client-go http trace分析耗时

klog.InitFlags(nil)
flag.Parse()
defer klog.Flush()

cfg, err := clientcmd.BuildConfigFromFlags("", "/root/.kube/config")
if err != nil {
	klog.Fatalf("Error building kubeconfig: %s", err.Error())
}

kubeClient, err := kubernetes.NewForConfig(cfg)
if err != nil {
	klog.Fatalf("Error building kubernetes clientset: %s", err.Error())
}

informerFactory := informers.NewSharedInformerFactory(kubeClient, 0)
hasSynced := informerFactory.Core().V1().Nodes().Informer().HasSynced
informerFactory.Core().V1().Nodes().Lister()
informerFactory.Core().V1().Nodes().Informer()

newStopCh := make(chan struct{})
informerFactory.Start(newStopCh)

klog.Infof("begin to wait cache sync")
if ok := cache.WaitForCacheSync(newStopCh, hasSynced); !ok {
	klog.Fatalf("failed to wait for caches to sync")
}
klog.Infof("wait cache sync end")

# 指定klog日志级别是9
./test --v=9

# client-go项目中round_trippers.go 耗时统计来源
if rt.levels[DebugDetailedTiming] {
	var getConn, dnsStart, dialStart, tlsStart, serverStart time.Time
	var host string
	trace := &httptrace.ClientTrace{
		// DNS
		DNSStart: func(info httptrace.DNSStartInfo) {
			reqInfo.muTrace.Lock()
			defer reqInfo.muTrace.Unlock()
			dnsStart = time.Now()
			host = info.Host
		},
		DNSDone: func(info httptrace.DNSDoneInfo) {
			reqInfo.muTrace.Lock()
			defer reqInfo.muTrace.Unlock()
			reqInfo.DNSLookup = time.Since(dnsStart)
			klog.Infof("HTTP Trace: DNS Lookup for %s resolved to %v", host, info.Addrs)
		},
		// Dial
		ConnectStart: func(network, addr string) {
			reqInfo.muTrace.Lock()
			defer reqInfo.muTrace.Unlock()
			dialStart = time.Now()
		},
		ConnectDone: func(network, addr string, err error) {
			reqInfo.muTrace.Lock()
			defer reqInfo.muTrace.Unlock()
			reqInfo.Dialing = time.Since(dialStart)
			if err != nil {
				klog.Infof("HTTP Trace: Dial to %s:%s failed: %v", network, addr, err)
			} else {
				klog.Infof("HTTP Trace: Dial to %s:%s succeed", network, addr)
			}
		},
		// TLS
		TLSHandshakeStart: func() {
			tlsStart = time.Now()
		},
		TLSHandshakeDone: func(_ tls.ConnectionState, _ error) {
			reqInfo.muTrace.Lock()
			defer reqInfo.muTrace.Unlock()
			reqInfo.TLSHandshake = time.Since(tlsStart)
		},
		// Connection (it can be DNS + Dial or just the time to get one from the connection pool)
		GetConn: func(hostPort string) {
			getConn = time.Now()
		},
		GotConn: func(info httptrace.GotConnInfo) {
			reqInfo.muTrace.Lock()
			defer reqInfo.muTrace.Unlock()
			reqInfo.GetConnection = time.Since(getConn)
			reqInfo.ConnectionReused = info.Reused
		},
		// Server Processing (time since we wrote the request until first byte is received)
		WroteRequest: func(info httptrace.WroteRequestInfo) {
			reqInfo.muTrace.Lock()
			defer reqInfo.muTrace.Unlock()
			serverStart = time.Now()
		},
		GotFirstResponseByte: func() {
			reqInfo.muTrace.Lock()
			defer reqInfo.muTrace.Unlock()
			reqInfo.ServerProcessing = time.Since(serverStart)
		},
	}
	req = req.WithContext(httptrace.WithClientTrace(req.Context(), trace))
}

DNS(域名解析)->Dial(建立连接)->TLS(证书认证)->Server Processing(请求和响应)