs = uint(tickDuration / time.Millisecond)
	return m
}

// Clone returns a member with the same server configuration. The returned
// member will not set PeerListeners and ClientListeners.
func (m *member) Clone(t *testing.T) *member {
	mm := &member{}
	mm.ServerConfig = m.ServerConfig

	var err error
	clientURLStrs := m.ClientURLs.StringSlice()
	mm.ClientURLs, err = types.NewURLs(clientURLStrs)
	if err != nil {
		// this should never fail
		panic(err)
	}
	peerURLStrs := m.PeerURLs.StringSlice()
	mm.PeerURLs, err = types.NewURLs(peerURLStrs)
	if err != nil {
		// this should never fail
		panic(err)
	}
	clusterStr := m.Cluster.String()
	mm.Cluster, err = etcdserver.NewClusterFromString(clusterName, clusterStr)
	if err != nil {
		// this should never fail
		panic(err)
	}
	mm.Transport = mustNewTransport(t)
	mm.ElectionTicks = m.ElectionTicks
	return mm
}

func (c *cluster) AddMember(t *testing.T) {
	clusterStr := c.Members[0].Cluster.String()
	idx := len(c.Members)
	m := mustNewMember(t, c.name(idx))

	// send add request to the cluster
	cc := mustNewHTTPClient(t, []string{c.URL(0)})
	ma := client.NewMembersAPI(cc)
	ctx, cancel := context.WithTimeout(context.Background(), requestTimeout)
	peerURL := "http://" + m.PeerListeners[0].Addr().String()
	if _, err := ma.Add(ctx, peerURL); err != nil {
		t.Fatalf("add member on %s error: %v", c.URL(0), err)
	}
	cancel()

	// wait for the add node entry applied in the cluster
	members := append(c.HTTPMembers(), httptypes.Member{PeerURLs: []string{peerURL}, ClientURLs: []string{}})
	c.waitMembersMatch(t, members)

	for _, ln := range m.PeerListeners {
		clusterStr += fmt.Sprintf(",%s=http://%s", m.Name, ln.Addr().String())
	}
	var err error
	m.Cluster, err = etcdserver.NewClusterFromString(clusterName, clusterStr)
	if err != nil {
		t.Fatal(err)
	}
	m.NewCluster = false
	if err := m.Launch(); err != nil {
		t.Fatal(err)
	}
	c.Members = append(c.Members, m)
	// wait cluster to be stable to receive future client requests
	c.waitMembersMatch(t, c.HTTPMembers())
}

// startProxy launches an HTTP proxy for client communication which proxies to other etcd nodes.
func startProxy(cfg *config) error {
	cls, err := setupCluster(cfg)
	if err != nil {
		return fmt.Errorf("error setting up initial cluster: %v", err)
	}

	if cfg.durl != "" {
		s, err := discovery.GetCluster(cfg.durl, cfg.dproxy)
		if err != nil {
			return err
		}
		if cls, err = etcdserver.NewClusterFromString(cfg.durl, s); err != nil {
			return err
		}
	}

	pt, err := transport.NewTransport(cfg.clientTLSInfo)
	if err != nil {
		return err
	}

	// TODO(jonboulle): update peerURLs dynamically (i.e. when updating
	// clientURLs) instead of just using the initial fixed list here
	peerURLs := cls.PeerURLs()
	uf := func() []string {
		cls, err := etcdserver.GetClusterFromPeers(peerURLs)
		if err != nil {
			log.Printf("proxy: %v", err)
			return []string{}
		}
		return cls.ClientURLs()
	}
	ph := proxy.NewHandler(pt, uf)
	ph = &cors.CORSHandler{
		Handler: ph,
		Info:    cfg.corsInfo,
	}

	if cfg.isReadonlyProxy() {
		ph = proxy.NewReadonlyHandler(ph)
	}
	// Start a proxy server goroutine for each listen address
	for _, u := range cfg.lcurls {
		l, err := transport.NewListener(u.Host, u.Scheme, cfg.clientTLSInfo)
		if err != nil {
			return err
		}

		host := u.Host
		go func() {
			log.Print("proxy: listening for client requests on ", host)
			log.Fatal(http.Serve(l, ph))
		}()
	}
	return nil
}

// setupCluster sets up an initial cluster definition for bootstrap or discovery.
func setupCluster(cfg *config) (*etcdserver.Cluster, error) {
	var cls *etcdserver.Cluster
	var err error
	switch {
	default:
		// We're statically configured, and cluster has appropriately been set.
		cls, err = etcdserver.NewClusterFromString(cfg.initialClusterToken, cfg.initialCluster)
	}
	return cls, err
}

// setupCluster sets up an initial cluster definition for bootstrap or discovery.
func setupCluster(cfg *config) (*etcdserver.Cluster, error) {
	var cls *etcdserver.Cluster
	var err error
	switch {
	case cfg.durl != "":
		// If using discovery, generate a temporary cluster based on
		// self's advertised peer URLs
		clusterStr := genClusterString(cfg.name, cfg.apurls)
		cls, err = etcdserver.NewClusterFromString(cfg.durl, clusterStr)
	case cfg.dnsCluster != "":
		clusterStr, clusterToken, err := discovery.SRVGetCluster(cfg.name, cfg.dnsCluster, cfg.initialClusterToken, cfg.apurls)
		if err != nil {
			return nil, err
		}
		cls, err = etcdserver.NewClusterFromString(clusterToken, clusterStr)
	default:
		// We're statically configured, and cluster has appropriately been set.
		cls, err = etcdserver.NewClusterFromString(cfg.initialClusterToken, cfg.initialCluster)
	}
	return cls, err
}

// setupCluster sets up an initial cluster definition for bootstrap or discovery.
func setupCluster(apurls []url.URL) (*etcdserver.Cluster, error) {
	set := make(map[string]bool)
	fs.Visit(func(f *flag.Flag) {
		set[f.Name] = true
	})
	if set["discovery"] && set["initial-cluster"] {
		return nil, fmt.Errorf("both discovery and bootstrap-config are set")
	}
	var cls *etcdserver.Cluster
	var err error
	switch {
	case set["discovery"]:
		// If using discovery, generate a temporary cluster based on
		// self's advertised peer URLs
		clusterStr := genClusterString(*name, apurls)
		cls, err = etcdserver.NewClusterFromString(*durl, clusterStr)
	case set["initial-cluster"]:
		fallthrough
	default:
		// We're statically configured, and cluster has appropriately been set.
		cls, err = etcdserver.NewClusterFromString(*initialClusterToken, *initialCluster)
	}
	return cls, err
}

// TODO: support TLS
func (c *cluster) Launch(t *testing.T) {
	if c.Size <= 0 {
		t.Fatalf("cluster size <= 0")
	}

	lns := make([]net.Listener, c.Size)
	addrs := make([]string, c.Size)
	for i := 0; i < c.Size; i++ {
		l := newLocalListener(t)
		// each member claims only one peer listener
		lns[i] = l
		addrs[i] = fmt.Sprintf("%v=%v", c.name(i), "http://"+l.Addr().String())
	}
	clusterStr := strings.Join(addrs, ",")

	var err error
	for i := 0; i < c.Size; i++ {
		m := member{}
		m.PeerListeners = []net.Listener{lns[i]}
		cln := newLocalListener(t)
		m.ClientListeners = []net.Listener{cln}
		m.Name = c.name(i)
		m.ClientURLs, err = types.NewURLs([]string{"http://" + cln.Addr().String()})
		if err != nil {
			t.Fatal(err)
		}
		m.DataDir, err = ioutil.TempDir(os.TempDir(), "etcd")
		if err != nil {
			t.Fatal(err)
		}
		m.Cluster, err = etcdserver.NewClusterFromString(clusterName, clusterStr)
		if err != nil {
			t.Fatal(err)
		}
		m.ClusterState = etcdserver.ClusterStateValueNew
		m.Transport, err = transport.NewTransport(transport.TLSInfo{})
		if err != nil {
			t.Fatal(err)
		}
		// TODO: need the support of graceful stop in Sender to remove this
		m.Transport.DisableKeepAlives = true
		m.Transport.Dial = (&net.Dialer{Timeout: 100 * time.Millisecond}).Dial

		m.Launch(t)
		c.Members = append(c.Members, m)
	}
}

func fillClusterForMembers(ms []*member, cName string) error {
	addrs := make([]string, 0)
	for _, m := range ms {
		for _, l := range m.PeerListeners {
			addrs = append(addrs, fmt.Sprintf("%s=%s", m.Name, "http://"+l.Addr().String()))
		}
	}
	clusterStr := strings.Join(addrs, ",")
	var err error
	for _, m := range ms {
		m.Cluster, err = etcdserver.NewClusterFromString(cName, clusterStr)
		if err != nil {
			return err
		}
	}
	return nil
}

// startProxy launches an HTTP proxy for client communication which proxies to other etcd nodes.
func startProxy() error {
	apurls, err := flags.URLsFromFlags(fs, "initial-advertise-peer-urls", "addr", peerTLSInfo)
	if err != nil {
		return err
	}
	cls, err := setupCluster(apurls)
	if err != nil {
		return fmt.Errorf("error setting up initial cluster: %v", err)
	}

	if *durl != "" {
		s, err := discovery.GetCluster(*durl, *dproxy)
		if err != nil {
			return err
		}
		if cls, err = etcdserver.NewClusterFromString(*durl, s); err != nil {
			return err
		}
	}

	pt, err := transport.NewTransport(clientTLSInfo)
	if err != nil {
		return err
	}

	// TODO(jonboulle): update peerURLs dynamically (i.e. when updating
	// clientURLs) instead of just using the initial fixed list here
	peerURLs := cls.PeerURLs()
	uf := func() []string {
		cls, err := etcdserver.GetClusterFromPeers(peerURLs)
		if err != nil {
			log.Printf("proxy: %v", err)
			return []string{}
		}
		return cls.ClientURLs()
	}
	ph := proxy.NewHandler(pt, uf)
	ph = &cors.CORSHandler{
		Handler: ph,
		Info:    corsInfo,
	}

	if proxyFlag.String() == proxyFlagReadonly {
		ph = proxy.NewReadonlyHandler(ph)
	}
	lcurls, err := flags.URLsFromFlags(fs, "listen-client-urls", "bind-addr", clientTLSInfo)
	if err != nil {
		return err
	}
	// Start a proxy server goroutine for each listen address
	for _, u := range lcurls {
		l, err := transport.NewListener(u.Host, u.Scheme, clientTLSInfo)
		if err != nil {
			return err
		}

		host := u.Host
		go func() {
			log.Print("proxy: listening for client requests on ", host)
			log.Fatal(http.Serve(l, ph))
		}()
	}
	return nil
}

// startProxy launches an HTTP proxy for client communication which proxies to other etcd nodes.
func startProxy(cfg *config) error {
	cls, err := setupCluster(cfg)
	if err != nil {
		return fmt.Errorf("error setting up initial cluster: %v", err)
	}

	if cfg.durl != "" {
		s, err := discovery.GetCluster(cfg.durl, cfg.dproxy)
		if err != nil {
			return err
		}
		if cls, err = etcdserver.NewClusterFromString(cfg.durl, s); err != nil {
			return err
		}
	}

	pt, err := transport.NewTransport(cfg.clientTLSInfo)
	if err != nil {
		return err
	}

	tr, err := transport.NewTransport(cfg.peerTLSInfo)
	if err != nil {
		return err
	}

	if cfg.dir == "" {
		cfg.dir = fmt.Sprintf("%v.etcd", cfg.name)
		log.Printf("no proxy data-dir provided, using default proxy data-dir ./%s", cfg.dir)
	}
	cfg.dir = path.Join(cfg.dir, "proxy")
	err = os.MkdirAll(cfg.dir, 0700)
	if err != nil {
		return err
	}

	var peerURLs []string
	clusterfile := path.Join(cfg.dir, "cluster")

	b, err := ioutil.ReadFile(clusterfile)
	switch {
	case err == nil:
		urls := struct{ PeerURLs []string }{}
		err := json.Unmarshal(b, &urls)
		if err != nil {
			return err
		}
		peerURLs = urls.PeerURLs
		log.Printf("proxy: using peer urls %v from cluster file ./%s", peerURLs, clusterfile)
	case os.IsNotExist(err):
		peerURLs = cls.PeerURLs()
		log.Printf("proxy: using peer urls %v ", peerURLs)
	default:
		return err
	}

	uf := func() []string {
		gcls, err := etcdserver.GetClusterFromPeers(peerURLs, tr)
		// TODO: remove the 2nd check when we fix GetClusterFromPeers
		// GetClusterFromPeers should not return nil error with an invaild empty cluster
		if err != nil {
			log.Printf("proxy: %v", err)
			return []string{}
		}
		if len(gcls.Members()) == 0 {
			return cls.ClientURLs()
		}
		cls = gcls

		urls := struct{ PeerURLs []string }{cls.PeerURLs()}
		b, err := json.Marshal(urls)
		if err != nil {
			log.Printf("proxy: error on marshal peer urls %s", err)
			return cls.ClientURLs()
		}

		err = ioutil.WriteFile(clusterfile+".bak", b, 0600)
		if err != nil {
			log.Printf("proxy: error on writing urls %s", err)
			return cls.ClientURLs()
		}
		err = os.Rename(clusterfile+".bak", clusterfile)
		if err != nil {
			log.Printf("proxy: error on updating clusterfile %s", err)
			return cls.ClientURLs()
		}
		if !reflect.DeepEqual(cls.PeerURLs(), peerURLs) {
			log.Printf("proxy: updated peer urls in cluster file from %v to %v", peerURLs, cls.PeerURLs())
		}
		peerURLs = cls.PeerURLs()

		return cls.ClientURLs()
	}
	ph := proxy.NewHandler(pt, uf)
	ph = &cors.CORSHandler{
		Handler: ph,
		Info:    cfg.corsInfo,
	}

//.........这里部分代码省略.........