volume.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 volume

import (
	"io/ioutil"
	"os"
	"path"
)

// Volume represents a directory used by pods or hosts on a node.
// All method implementations of methods in the volume interface must be idempotent.
type Volume interface {
	// GetPath returns the directory path the volume is mounted to.
	GetPath() string
}

// Builder interface provides method to set up/mount the volume.
type Builder interface {
	// Uses Interface to provide the path for Docker binds.
	Volume
	// SetUp prepares and mounts/unpacks the volume to a self-determined
	// directory path.  This may be called more than once, so
	// implementations must be idempotent.
	SetUp() error
	// SetUpAt prepares and mounts/unpacks the volume to the specified
	// directory path, which may or may not exist yet.  This may be called
	// more than once, so implementations must be idempotent.
	SetUpAt(dir string) error
}

// Cleaner interface provides method to cleanup/unmount the volumes.
type Cleaner interface {
	Volume
	// TearDown unmounts the volume from a self-determined directory and
	// removes traces of the SetUp procedure.
	TearDown() error
	// TearDown unmounts the volume from the specified directory and
	// removes traces of the SetUp procedure.
	TearDownAt(dir string) error
}

func RenameDirectory(oldPath, newName string) (string, error) {
	newPath, err := ioutil.TempDir(path.Dir(oldPath), newName)
	if err != nil {
		return "", err
	}
	err = os.Rename(oldPath, newPath)
	if err != nil {
		return "", err
	}
	return newPath, nil
}