Kubelet: refactor pod manager

This change cleans up the pod manager extensively so that
 * Mirror pods are actually stored in the pod manager.
 * Both (non-mirror) pods and mirror pods are indexed by UID and full name for
   easy lookup and mapping. This is required for the next change to send
   full pod along with the pod status update.

This change also renames mirrorManager as mirrorClient since it is merely a
client to contact the API server and create/delete mirror pods.

pkg/kubelet/mirror_client.go

@@ -0,0 +1,95 @@
+/*
+Copyright 2015 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 kubelet
+
+import (
+	"fmt"
+
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/client"
+	"github.com/golang/glog"
+)
+
+// Mirror client is used to create/delete a mirror pod.
+
+type mirrorClient interface {
+	CreateMirrorPod(api.Pod, string) error
+	DeleteMirrorPod(string) error
+}
+
+type basicMirrorClient struct {
+	// mirror pods are stored in the kubelet directly because they need to be
+	// in sync with the internal pods.
+	apiserverClient client.Interface
+}
+
+func newBasicMirrorClient(apiserverClient client.Interface) *basicMirrorClient {
+	return &basicMirrorClient{apiserverClient: apiserverClient}
+}
+
+// Creates a mirror pod.
+func (self *basicMirrorClient) CreateMirrorPod(pod api.Pod, hostname string) error {
+	if self.apiserverClient == nil {
+		return nil
+	}
+	// Indicate that the pod should be scheduled to the current node.
+	pod.Spec.Host = hostname
+	pod.Annotations[ConfigMirrorAnnotationKey] = MirrorType
+
+	_, err := self.apiserverClient.Pods(NamespaceDefault).Create(&pod)
+	return err
+}
+
+// Deletes a mirror pod.
+func (self *basicMirrorClient) DeleteMirrorPod(podFullName string) error {
+	if self.apiserverClient == nil {
+		return nil
+	}
+	name, namespace, err := ParsePodFullName(podFullName)
+	if err != nil {
+		glog.Errorf("Failed to parse a pod full name %q", podFullName)
+		return err
+	}
+	glog.V(4).Infof("Deleting a mirror pod %q", podFullName)
+	if err := self.apiserverClient.Pods(namespace).Delete(name); err != nil {
+		glog.Errorf("Failed deleting a mirror pod %q: %v", podFullName, err)
+	}
+	return nil
+}
+
+// Helper functions.
+func getPodSource(pod *api.Pod) (string, error) {
+	if pod.Annotations != nil {
+		if source, ok := pod.Annotations[ConfigSourceAnnotationKey]; ok {
+			return source, nil
+		}
+	}
+	return "", fmt.Errorf("cannot get source of pod %q", pod.UID)
+}
+
+func isStaticPod(pod *api.Pod) bool {
+	source, err := getPodSource(pod)
+	return err == nil && source != ApiserverSource
+}
+
+func isMirrorPod(pod *api.Pod) bool {
+	if value, ok := pod.Annotations[ConfigMirrorAnnotationKey]; !ok {
+		return false
+	} else {
+		return value == MirrorType
+	}
+}