Added new command clusterinfo to kubectl

This is first version of the command. It prints IPs of master and cluster
services. Should be improved once generalized labels are implemented #341.

It requires label kubernet.io/cluster-service=true set for cluster services.

Follow up cl after discussion in #4417.

pkg/kubectl/cmd/clusterinfo.go

@@ -0,0 +1,72 @@
+/*
+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 cmd
+
+import (
+	"fmt"
+	"io"
+	"strings"
+
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/kubectl/resource"
+
+	"github.com/spf13/cobra"
+)
+
+func (f *Factory) NewCmdClusterInfo(out io.Writer) *cobra.Command {
+	cmd := &cobra.Command{
+		Use:   "clusterinfo",
+		Short: "Display cluster info",
+		Long:  "Display addresses of the master and services with label kubernetes.io/cluster-service=true",
+		Run: func(cmd *cobra.Command, args []string) {
+			RunClusterInfo(f, out, cmd)
+		},
+	}
+	return cmd
+}
+
+func RunClusterInfo(factory *Factory, out io.Writer, cmd *cobra.Command) {
+	client, err := factory.ClientConfig(cmd)
+	checkErr(err)
+	fmt.Fprintf(out, "Kubernetes master is running at %v\n", client.Host)
+
+	mapper, typer := factory.Object(cmd)
+	cmdNamespace, err := factory.DefaultNamespace(cmd)
+	checkErr(err)
+
+	// TODO: use generalized labels once they are implemented (#341)
+	b := resource.NewBuilder(mapper, typer, factory.ClientMapperForCommand(cmd)).
+		NamespaceParam(cmdNamespace).DefaultNamespace().
+		SelectorParam("kubernetes.io/cluster-service=true").
+		ResourceTypeOrNameArgs(false, []string{"services"}...).
+		Latest()
+	b.Do().Visit(func(r *resource.Info) error {
+		services := r.Object.(*api.ServiceList).Items
+		for _, service := range services {
+			splittedLink := strings.Split(strings.Split(service.ObjectMeta.SelfLink, "?")[0], "/")
+			// insert "proxy" into the link
+			splittedLink = append(splittedLink, "")
+			copy(splittedLink[4:], splittedLink[3:])
+			splittedLink[3] = "proxy"
+			link := strings.Join(splittedLink, "/")
+			fmt.Fprintf(out, "%v is running at %v%v/\n", service.ObjectMeta.Labels["name"], client.Host, link)
+		}
+		return nil
+	})
+
+	// TODO: consider printing more information about cluster
+}

pkg/kubectl/cmd/cmd.go

@@ -197,6 +197,7 @@ Find more information at https://github.com/GoogleCloudPlatform/kubernetes.`,
 	f.BindFlags(cmds.PersistentFlags())
 
 	cmds.AddCommand(f.NewCmdVersion(out))
+	cmds.AddCommand(f.NewCmdClusterInfo(out))
 	cmds.AddCommand(f.NewCmdProxy(out))
 
 	cmds.AddCommand(f.NewCmdGet(out))