| package graph |
| |
| import ( |
| "compress/gzip" |
| "crypto/sha256" |
| "fmt" |
| "io" |
| "io/ioutil" |
| "os" |
| "path/filepath" |
| "runtime" |
| "strings" |
| "syscall" |
| "time" |
| |
| "github.com/Sirupsen/logrus" |
| "github.com/docker/distribution/digest" |
| "github.com/docker/docker/autogen/dockerversion" |
| "github.com/docker/docker/daemon/graphdriver" |
| "github.com/docker/docker/image" |
| "github.com/docker/docker/pkg/archive" |
| "github.com/docker/docker/pkg/progressreader" |
| "github.com/docker/docker/pkg/streamformatter" |
| "github.com/docker/docker/pkg/stringid" |
| "github.com/docker/docker/pkg/system" |
| "github.com/docker/docker/pkg/truncindex" |
| "github.com/docker/docker/runconfig" |
| ) |
| |
| // A Graph is a store for versioned filesystem images and the relationship between them. |
| type Graph struct { |
| Root string |
| idIndex *truncindex.TruncIndex |
| driver graphdriver.Driver |
| } |
| |
| // NewGraph instantiates a new graph at the given root path in the filesystem. |
| // `root` will be created if it doesn't exist. |
| func NewGraph(root string, driver graphdriver.Driver) (*Graph, error) { |
| abspath, err := filepath.Abs(root) |
| if err != nil { |
| return nil, err |
| } |
| // Create the root directory if it doesn't exists |
| if err := system.MkdirAll(root, 0700); err != nil && !os.IsExist(err) { |
| return nil, err |
| } |
| |
| graph := &Graph{ |
| Root: abspath, |
| idIndex: truncindex.NewTruncIndex([]string{}), |
| driver: driver, |
| } |
| if err := graph.restore(); err != nil { |
| return nil, err |
| } |
| return graph, nil |
| } |
| |
| func (graph *Graph) restore() error { |
| dir, err := ioutil.ReadDir(graph.Root) |
| if err != nil { |
| return err |
| } |
| var ids = []string{} |
| for _, v := range dir { |
| id := v.Name() |
| if graph.driver.Exists(id) { |
| ids = append(ids, id) |
| } |
| } |
| graph.idIndex = truncindex.NewTruncIndex(ids) |
| logrus.Debugf("Restored %d elements", len(dir)) |
| return nil |
| } |
| |
| // FIXME: Implement error subclass instead of looking at the error text |
| // Note: This is the way golang implements os.IsNotExists on Plan9 |
| func (graph *Graph) IsNotExist(err error, id string) bool { |
| return err != nil && (strings.Contains(strings.ToLower(err.Error()), "does not exist") || strings.Contains(strings.ToLower(err.Error()), "no such")) && strings.Contains(err.Error(), id) |
| } |
| |
| // Exists returns true if an image is registered at the given id. |
| // If the image doesn't exist or if an error is encountered, false is returned. |
| func (graph *Graph) Exists(id string) bool { |
| if _, err := graph.Get(id); err != nil { |
| return false |
| } |
| return true |
| } |
| |
| // Get returns the image with the given id, or an error if the image doesn't exist. |
| func (graph *Graph) Get(name string) (*image.Image, error) { |
| id, err := graph.idIndex.Get(name) |
| if err != nil { |
| return nil, fmt.Errorf("could not find image: %v", err) |
| } |
| img, err := image.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.SetGraph(graph) |
| |
| if img.Size < 0 { |
| size, err := graph.driver.DiffSize(img.ID, img.Parent) |
| if err != nil { |
| return nil, fmt.Errorf("unable to calculate size of image id %q: %s", img.ID, err) |
| } |
| |
| img.Size = size |
| if err := img.SaveSize(graph.ImageRoot(id)); err != nil { |
| return nil, err |
| } |
| } |
| return img, nil |
| } |
| |
| // Create creates a new image and registers it in the graph. |
| func (graph *Graph) Create(layerData archive.ArchiveReader, containerID, containerImage, comment, author string, containerConfig, config *runconfig.Config) (*image.Image, error) { |
| img := &image.Image{ |
| ID: stringid.GenerateRandomID(), |
| Comment: comment, |
| Created: time.Now().UTC(), |
| DockerVersion: dockerversion.VERSION, |
| Author: author, |
| Config: config, |
| Architecture: runtime.GOARCH, |
| OS: runtime.GOOS, |
| } |
| |
| if containerID != "" { |
| img.Parent = containerImage |
| img.Container = containerID |
| img.ContainerConfig = *containerConfig |
| } |
| |
| if err := graph.Register(img, layerData); err != nil { |
| return nil, err |
| } |
| return img, nil |
| } |
| |
| // Register imports a pre-existing image into the graph. |
| func (graph *Graph) Register(img *image.Image, layerData archive.ArchiveReader) (err error) { |
| defer func() { |
| // If any error occurs, remove the new dir from the driver. |
| // Don't check for errors since the dir might not have been created. |
| // FIXME: this leaves a possible race condition. |
| if err != nil { |
| graph.driver.Remove(img.ID) |
| } |
| }() |
| if err := image.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) |
| } |
| |
| // Ensure that the image root does not exist on the filesystem |
| // when it is not registered in the graph. |
| // This is common when you switch from one graph driver to another |
| if err := os.RemoveAll(graph.ImageRoot(img.ID)); err != nil && !os.IsNotExist(err) { |
| return err |
| } |
| |
| // If the driver has this ID but the graph doesn't, remove it from the driver to start fresh. |
| // (the graph is the source of truth). |
| // Ignore errors, since we don't know if the driver correctly returns ErrNotExist. |
| // (FIXME: make that mandatory for drivers). |
| graph.driver.Remove(img.ID) |
| |
| tmp, err := graph.Mktemp("") |
| defer os.RemoveAll(tmp) |
| if err != nil { |
| return fmt.Errorf("Mktemp failed: %s", err) |
| } |
| |
| // Create root filesystem in the driver |
| if err := graph.driver.Create(img.ID, img.Parent); err != nil { |
| return fmt.Errorf("Driver %s failed to create image rootfs %s: %s", graph.driver, img.ID, err) |
| } |
| // Apply the diff/layer |
| img.SetGraph(graph) |
| if err := image.StoreImage(img, layerData, tmp); err != nil { |
| return err |
| } |
| // Commit |
| if err := os.Rename(tmp, graph.ImageRoot(img.ID)); err != nil { |
| return err |
| } |
| graph.idIndex.Add(img.ID) |
| return nil |
| } |
| |
| // TempLayerArchive creates a temporary archive of the given image's filesystem layer. |
| // The archive is stored on disk and will be automatically deleted as soon as has been read. |
| // If output is not nil, a human-readable progress bar will be written to it. |
| // FIXME: does this belong in Graph? How about MktempFile, let the caller use it for archives? |
| func (graph *Graph) TempLayerArchive(id string, sf *streamformatter.StreamFormatter, output io.Writer) (*archive.TempArchive, error) { |
| image, err := graph.Get(id) |
| if err != nil { |
| return nil, err |
| } |
| tmp, err := graph.Mktemp("") |
| if err != nil { |
| return nil, err |
| } |
| a, err := image.TarLayer() |
| if err != nil { |
| return nil, err |
| } |
| progressReader := progressreader.New(progressreader.Config{ |
| In: a, |
| Out: output, |
| Formatter: sf, |
| Size: 0, |
| NewLines: false, |
| ID: stringid.TruncateID(id), |
| Action: "Buffering to disk", |
| }) |
| defer progressReader.Close() |
| return archive.NewTempArchive(progressReader, tmp) |
| } |
| |
| // Mktemp creates a temporary sub-directory inside the graph's filesystem. |
| func (graph *Graph) Mktemp(id string) (string, error) { |
| dir := filepath.Join(graph.Root, "_tmp", stringid.GenerateRandomID()) |
| if err := system.MkdirAll(dir, 0700); err != nil { |
| return "", err |
| } |
| return dir, nil |
| } |
| |
| func (graph *Graph) newTempFile() (*os.File, error) { |
| tmp, err := graph.Mktemp("") |
| if err != nil { |
| return nil, err |
| } |
| return ioutil.TempFile(tmp, "") |
| } |
| |
| func bufferToFile(f *os.File, src io.Reader) (int64, digest.Digest, error) { |
| var ( |
| h = sha256.New() |
| w = gzip.NewWriter(io.MultiWriter(f, h)) |
| ) |
| _, err := io.Copy(w, src) |
| w.Close() |
| if err != nil { |
| return 0, "", err |
| } |
| n, err := f.Seek(0, os.SEEK_CUR) |
| if err != nil { |
| return 0, "", err |
| } |
| if _, err := f.Seek(0, 0); err != nil { |
| return 0, "", err |
| } |
| return n, digest.NewDigest("sha256", h), nil |
| } |
| |
| // setupInitLayer populates a directory with mountpoints suitable |
| // for bind-mounting dockerinit into the container. The mountpoint is simply an |
| // empty file at /.dockerinit |
| // |
| // This extra layer is used by all containers as the top-most ro layer. It protects |
| // the container from unwanted side-effects on the rw layer. |
| func SetupInitLayer(initLayer string) error { |
| for pth, typ := range map[string]string{ |
| "/dev/pts": "dir", |
| "/dev/shm": "dir", |
| "/proc": "dir", |
| "/sys": "dir", |
| "/.dockerinit": "file", |
| "/.dockerenv": "file", |
| "/etc/resolv.conf": "file", |
| "/etc/hosts": "file", |
| "/etc/hostname": "file", |
| "/dev/console": "file", |
| "/etc/mtab": "/proc/mounts", |
| } { |
| parts := strings.Split(pth, "/") |
| prev := "/" |
| for _, p := range parts[1:] { |
| prev = filepath.Join(prev, p) |
| syscall.Unlink(filepath.Join(initLayer, prev)) |
| } |
| |
| if _, err := os.Stat(filepath.Join(initLayer, pth)); err != nil { |
| if os.IsNotExist(err) { |
| if err := system.MkdirAll(filepath.Join(initLayer, filepath.Dir(pth)), 0755); err != nil { |
| return err |
| } |
| switch typ { |
| case "dir": |
| if err := system.MkdirAll(filepath.Join(initLayer, pth), 0755); err != nil { |
| return err |
| } |
| case "file": |
| f, err := os.OpenFile(filepath.Join(initLayer, pth), os.O_CREATE, 0755) |
| if err != nil { |
| return err |
| } |
| f.Close() |
| default: |
| if err := os.Symlink(typ, filepath.Join(initLayer, pth)); err != nil { |
| return err |
| } |
| } |
| } else { |
| return err |
| } |
| } |
| } |
| |
| // Layer is ready to use, if it wasn't before. |
| return nil |
| } |
| |
| // Check if given error is "not empty". |
| // Note: this is the way golang does it internally with os.IsNotExists. |
| func isNotEmpty(err error) bool { |
| switch pe := err.(type) { |
| case nil: |
| return false |
| case *os.PathError: |
| err = pe.Err |
| case *os.LinkError: |
| err = pe.Err |
| } |
| return strings.Contains(err.Error(), " not empty") |
| } |
| |
| // Delete atomically removes an image from the graph. |
| func (graph *Graph) Delete(name string) error { |
| id, err := graph.idIndex.Get(name) |
| if err != nil { |
| return err |
| } |
| tmp, err := graph.Mktemp("") |
| graph.idIndex.Delete(id) |
| if err == nil { |
| if err := os.Rename(graph.ImageRoot(id), tmp); err != nil { |
| // On err make tmp point to old dir and cleanup unused tmp dir |
| os.RemoveAll(tmp) |
| tmp = graph.ImageRoot(id) |
| } |
| } else { |
| // On err make tmp point to old dir for cleanup |
| tmp = graph.ImageRoot(id) |
| } |
| // Remove rootfs data from the driver |
| graph.driver.Remove(id) |
| // Remove the trashed image directory |
| return os.RemoveAll(tmp) |
| } |
| |
| // Map returns a list of all images in the graph, addressable by ID. |
| func (graph *Graph) Map() (map[string]*image.Image, error) { |
| images := make(map[string]*image.Image) |
| err := graph.walkAll(func(image *image.Image) { |
| images[image.ID] = image |
| }) |
| if err != nil { |
| return nil, err |
| } |
| return images, nil |
| } |
| |
| // walkAll iterates over each image in the graph, and passes it to a handler. |
| // The walking order is undetermined. |
| func (graph *Graph) walkAll(handler func(*image.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 |
| } |
| |
| // ByParent returns a lookup table of images by their parent. |
| // If an image of id ID has 3 children images, then the value for key ID |
| // will be a list of 3 images. |
| // If an image has no children, it will not have an entry in the table. |
| func (graph *Graph) ByParent() (map[string][]*image.Image, error) { |
| byParent := make(map[string][]*image.Image) |
| err := graph.walkAll(func(img *image.Image) { |
| parent, err := graph.Get(img.Parent) |
| if err != nil { |
| return |
| } |
| if children, exists := byParent[parent.ID]; exists { |
| byParent[parent.ID] = append(children, img) |
| } else { |
| byParent[parent.ID] = []*image.Image{img} |
| } |
| }) |
| return byParent, err |
| } |
| |
| // Heads returns all heads in the graph, keyed by id. |
| // A head is an image which is not the parent of another image in the graph. |
| func (graph *Graph) Heads() (map[string]*image.Image, error) { |
| heads := make(map[string]*image.Image) |
| byParent, err := graph.ByParent() |
| if err != nil { |
| return nil, err |
| } |
| err = graph.walkAll(func(image *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 filepath.Join(graph.Root, id) |
| } |
| |
| func (graph *Graph) Driver() graphdriver.Driver { |
| return graph.driver |
| } |