Add a resize command to kubectl.

pkg/kubectl/cmd/cmd.go

@@ -62,6 +62,8 @@ type Factory struct {
 	Describer func(cmd *cobra.Command, mapping *meta.RESTMapping) (kubectl.Describer, error)
 	// Returns a Printer for formatting objects of the given type or an error.
 	Printer func(cmd *cobra.Command, mapping *meta.RESTMapping, noHeaders bool) (kubectl.ResourcePrinter, error)
+	// Returns a Resizer for changing the size of the specified RESTMapping type or an error
+	Resizer func(cmd *cobra.Command, mapping *meta.RESTMapping) (kubectl.Resizer, error)
 	// Returns a schema that can validate objects stored on disk.
 	Validator func(*cobra.Command) (validation.Schema, error)
 }
@@ -112,6 +114,17 @@ func NewFactory() *Factory {
 		Printer: func(cmd *cobra.Command, mapping *meta.RESTMapping, noHeaders bool) (kubectl.ResourcePrinter, error) {
 			return kubectl.NewHumanReadablePrinter(noHeaders), nil
 		},
+		Resizer: func(cmd *cobra.Command, mapping *meta.RESTMapping) (kubectl.Resizer, error) {
+			client, err := clients.ClientForVersion(mapping.APIVersion)
+			if err != nil {
+				return nil, err
+			}
+			resizer, ok := kubectl.ResizerFor(mapping.Kind, client)
+			if !ok {
+				return nil, fmt.Errorf("no resizer has been implemented for %q", mapping.Kind)
+			}
+			return resizer, nil
+		},
 		Validator: func(cmd *cobra.Command) (validation.Schema, error) {
 			if GetFlagBool(cmd, "validate") {
 				client, err := clients.ClientForVersion("")
@@ -173,6 +186,7 @@ Find more information at https://github.com/GoogleCloudPlatform/kubernetes.`,
 	cmds.AddCommand(NewCmdNamespace(out))
 	cmds.AddCommand(f.NewCmdLog(out))
 	cmds.AddCommand(f.NewCmdRollingUpdate(out))
+	cmds.AddCommand(f.NewCmdResize(out))
 
 	cmds.AddCommand(f.NewCmdRunContainer(out))
 

pkg/kubectl/cmd/resize.go

@@ -0,0 +1,68 @@
+/*
+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 (
+	"fmt"
+	"io"
+
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/kubectl"
+	"github.com/spf13/cobra"
+)
+
+func (f *Factory) NewCmdResize(out io.Writer) *cobra.Command {
+	cmd := &cobra.Command{
+		Use:   "resize [---resource-version=<version>] [--current-replicas=<count>] --replicas=<count> <resource> <id>",
+		Short: "Set a new size for a resizable resource (currently only Replication Controllers)",
+		Long: `Set a new size for a resizable resource (currently only Replication Controllers)
+
+Resize also allows users to specify one or more preconditions for the resize action.
+The new size is specified by --replicas=<n>. You can also specify an optional precondition. 
+The two currently supported options are --current-replicas or --resource-version.
+If a precondition is specified, it is validated before the resize is attempted, and it is 
+guaranteed that the precondition holds true when the resize is sent to the server.
+
+Examples:
+  $ kubectl resize replicationcontrollers foo 3
+  resized
+
+  # will only execute if the current size is 3
+  $ kubectl resize --current-replicas=2 replicationcontrollers foo 3
+`,
+		Run: func(cmd *cobra.Command, args []string) {
+			count := GetFlagInt(cmd, "replicas")
+			if len(args) != 2 || count < 0 {
+				usageError(cmd, "--replicas=<count> <resource> <id>")
+			}
+			mapper, _ := f.Object(cmd)
+			mapping, namespace, name := ResourceFromArgs(cmd, args, mapper)
+
+			resizer, err := f.Resizer(cmd, mapping)
+			checkErr(err)
+
+			resourceVersion := GetFlagString(cmd, "resource-version")
+			currentSize := GetFlagInt(cmd, "current-replicas")
+			s, err := resizer.Resize(namespace, name, &kubectl.ResizePrecondition{currentSize, resourceVersion}, uint(count))
+			checkErr(err)
+			fmt.Fprintf(out, "%s\n", s)
+		},
+	}
+	cmd.Flags().String("resource-version", "", "Precondition for resource version. Requires that the current resource version match this value in order to resize")
+	cmd.Flags().Int("current-replicas", -1, "Precondition for current size. Requires that the current size of the replication controller match this value in order to resize")
+	cmd.Flags().Int("replicas", -1, "The new number desired number of replicas.  Required.")
+	return cmd
+}