move apigateway into apiserver (#1948)

pkg/apiserver/dispatch/dispatch.go

@@ -0,0 +1,36 @@
+package dispatch
+
+import (
+	"k8s.io/apiserver/pkg/endpoints/handlers/responsewriters"
+	"net/http"
+
+	"k8s.io/apimachinery/pkg/util/proxy"
+)
+
+// Dispatcher defines how to forward request to desired cluster apiserver
+type Dispatcher interface {
+	Dispatch(w http.ResponseWriter, req *http.Request)
+}
+
+var DefaultClusterDispatch = newClusterDispatch()
+
+type clusterDispatch struct {
+	transport *http.Transport
+}
+
+func newClusterDispatch() Dispatcher {
+	return &clusterDispatch{}
+}
+
+func (c *clusterDispatch) Dispatch(w http.ResponseWriter, req *http.Request) {
+
+	u := *req.URL
+	// u.Host = someHost
+
+	httpProxy := proxy.NewUpgradeAwareHandler(&u, c.transport, false, false, c)
+	httpProxy.ServeHTTP(w, req)
+}
+
+func (c *clusterDispatch) Error(w http.ResponseWriter, req *http.Request, err error) {
+	responsewriters.InternalError(w, req, err)
+}