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moby--moby/image/image.go

342 lines
6.9 KiB
Go

package image
import (
"io"
"io/ioutil"
"encoding/json"
"time"
"path"
"path/filepath"
"errors"
"sort"
"os"
"github.com/dotcloud/docker/future"
"strings"
)
type Store struct {
*Index
Root string
Layers *LayerStore
}
func New(root string) (*Store, error) {
abspath, err := filepath.Abs(root)
if err != nil {
return nil, err
}
layers, err := NewLayerStore(path.Join(root, "layers"))
if err != nil {
return nil, err
}
if err := layers.Init(); err != nil {
return nil, err
}
return &Store{
Root: abspath,
Index: NewIndex(path.Join(root, "index.json")),
Layers: layers,
}, nil
}
type Compression uint32
const (
Uncompressed Compression = iota
Bzip2
Gzip
)
func (store *Store) Import(name string, archive io.Reader, stderr io.Writer, parent *Image, compression Compression) (*Image, error) {
layer, err := store.Layers.AddLayer(archive, stderr, compression)
if err != nil {
return nil, err
}
layers := []string{layer}
if parent != nil {
layers = append(layers, parent.Layers...)
}
var parentId string
if parent != nil {
parentId = parent.Id
}
return store.Create(name, parentId, layers...)
}
func (store *Store) Create(name string, source string, layers ...string) (*Image, error) {
image, err := NewImage(name, layers, source)
if err != nil {
return nil, err
}
if err := store.Index.Add(name, image); err != nil {
return nil, err
}
return image, nil
}
// Index
type Index struct {
Path string
ByName map[string]*History
ById map[string]*Image
}
func NewIndex(path string) *Index {
return &Index{
Path: path,
ByName: make(map[string]*History),
ById: make(map[string]*Image),
}
}
func (index *Index) Exists(id string) bool {
_, exists := index.ById[id]
return exists
}
func (index *Index) Find(idOrName string) *Image {
// Load
if err := index.load(); err != nil {
return nil
}
// Lookup by ID
if image, exists := index.ById[idOrName]; exists {
return image
}
// Lookup by name
if history, exists := index.ByName[idOrName]; exists && history.Len() > 0 {
return (*history)[0]
}
return nil
}
func (index *Index) Add(name string, image *Image) error {
// Load
if err := index.load(); err != nil {
return err
}
if _, exists := index.ByName[name]; !exists {
index.ByName[name] = new(History)
} else {
// If this image is already the latest version, don't add it.
if (*index.ByName[name])[0].Id == image.Id {
return nil
}
}
index.ByName[name].Add(image)
index.ById[image.Id] = image
// Save
if err := index.save(); err != nil {
return err
}
return nil
}
func (index *Index) Copy(srcNameOrId, dstName string) (*Image, error) {
if srcNameOrId == "" || dstName == "" {
return nil, errors.New("Illegal image name")
}
// Load
if err := index.load(); err != nil {
return nil, err
}
src := index.Find(srcNameOrId)
if src == nil {
return nil, errors.New("No such image: " + srcNameOrId)
}
dst, err := NewImage(dstName, src.Layers, src.Id)
if err != nil {
return nil, err
}
if err := index.Add(dstName, dst); err != nil {
return nil, err
}
// Save
if err := index.save(); err != nil {
return nil, err
}
return dst, nil
}
func (index *Index) Rename(oldName, newName string) error {
// Load
if err := index.load(); err != nil {
return err
}
if _, exists := index.ByName[oldName]; !exists {
return errors.New("Can't rename " + oldName + ": no such image.")
}
if _, exists := index.ByName[newName]; exists {
return errors.New("Can't rename to " + newName + ": name is already in use.")
}
index.ByName[newName] = index.ByName[oldName]
delete(index.ByName, oldName)
// Change the ID of all images, since they include the name
for _, image := range *index.ByName[newName] {
if id, err := generateImageId(newName, image.Layers); err != nil {
return err
} else {
oldId := image.Id
image.Id = id
index.ById[id] = image
delete(index.ById, oldId)
}
}
// Save
if err := index.save(); err != nil {
return err
}
return nil
}
// Delete deletes all images with the name `name`
func (index *Index) Delete(name string) error {
// Load
if err := index.load(); err != nil {
return err
}
if _, exists := index.ByName[name]; !exists {
return errors.New("No such image: " + name)
}
// Remove from index lookup
for _, image := range *index.ByName[name] {
delete(index.ById, image.Id)
}
// Remove from name lookup
delete(index.ByName, name)
// Save
if err := index.save(); err != nil {
return err
}
return nil
}
func (index *Index) Names() []string {
if err := index.load(); err != nil {
return []string{}
}
var names[]string
for name := range index.ByName {
names = append(names, name)
}
sort.Strings(names)
return names
}
func (index *Index) load() error {
jsonData, err := ioutil.ReadFile(index.Path)
if err != nil {
if os.IsNotExist(err) {
return nil
}
return err
}
path := index.Path
if err := json.Unmarshal(jsonData, index); err != nil {
return err
}
index.Path = path
return nil
}
func (index *Index) save() error {
jsonData, err := json.Marshal(index)
if err != nil {
return err
}
if err := ioutil.WriteFile(index.Path, jsonData, 0600); err != nil {
return err
}
return nil
}
// History wraps an array of images so they can be sorted by date (most recent first)
type History []*Image
func (history *History) Len() int {
return len(*history)
}
func (history *History) Less(i, j int) bool {
images := *history
return images[j].Created.Before(images[i].Created)
}
func (history *History) Swap(i, j int) {
images := *history
tmp := images[i]
images[i] = images[j]
images[j] = tmp
}
func (history *History) Add(image *Image) {
*history = append(*history, image)
sort.Sort(history)
}
func (history *History) Del(id string) {
for idx, image := range *history {
if image.Id == id {
*history = append((*history)[:idx], (*history)[idx + 1:]...)
}
}
}
type Image struct {
Id string // Globally unique identifier
Layers []string // Absolute paths
Created time.Time
Parent string
}
func (image *Image) IdParts() (string, string) {
if len(image.Id) < 8 {
return "", image.Id
}
hash := image.Id[len(image.Id)-8:len(image.Id)]
name := image.Id[:len(image.Id)-9]
return name, hash
}
func (image *Image) IdIsFinal() bool {
return len(image.Layers) == 1
}
func generateImageId(name string, layers []string) (string, error) {
if len(layers) == 0 {
return "", errors.New("No layers provided.")
}
var hash string
if len(layers) == 1 {
hash = path.Base(layers[0])
} else {
var ids string
for _, layer := range layers {
ids += path.Base(layer)
}
if h, err := future.ComputeId(strings.NewReader(ids)); err != nil {
return "", err
} else {
hash = h
}
}
return name + ":" + hash, nil
}
func NewImage(name string, layers []string, parent string) (*Image, error) {
id, err := generateImageId(name, layers)
if err != nil {
return nil, err
}
return &Image{
Id: id,
Layers: layers,
Created: time.Now(),
Parent: parent,
}, nil
}