add get available versions commmand

pkg/api/unversioned.go

@@ -16,6 +16,10 @@ limitations under the License.
 
 package api
 
+import (
+	"strings"
+)
+
 // This file contains API types that are unversioned.
 
 // APIVersions lists the api versions that are available, to allow
@@ -49,3 +53,12 @@ func FieldSelectorQueryParam(version string) string {
 	}
 	return "field-selector"
 }
+
+// String returns available api versions as a human-friendly version string.
+func (apiVersions APIVersions) String() string {
+	return strings.Join(apiVersions.Versions, ",")
+}
+
+func (apiVersions APIVersions) GoString() string {
+	return apiVersions.String()
+}

pkg/kubectl/cmd/apiversions.go

@@ -0,0 +1,48 @@
+/*
+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 cmd
+
+import (
+	"io"
+
+	"github.com/spf13/cobra"
+
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/kubectl"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/kubectl/cmd/util"
+)
+
+func (f *Factory) NewCmdApiVersions(out io.Writer) *cobra.Command {
+	cmd := &cobra.Command{
+		Use:   "apiversions",
+		Short: "Print available API versions.",
+		Run: func(cmd *cobra.Command, args []string) {
+			err := RunApiVersions(f, out, cmd)
+			util.CheckErr(err)
+		},
+	}
+	return cmd
+}
+
+func RunApiVersions(f *Factory, out io.Writer, cmd *cobra.Command) error {
+	client, err := f.Client(cmd)
+	if err != nil {
+		return err
+	}
+
+	kubectl.GetApiVersions(out, client)
+	return nil
+}

pkg/kubectl/cmd/cmd.go

@@ -196,6 +196,7 @@ Find more information at https://github.com/GoogleCloudPlatform/kubernetes.`,
 	f.BindFlags(cmds.PersistentFlags())
 
 	cmds.AddCommand(f.NewCmdVersion(out))
+	cmds.AddCommand(f.NewCmdApiVersions(out))
 	cmds.AddCommand(f.NewCmdClusterInfo(out))
 	cmds.AddCommand(f.NewCmdProxy(out))
 

pkg/kubectl/version.go

@@ -40,3 +40,13 @@ func GetVersion(w io.Writer, kubeClient client.Interface) {
 func GetClientVersion(w io.Writer) {
 	fmt.Fprintf(w, "Client Version: %#v\n", version.Get())
 }
+
+func GetApiVersions(w io.Writer, kubeClient client.Interface) {
+	apiVersions, err := kubeClient.ServerAPIVersions()
+	if err != nil {
+		fmt.Printf("Couldn't get available api versions from server: %v\n", err)
+		os.Exit(1)
+	}
+
+	fmt.Fprintf(w, "Available Server Api Versions: %#v\n", *apiVersions)
+}