Merge pull request #419 from brendandburns/health

Add a /healthz handler to the kubelet server

pkg/healthz/doc.go

@@ -0,0 +1,20 @@
+/*
+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 healthz implements basic http server health checking.
+// Usage:
+//   import _ "healthz" registers a handler on the path '/healthz', that serves 200s
+package healthz

pkg/healthz/healthz.go

@@ -0,0 +1,31 @@
+/*
+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 healthz
+
+import (
+	"net/http"
+)
+
+func init() {
+	http.HandleFunc("/healthz", handleHealthz)
+}
+
+func handleHealthz(w http.ResponseWriter, r *http.Request) {
+	// TODO Support user supplied health functions too.
+	w.WriteHeader(http.StatusOK)
+	w.Write([]byte("ok"))
+}

pkg/kubelet/kubelet.go

@@ -34,6 +34,7 @@ import (
 	"time"
 
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
+	_ "github.com/GoogleCloudPlatform/kubernetes/pkg/healthz"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/tools"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/util"
 	"github.com/coreos/go-etcd/etcd"
@@ -145,8 +146,9 @@ func (kl *Kubelet) RunKubelet(dockerEndpoint, configPath, manifestURL, etcdServe
 	if address != "" {
 		glog.Infof("Starting to listen on %s:%d", address, port)
 		handler := KubeletServer{
-			Kubelet:       kl,
+			Kubelet:         kl,
-			UpdateChannel: updateChannel,
+			UpdateChannel:   updateChannel,
+			DelegateHandler: http.DefaultServeMux,
 		}
 		s := &http.Server{
 			Addr:           net.JoinHostPort(address, strconv.FormatUint(uint64(port), 10)),

pkg/kubelet/kubelet_server.go

@@ -33,8 +33,9 @@ import (
 
 // KubeletServer is a http.Handler which exposes kubelet functionality over HTTP.
 type KubeletServer struct {
-	Kubelet       kubeletInterface
+	Kubelet         kubeletInterface
-	UpdateChannel chan<- manifestUpdate
+	UpdateChannel   chan<- manifestUpdate
+	DelegateHandler http.Handler
 }
 
 // kubeletInterface contains all the kubelet methods required by the server.
@@ -105,7 +106,7 @@ func (s *KubeletServer) ServeHTTP(w http.ResponseWriter, req *http.Request) {
 	case strings.HasPrefix(u.Path, "/stats"):
 		s.serveStats(w, req)
 	default:
-		http.Error(w, "Not found.", http.StatusNotFound)
+		s.DelegateHandler.ServeHTTP(w, req)
 	}
 }