// 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)

	return requestLogger(mux)
}

func main() {
	endpointStr := flag.String("agent-endpoints", "localhost:9027", "HTTP RPC endpoints of agents. Do not specify the schema.")
	datadir := flag.String("data-dir", "agent.etcd", "etcd data directory location on agent machine.")
	stressKeySize := flag.Int("stress-key-size", 100, "the size of each key written into etcd.")
	stressKeySuffixRange := flag.Int("stress-key-count", 250000, "the count of key range written into etcd.")
	limit := flag.Int("limit", 3, "the limit of rounds to run failure set.")
	isV2Only := flag.Bool("v2-only", false, "'true' to run V2 only tester.")
	flag.Parse()

	endpoints := strings.Split(*endpointStr, ",")
	c, err := newCluster(endpoints, *datadir, *stressKeySize, *stressKeySuffixRange, *isV2Only)
	if err != nil {
		plog.Fatal(err)
	}
	defer c.Terminate()

	t := &tester{
		failures: []failure{
			newFailureKillAll(),
			newFailureKillMajority(),
			newFailureKillOne(),
			newFailureKillLeader(),
			newFailureKillOneForLongTime(),
			newFailureKillLeaderForLongTime(),
			newFailureIsolate(),
			newFailureIsolateAll(),
		},
		cluster: c,
		limit:   *limit,
	}

	sh := statusHandler{status: &t.status}
	http.Handle("/status", sh)
	http.Handle("/metrics", prometheus.Handler())
	go func() { plog.Fatal(http.ListenAndServe(":9028", nil)) }()

	t.runLoop()
}

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

	pt, err := transport.NewTimeoutTransport(cfg.peerTLSInfo, time.Duration(cfg.proxyDialTimeoutMs)*time.Millisecond, time.Duration(cfg.proxyReadTimeoutMs)*time.Millisecond, time.Duration(cfg.proxyWriteTimeoutMs)*time.Millisecond)
	if err != nil {
		return err
	}
	pt.MaxIdleConnsPerHost = proxy.DefaultMaxIdleConnsPerHost

	tr, err := transport.NewTimeoutTransport(cfg.peerTLSInfo, time.Duration(cfg.proxyDialTimeoutMs)*time.Millisecond, time.Duration(cfg.proxyReadTimeoutMs)*time.Millisecond, time.Duration(cfg.proxyWriteTimeoutMs)*time.Millisecond)
	if err != nil {
		return err
	}

	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:
		if cfg.durl != "" {
			plog.Warningf("discovery token ignored since the proxy has already been initialized. Valid cluster file found at %q", clusterfile)
		}
		urls := struct{ PeerURLs []string }{}
		err := json.Unmarshal(b, &urls)
		if err != nil {
			return err
		}
		peerURLs = urls.PeerURLs
		plog.Infof("proxy: using peer urls %v from cluster file %q", peerURLs, clusterfile)
	case os.IsNotExist(err):
		if cfg.durl != "" {
			s, err := discovery.GetCluster(cfg.durl, cfg.dproxy)
			if err != nil {
				return err
			}
			if urlsmap, err = types.NewURLsMap(s); err != nil {
				return err
			}
		}
		peerURLs = urlsmap.URLs()
		plog.Infof("proxy: using peer urls %v ", peerURLs)
	default:
		return err
	}

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

		urls := struct{ PeerURLs []string }{gcls.PeerURLs()}
		b, err := json.Marshal(urls)
		if err != nil {
			plog.Warningf("proxy: error on marshal peer urls %s", err)
			return clientURLs
		}

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

		return clientURLs
	}
	ph := proxy.NewHandler(pt, uf, time.Duration(cfg.proxyFailureWaitMs)*time.Millisecond, time.Duration(cfg.proxyRefreshIntervalMs)*time.Millisecond)
	ph = &cors.CORSHandler{
		Handler: ph,
		Info:    cfg.corsInfo,
	}

//.........这里部分代码省略.........

// 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)
}

func ExampleRegister() {
	// Imagine you have a worker pool and want to count the tasks completed.
	taskCounter := prometheus.NewCounter(prometheus.CounterOpts{
		Subsystem: "worker_pool",
		Name:      "completed_tasks_total",
		Help:      "Total number of tasks completed.",
	})
	// This will register fine.
	if err := prometheus.Register(taskCounter); err != nil {
		fmt.Println(err)
	} else {
		fmt.Println("taskCounter registered.")
	}
	// Don't forget to tell the HTTP server about the Prometheus handler.
	// (In a real program, you still need to start the HTTP server...)
	http.Handle("/metrics", prometheus.Handler())

	// Now you can start workers and give every one of them a pointer to
	// taskCounter and let it increment it whenever it completes a task.
	taskCounter.Inc() // This has to happen somewhere in the worker code.

	// But wait, you want to see how individual workers perform. So you need
	// a vector of counters, with one element for each worker.
	taskCounterVec := prometheus.NewCounterVec(
		prometheus.CounterOpts{
			Subsystem: "worker_pool",
			Name:      "completed_tasks_total",
			Help:      "Total number of tasks completed.",
		},
		[]string{"worker_id"},
	)

	// Registering will fail because we already have a metric of that name.
	if err := prometheus.Register(taskCounterVec); err != nil {
		fmt.Println("taskCounterVec not registered:", err)
	} else {
		fmt.Println("taskCounterVec registered.")
	}

	// To fix, first unregister the old taskCounter.
	if prometheus.Unregister(taskCounter) {
		fmt.Println("taskCounter unregistered.")
	}

	// Try registering taskCounterVec again.
	if err := prometheus.Register(taskCounterVec); err != nil {
		fmt.Println("taskCounterVec not registered:", err)
	} else {
		fmt.Println("taskCounterVec registered.")
	}
	// Bummer! Still doesn't work.

	// Prometheus will not allow you to ever export metrics with
	// inconsistent help strings or label names. After unregistering, the
	// unregistered metrics will cease to show up in the /metrics HTTP
	// response, but the registry still remembers that those metrics had
	// been exported before. For this example, we will now choose a
	// different name. (In a real program, you would obviously not export
	// the obsolete metric in the first place.)
	taskCounterVec = prometheus.NewCounterVec(
		prometheus.CounterOpts{
			Subsystem: "worker_pool",
			Name:      "completed_tasks_by_id",
			Help:      "Total number of tasks completed.",
		},
		[]string{"worker_id"},
	)
	if err := prometheus.Register(taskCounterVec); err != nil {
		fmt.Println("taskCounterVec not registered:", err)
	} else {
		fmt.Println("taskCounterVec registered.")
	}
	// Finally it worked!

	// The workers have to tell taskCounterVec their id to increment the
	// right element in the metric vector.
	taskCounterVec.WithLabelValues("42").Inc() // Code from worker 42.

	// Each worker could also keep a reference to their own counter element
	// around. Pick the counter at initialization time of the worker.
	myCounter := taskCounterVec.WithLabelValues("42") // From worker 42 initialization code.
	myCounter.Inc()                                   // Somewhere in the code of that worker.

	// Note that something like WithLabelValues("42", "spurious arg") would
	// panic (because you have provided too many label values). If you want
	// to get an error instead, use GetMetricWithLabelValues(...) instead.
	notMyCounter, err := taskCounterVec.GetMetricWithLabelValues("42", "spurious arg")
	if err != nil {
		fmt.Println("Worker initialization failed:", err)
	}
	if notMyCounter == nil {
		fmt.Println("notMyCounter is nil.")
	}

	// A different (and somewhat tricky) approach is to use
	// ConstLabels. ConstLabels are pairs of label names and label values
	// that never change. You might ask what those labels are good for (and
	// rightfully so - if they never change, they could as well be part of
	// the metric name). There are essentially two use-cases: The first is
	// if labels are constant throughout the lifetime of a binary execution,
//.........这里部分代码省略.........