resize.go

/*
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 --replicas=3 replicationcontrollers foo
  resized

  # will only execute if the current size is 2
  $ kubectl resize --current-replicas=2 --replicas=3 replicationcontrollers foo
`,
		Run: func(cmd *cobra.Command, args []string) {
			count := GetFlagInt(cmd, "replicas")
			if len(args) != 2 || count < 0 {
				usageError(cmd, "--replicas=<count> <resource> <id>")
			}

			cmdNamespace, err := f.DefaultNamespace(cmd)
			checkErr(err)

			mapper, _ := f.Object(cmd)
			mapping, namespace, name := ResourceFromArgs(cmd, args, mapper, cmdNamespace)

			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
}