Remove proxy from kubernetes file (#2668)

Signed-off-by: Yong Tang <yong.tang.github@outlook.com>

plugin/kubernetes/apiproxy.go

-package kubernetes
-
-import (
-	"fmt"
-	"io"
-	"net"
-	"net/http"
-
-	"github.com/coredns/coredns/plugin/pkg/healthcheck"
-)
-
-type proxyHandler struct {
-	healthcheck.HealthCheck
-}
-
-type apiProxy struct {
-	http.Server
-	listener net.Listener
-	handler  proxyHandler
-}
-
-func (p *proxyHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
-	upstream := p.Select()
-	network := "tcp"
-	address := upstream.Name
-
-	d, err := net.Dial(network, address)
-	if err != nil {
-		log.Errorf("Unable to establish connection to upstream %s://%s: %s", network, address, err)
-		http.Error(w, fmt.Sprintf("Unable to establish connection to upstream %s://%s: %s", network, address, err), 500)
-		return
-	}
-	hj, ok := w.(http.Hijacker)
-	if !ok {
-		log.Error("Unable to establish connection: no hijacker")
-		http.Error(w, "Unable to establish connection: no hijacker", 500)
-		return
-	}
-	nc, _, err := hj.Hijack()
-	if err != nil {
-		log.Errorf("Unable to hijack connection: %s", err)
-		http.Error(w, fmt.Sprintf("Unable to hijack connection: %s", err), 500)
-		return
-	}
-	defer nc.Close()
-	defer d.Close()
-
-	err = r.Write(d)
-	if err != nil {
-		log.Errorf("Unable to copy connection to upstream %s://%s: %s", network, address, err)
-		http.Error(w, fmt.Sprintf("Unable to copy connection to upstream %s://%s: %s", network, address, err), 500)
-		return
-	}
-
-	errChan := make(chan error, 2)
-	cp := func(dst io.Writer, src io.Reader) {
-		_, err := io.Copy(dst, src)
-		errChan <- err
-	}
-	go cp(d, nc)
-	go cp(nc, d)
-	<-errChan
-}
-
-func (p *apiProxy) Run() {
-	p.handler.Start()
-	go func() {
-		p.Serve(p.listener)
-	}()
-}
-
-func (p *apiProxy) Stop() {
-	p.handler.Stop()
-	p.listener.Close()
-}

plugin/kubernetes/kubernetes.go

@@ -31,7 +31,6 @@ type Kubernetes struct {
 	Zones            []string
 	Upstream         *upstream.Upstream
 	APIServerList    []string
-	APIProxy         *apiProxy
 	APICertAuth      string
 	APIClientCert    string
 	APIClientKey     string

plugin/kubernetes/setup.go

@@ -80,9 +80,6 @@ func setup(c *caddy.Controller) error {
 func (k *Kubernetes) RegisterKubeCache(c *caddy.Controller) {
 	c.OnStartup(func() error {
 		go k.APIConn.Run()
-		if k.APIProxy != nil {
-			k.APIProxy.Run()
-		}
 
 		timeout := time.After(5 * time.Second)
 		ticker := time.NewTicker(100 * time.Millisecond)
@@ -99,9 +96,6 @@ func (k *Kubernetes) RegisterKubeCache(c *caddy.Controller) {
 	})
 
 	c.OnShutdown(func() error {
-		if k.APIProxy != nil {
-			k.APIProxy.Stop()
-		}
 		return k.APIConn.Stop()
 	})
 }