package docker import ( "crypto/rand" "encoding/hex" "encoding/json" "fmt" "github.com/dotcloud/docker/archive" "github.com/dotcloud/docker/graphdriver" "github.com/dotcloud/docker/utils" "io" "io/ioutil" "os" "path" "strconv" "strings" "time" ) type Image struct { ID string `json:"id"` Parent string `json:"parent,omitempty"` Comment string `json:"comment,omitempty"` Created time.Time `json:"created"` Container string `json:"container,omitempty"` ContainerConfig Config `json:"container_config,omitempty"` DockerVersion string `json:"docker_version,omitempty"` Author string `json:"author,omitempty"` Config *Config `json:"config,omitempty"` Architecture string `json:"architecture,omitempty"` graph *Graph Size int64 } func LoadImage(root string) (*Image, error) { // Load the json data jsonData, err := ioutil.ReadFile(jsonPath(root)) if err != nil { return nil, err } img := &Image{} if err := json.Unmarshal(jsonData, img); err != nil { return nil, err } if err := ValidateID(img.ID); err != nil { return nil, err } if buf, err := ioutil.ReadFile(path.Join(root, "layersize")); err != nil { if !os.IsNotExist(err) { return nil, err } } else { if size, err := strconv.Atoi(string(buf)); err != nil { return nil, err } else { img.Size = int64(size) } } return img, nil } func StoreImage(img *Image, jsonData []byte, layerData archive.Archive, root, rootfs string) error { // Store the layer layer := rootfs if err := os.MkdirAll(layer, 0755); err != nil { return err } // If layerData is not nil, unpack it into the new layer if layerData != nil { if differ, ok := img.graph.driver.(graphdriver.Differ); ok { if err := differ.ApplyDiff(img.ID, layerData); err != nil { return err } } else { start := time.Now() utils.Debugf("Start untar layer") if err := archive.ApplyLayer(layer, layerData); err != nil { return err } utils.Debugf("Untar time: %vs", time.Now().Sub(start).Seconds()) } } // If raw json is provided, then use it if jsonData != nil { return ioutil.WriteFile(jsonPath(root), jsonData, 0600) } else { // Otherwise, unmarshal the image jsonData, err := json.Marshal(img) if err != nil { return err } if err := ioutil.WriteFile(jsonPath(root), jsonData, 0600); err != nil { return err } } // Compute and save the size of the rootfs size, err := utils.TreeSize(rootfs) if err != nil { return fmt.Errorf("Error computing size of rootfs %s: %s", img.ID, err) } img.Size = size if err := img.SaveSize(root); err != nil { return err } return nil } // SaveSize stores the current `size` value of `img` in the directory `root`. func (img *Image) SaveSize(root string) error { if err := ioutil.WriteFile(path.Join(root, "layersize"), []byte(strconv.Itoa(int(img.Size))), 0600); err != nil { return fmt.Errorf("Error storing image size in %s/layersize: %s", root, err) } return nil } func jsonPath(root string) string { return path.Join(root, "json") } // TarLayer returns a tar archive of the image's filesystem layer. func (image *Image) TarLayer(compression archive.Compression) (archive.Archive, error) { if image.graph == nil { return nil, fmt.Errorf("Can't load storage driver for unregistered image %s", image.ID) } layerPath, err := image.graph.driver.Get(image.ID) if err != nil { return nil, err } return archive.Tar(layerPath, compression) } func ValidateID(id string) error { if id == "" { return fmt.Errorf("Image id can't be empty") } if strings.Contains(id, ":") { return fmt.Errorf("Invalid character in image id: ':'") } return nil } func GenerateID() string { id := make([]byte, 32) _, err := io.ReadFull(rand.Reader, id) if err != nil { panic(err) // This shouldn't happen } return hex.EncodeToString(id) } // Image includes convenience proxy functions to its graph // These functions will return an error if the image is not registered // (ie. if image.graph == nil) func (img *Image) History() ([]*Image, error) { var parents []*Image if err := img.WalkHistory( func(img *Image) error { parents = append(parents, img) return nil }, ); err != nil { return nil, err } return parents, nil } func (img *Image) WalkHistory(handler func(*Image) error) (err error) { currentImg := img for currentImg != nil { if handler != nil { if err := handler(currentImg); err != nil { return err } } currentImg, err = currentImg.GetParent() if err != nil { return fmt.Errorf("Error while getting parent image: %v", err) } } return nil } func (img *Image) GetParent() (*Image, error) { if img.Parent == "" { return nil, nil } if img.graph == nil { return nil, fmt.Errorf("Can't lookup parent of unregistered image") } return img.graph.Get(img.Parent) } func (img *Image) root() (string, error) { if img.graph == nil { return "", fmt.Errorf("Can't lookup root of unregistered image") } return img.graph.imageRoot(img.ID), nil } func (img *Image) getParentsSize(size int64) int64 { parentImage, err := img.GetParent() if err != nil || parentImage == nil { return size } size += parentImage.Size return parentImage.getParentsSize(size) } // Build an Image object from raw json data func NewImgJSON(src []byte) (*Image, error) { ret := &Image{} utils.Debugf("Json string: {%s}", src) // FIXME: Is there a cleaner way to "purify" the input json? if err := json.Unmarshal(src, ret); err != nil { return nil, err } return ret, nil }