Split watch

pkg/apiserver/watch.go

@@ -0,0 +1,113 @@
+/*
+Copyright 2014 Google Inc. All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package apiserver
+
+import (
+	"encoding/json"
+	"net/http"
+
+	"code.google.com/p/go.net/websocket"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/httplog"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/watch"
+)
+
+// WatchServer serves a watch.Interface over a websocket or vanilla HTTP.
+type WatchServer struct {
+	watching watch.Interface
+}
+
+// HandleWS implements a websocket handler.
+func (w *WatchServer) HandleWS(ws *websocket.Conn) {
+	done := make(chan struct{})
+	go func() {
+		var unused interface{}
+		// Expect this to block until the connection is closed. Client should not
+		// send anything.
+		websocket.JSON.Receive(ws, &unused)
+		close(done)
+	}()
+	for {
+		select {
+		case <-done:
+			w.watching.Stop()
+			return
+		case event, ok := <-w.watching.ResultChan():
+			if !ok {
+				// End of results.
+				return
+			}
+			err := websocket.JSON.Send(ws, &api.WatchEvent{
+				Type:   event.Type,
+				Object: api.APIObject{event.Object},
+			})
+			if err != nil {
+				// Client disconnect.
+				w.watching.Stop()
+				return
+			}
+		}
+	}
+}
+
+// ServeHTTP serves a series of JSON encoded events via straight HTTP with
+// Transfer-Encoding: chunked.
+func (self *WatchServer) ServeHTTP(w http.ResponseWriter, req *http.Request) {
+	loggedW := httplog.LogOf(w)
+	w = httplog.Unlogged(w)
+
+	cn, ok := w.(http.CloseNotifier)
+	if !ok {
+		loggedW.Addf("unable to get CloseNotifier")
+		http.NotFound(loggedW, req)
+		return
+	}
+	flusher, ok := w.(http.Flusher)
+	if !ok {
+		loggedW.Addf("unable to get Flusher")
+		http.NotFound(loggedW, req)
+		return
+	}
+
+	loggedW.Header().Set("Transfer-Encoding", "chunked")
+	loggedW.WriteHeader(http.StatusOK)
+	flusher.Flush()
+
+	encoder := json.NewEncoder(w)
+	for {
+		select {
+		case <-cn.CloseNotify():
+			self.watching.Stop()
+			return
+		case event, ok := <-self.watching.ResultChan():
+			if !ok {
+				// End of results.
+				return
+			}
+			err := encoder.Encode(&api.WatchEvent{
+				Type:   event.Type,
+				Object: api.APIObject{event.Object},
+			})
+			if err != nil {
+				// Client disconnect.
+				self.watching.Stop()
+				return
+			}
+			flusher.Flush()
+		}
+	}
+}