refactor to move kubectl.cmd.Factory to kubect/cmd/util

pkg/kubectl/cmd/util/clientcache.go

@@ -0,0 +1,76 @@
+/*
+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 util
+
+import (
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/client"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/client/clientcmd"
+)
+
+// clientCache caches previously loaded clients for reuse, and ensures MatchServerVersion
+// is invoked only once
+type clientCache struct {
+	loader        clientcmd.ClientConfig
+	clients       map[string]*client.Client
+	defaultConfig *client.Config
+	matchVersion  bool
+}
+
+// ClientConfigForVersion returns the correct config for a server
+func (c *clientCache) ClientConfigForVersion(version string) (*client.Config, error) {
+	if c.defaultConfig == nil {
+		config, err := c.loader.ClientConfig()
+		if err != nil {
+			return nil, err
+		}
+		c.defaultConfig = config
+		if c.matchVersion {
+			if err := client.MatchesServerVersion(config); err != nil {
+				return nil, err
+			}
+		}
+	}
+	// TODO: have a better config copy method
+	config := *c.defaultConfig
+	if len(version) != 0 {
+		config.Version = version
+	}
+	client.SetKubernetesDefaults(&config)
+
+	return &config, nil
+}
+
+// ClientForVersion initializes or reuses a client for the specified version, or returns an
+// error if that is not possible
+func (c *clientCache) ClientForVersion(version string) (*client.Client, error) {
+	config, err := c.ClientConfigForVersion(version)
+	if err != nil {
+		return nil, err
+	}
+
+	if client, ok := c.clients[config.Version]; ok {
+		return client, nil
+	}
+
+	client, err := client.New(config)
+	if err != nil {
+		return nil, err
+	}
+
+	c.clients[config.Version] = client
+	return client, nil
+}