| package docker |
| |
| import ( |
| "fmt" |
| "io/ioutil" |
| "os" |
| "path" |
| "path/filepath" |
| "time" |
| ) |
| |
| type Graph struct { |
| Root string |
| } |
| |
| func NewGraph(root string) (*Graph, error) { |
| abspath, err := filepath.Abs(root) |
| if err != nil { |
| return nil, err |
| } |
| // Create the root directory if it doesn't exists |
| if err := os.Mkdir(root, 0700); err != nil && !os.IsExist(err) { |
| return nil, err |
| } |
| return &Graph{ |
| Root: abspath, |
| }, nil |
| } |
| |
| func (graph *Graph) Exists(id string) bool { |
| if _, err := graph.Get(id); err != nil { |
| return false |
| } |
| return true |
| } |
| |
| func (graph *Graph) Get(id string) (*Image, error) { |
| // FIXME: return nil when the image doesn't exist, instead of an error |
| img, err := LoadImage(graph.imageRoot(id)) |
| if err != nil { |
| return nil, err |
| } |
| if img.Id != id { |
| return nil, fmt.Errorf("Image stored at '%s' has wrong id '%s'", id, img.Id) |
| } |
| img.graph = graph |
| return img, nil |
| } |
| |
| func (graph *Graph) Create(layerData Archive, container *Container, comment string) (*Image, error) { |
| img := &Image{ |
| Id: GenerateId(), |
| Comment: comment, |
| Created: time.Now(), |
| } |
| if container != nil { |
| img.Parent = container.Image |
| img.Container = container.Id |
| img.ContainerConfig = *container.Config |
| } |
| if err := graph.Register(layerData, img); err != nil { |
| return nil, err |
| } |
| return img, nil |
| } |
| |
| func (graph *Graph) Register(layerData Archive, img *Image) error { |
| if err := ValidateId(img.Id); err != nil { |
| return err |
| } |
| // (This is a convenience to save time. Race conditions are taken care of by os.Rename) |
| if graph.Exists(img.Id) { |
| return fmt.Errorf("Image %s already exists", img.Id) |
| } |
| tmp, err := graph.Mktemp(img.Id) |
| defer os.RemoveAll(tmp) |
| if err != nil { |
| return fmt.Errorf("Mktemp failed: %s", err) |
| } |
| if err := StoreImage(img, layerData, tmp); err != nil { |
| return err |
| } |
| // Commit |
| if err := os.Rename(tmp, graph.imageRoot(img.Id)); err != nil { |
| return err |
| } |
| img.graph = graph |
| return nil |
| } |
| |
| func (graph *Graph) Mktemp(id string) (string, error) { |
| tmp, err := NewGraph(path.Join(graph.Root, ":tmp:")) |
| if err != nil { |
| return "", fmt.Errorf("Couldn't create temp: %s", err) |
| } |
| if tmp.Exists(id) { |
| return "", fmt.Errorf("Image %d already exists", id) |
| } |
| return tmp.imageRoot(id), nil |
| } |
| |
| func (graph *Graph) Garbage() (*Graph, error) { |
| return NewGraph(path.Join(graph.Root, ":garbage:")) |
| } |
| |
| func (graph *Graph) Delete(id string) error { |
| garbage, err := graph.Garbage() |
| if err != nil { |
| return err |
| } |
| return os.Rename(graph.imageRoot(id), garbage.imageRoot(id)) |
| } |
| |
| func (graph *Graph) Undelete(id string) error { |
| garbage, err := graph.Garbage() |
| if err != nil { |
| return err |
| } |
| return os.Rename(garbage.imageRoot(id), graph.imageRoot(id)) |
| } |
| |
| func (graph *Graph) GarbageCollect() error { |
| garbage, err := graph.Garbage() |
| if err != nil { |
| return err |
| } |
| return os.RemoveAll(garbage.Root) |
| } |
| |
| func (graph *Graph) Map() (map[string]*Image, error) { |
| // FIXME: this should replace All() |
| all, err := graph.All() |
| if err != nil { |
| return nil, err |
| } |
| images := make(map[string]*Image, len(all)) |
| for _, image := range all { |
| images[image.Id] = image |
| } |
| return images, nil |
| } |
| |
| func (graph *Graph) All() ([]*Image, error) { |
| var images []*Image |
| err := graph.WalkAll(func(image *Image) { |
| images = append(images, image) |
| }) |
| return images, err |
| } |
| |
| func (graph *Graph) WalkAll(handler func(*Image)) error { |
| files, err := ioutil.ReadDir(graph.Root) |
| if err != nil { |
| return err |
| } |
| for _, st := range files { |
| if img, err := graph.Get(st.Name()); err != nil { |
| // Skip image |
| continue |
| } else if handler != nil { |
| handler(img) |
| } |
| } |
| return nil |
| } |
| |
| func (graph *Graph) ByParent() (map[string][]*Image, error) { |
| byParent := make(map[string][]*Image) |
| err := graph.WalkAll(func(image *Image) { |
| image, err := graph.Get(image.Parent) |
| if err != nil { |
| return |
| } |
| if children, exists := byParent[image.Parent]; exists { |
| byParent[image.Parent] = []*Image{image} |
| } else { |
| byParent[image.Parent] = append(children, image) |
| } |
| }) |
| return byParent, err |
| } |
| |
| func (graph *Graph) Heads() (map[string]*Image, error) { |
| heads := make(map[string]*Image) |
| byParent, err := graph.ByParent() |
| if err != nil { |
| return nil, err |
| } |
| err = graph.WalkAll(func(image *Image) { |
| // If it's not in the byParent lookup table, then |
| // it's not a parent -> so it's a head! |
| if _, exists := byParent[image.Id]; !exists { |
| heads[image.Id] = image |
| } |
| }) |
| return heads, err |
| } |
| |
| func (graph *Graph) imageRoot(id string) string { |
| return path.Join(graph.Root, id) |
| } |