Make kublet/util/format.go a separate package

The formatting function is used often in logging. This improves the readability
by shortening the length of the call. Also change the fomartted string to
include the pod UID.

pkg/kubelet/util/format/pod.go

@@ -0,0 +1,56 @@
+/*
+Copyright 2015 The Kubernetes Authors 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 format
+
+import (
+	"fmt"
+	"strings"
+
+	"k8s.io/kubernetes/pkg/api"
+)
+
+type podHandler func(*api.Pod) string
+
+// Pod returns a string representating a pod in a human readable
+// format. This function currently is the same as GetPodFullName in
+// kubelet/containers, but may differ in the future. As opposed to
+// GetPodFullName, this function is mainly used for logging.
+func Pod(pod *api.Pod) string {
+	// Use underscore as the delimiter because it is not allowed in pod name
+	// (DNS subdomain format), while allowed in the container name format.
+	return fmt.Sprintf("%s_%s", pod.Name, pod.Namespace)
+}
+
+// PodWithUID returns a string reprenetating a pod in a human readable format,
+// with pod UID as part of the string.
+func PodWithUID(pod *api.Pod) string {
+	return fmt.Sprintf("%s(%s)", Pod(pod), pod.UID)
+}
+
+// Pods returns a string representating a list of pods in a human
+// readable format.
+func Pods(pods []*api.Pod) string {
+	return aggregatePods(pods, PodWithUID)
+}
+
+func aggregatePods(pods []*api.Pod, handler podHandler) string {
+	podStrings := make([]string, 0, len(pods))
+	for _, pod := range pods {
+		podStrings = append(podStrings, handler(pod))
+	}
+	return fmt.Sprintf(strings.Join(podStrings, ", "))
+}