package tarexport import ( "encoding/json" "fmt" "io" "io/ioutil" "os" "path/filepath" "time" "github.com/docker/distribution" "github.com/docker/distribution/digest" "github.com/docker/docker/image" "github.com/docker/docker/image/v1" "github.com/docker/docker/layer" "github.com/docker/docker/pkg/archive" "github.com/docker/docker/pkg/system" "github.com/docker/docker/reference" ) type imageDescriptor struct { refs []reference.NamedTagged layers []string } type saveSession struct { *tarexporter outDir string images map[image.ID]*imageDescriptor savedLayers map[string]struct{} diffIDPaths map[layer.DiffID]string // cache every diffID blob to avoid duplicates } func (l *tarexporter) Save(names []string, outStream io.Writer) error { images, err := l.parseNames(names) if err != nil { return err } return (&saveSession{tarexporter: l, images: images}).save(outStream) } func (l *tarexporter) parseNames(names []string) (map[image.ID]*imageDescriptor, error) { imgDescr := make(map[image.ID]*imageDescriptor) addAssoc := func(id image.ID, ref reference.Named) { if _, ok := imgDescr[id]; !ok { imgDescr[id] = &imageDescriptor{} } if ref != nil { var tagged reference.NamedTagged if _, ok := ref.(reference.Canonical); ok { return } var ok bool if tagged, ok = ref.(reference.NamedTagged); !ok { var err error if tagged, err = reference.WithTag(ref, reference.DefaultTag); err != nil { return } } for _, t := range imgDescr[id].refs { if tagged.String() == t.String() { return } } imgDescr[id].refs = append(imgDescr[id].refs, tagged) } } for _, name := range names { id, ref, err := reference.ParseIDOrReference(name) if err != nil { return nil, err } if id != "" { _, err := l.is.Get(image.ID(id)) if err != nil { return nil, err } addAssoc(image.ID(id), nil) continue } if ref.Name() == string(digest.Canonical) { imgID, err := l.is.Search(name) if err != nil { return nil, err } addAssoc(imgID, nil) continue } if reference.IsNameOnly(ref) { assocs := l.rs.ReferencesByName(ref) for _, assoc := range assocs { addAssoc(assoc.ImageID, assoc.Ref) } if len(assocs) == 0 { imgID, err := l.is.Search(name) if err != nil { return nil, err } addAssoc(imgID, nil) } continue } var imgID image.ID if imgID, err = l.rs.Get(ref); err != nil { return nil, err } addAssoc(imgID, ref) } return imgDescr, nil } func (s *saveSession) save(outStream io.Writer) error { s.savedLayers = make(map[string]struct{}) s.diffIDPaths = make(map[layer.DiffID]string) // get image json tempDir, err := ioutil.TempDir("", "docker-export-") if err != nil { return err } defer os.RemoveAll(tempDir) s.outDir = tempDir reposLegacy := make(map[string]map[string]string) var manifest []manifestItem var parentLinks []parentLink for id, imageDescr := range s.images { foreignSrcs, err := s.saveImage(id) if err != nil { return err } var repoTags []string var layers []string for _, ref := range imageDescr.refs { if _, ok := reposLegacy[ref.Name()]; !ok { reposLegacy[ref.Name()] = make(map[string]string) } reposLegacy[ref.Name()][ref.Tag()] = imageDescr.layers[len(imageDescr.layers)-1] repoTags = append(repoTags, ref.String()) } for _, l := range imageDescr.layers { layers = append(layers, filepath.Join(l, legacyLayerFileName)) } manifest = append(manifest, manifestItem{ Config: digest.Digest(id).Hex() + ".json", RepoTags: repoTags, Layers: layers, LayerSources: foreignSrcs, }) parentID, _ := s.is.GetParent(id) parentLinks = append(parentLinks, parentLink{id, parentID}) s.tarexporter.loggerImgEvent.LogImageEvent(id.String(), id.String(), "save") } for i, p := range validatedParentLinks(parentLinks) { if p.parentID != "" { manifest[i].Parent = p.parentID } } if len(reposLegacy) > 0 { reposFile := filepath.Join(tempDir, legacyRepositoriesFileName) f, err := os.OpenFile(reposFile, os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0644) if err != nil { f.Close() return err } if err := json.NewEncoder(f).Encode(reposLegacy); err != nil { return err } if err := f.Close(); err != nil { return err } if err := system.Chtimes(reposFile, time.Unix(0, 0), time.Unix(0, 0)); err != nil { return err } } manifestFileName := filepath.Join(tempDir, manifestFileName) f, err := os.OpenFile(manifestFileName, os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0644) if err != nil { f.Close() return err } if err := json.NewEncoder(f).Encode(manifest); err != nil { return err } if err := f.Close(); err != nil { return err } if err := system.Chtimes(manifestFileName, time.Unix(0, 0), time.Unix(0, 0)); err != nil { return err } fs, err := archive.Tar(tempDir, archive.Uncompressed) if err != nil { return err } defer fs.Close() if _, err := io.Copy(outStream, fs); err != nil { return err } return nil } func (s *saveSession) saveImage(id image.ID) (map[layer.DiffID]distribution.Descriptor, error) { img, err := s.is.Get(id) if err != nil { return nil, err } if len(img.RootFS.DiffIDs) == 0 { return nil, fmt.Errorf("empty export - not implemented") } var parent digest.Digest var layers []string var foreignSrcs map[layer.DiffID]distribution.Descriptor for i := range img.RootFS.DiffIDs { v1Img := image.V1Image{} if i == len(img.RootFS.DiffIDs)-1 { v1Img = img.V1Image } rootFS := *img.RootFS rootFS.DiffIDs = rootFS.DiffIDs[:i+1] v1ID, err := v1.CreateID(v1Img, rootFS.ChainID(), parent) if err != nil { return nil, err } v1Img.ID = v1ID.Hex() if parent != "" { v1Img.Parent = parent.Hex() } src, err := s.saveLayer(rootFS.ChainID(), v1Img, img.Created) if err != nil { return nil, err } layers = append(layers, v1Img.ID) parent = v1ID if src.Digest != "" { if foreignSrcs == nil { foreignSrcs = make(map[layer.DiffID]distribution.Descriptor) } foreignSrcs[img.RootFS.DiffIDs[i]] = src } } configFile := filepath.Join(s.outDir, digest.Digest(id).Hex()+".json") if err := ioutil.WriteFile(configFile, img.RawJSON(), 0644); err != nil { return nil, err } if err := system.Chtimes(configFile, img.Created, img.Created); err != nil { return nil, err } s.images[id].layers = layers return foreignSrcs, nil } func (s *saveSession) saveLayer(id layer.ChainID, legacyImg image.V1Image, createdTime time.Time) (distribution.Descriptor, error) { if _, exists := s.savedLayers[legacyImg.ID]; exists { return distribution.Descriptor{}, nil } outDir := filepath.Join(s.outDir, legacyImg.ID) if err := os.Mkdir(outDir, 0755); err != nil { return distribution.Descriptor{}, err } // todo: why is this version file here? if err := ioutil.WriteFile(filepath.Join(outDir, legacyVersionFileName), []byte("1.0"), 0644); err != nil { return distribution.Descriptor{}, err } imageConfig, err := json.Marshal(legacyImg) if err != nil { return distribution.Descriptor{}, err } if err := ioutil.WriteFile(filepath.Join(outDir, legacyConfigFileName), imageConfig, 0644); err != nil { return distribution.Descriptor{}, err } // serialize filesystem layerPath := filepath.Join(outDir, legacyLayerFileName) l, err := s.ls.Get(id) if err != nil { return distribution.Descriptor{}, err } defer layer.ReleaseAndLog(s.ls, l) if oldPath, exists := s.diffIDPaths[l.DiffID()]; exists { relPath, err := filepath.Rel(layerPath, oldPath) if err != nil { return distribution.Descriptor{}, err } os.Symlink(relPath, layerPath) } else { tarFile, err := os.Create(layerPath) if err != nil { return distribution.Descriptor{}, err } defer tarFile.Close() arch, err := l.TarStream() if err != nil { return distribution.Descriptor{}, err } defer arch.Close() if _, err := io.Copy(tarFile, arch); err != nil { return distribution.Descriptor{}, err } for _, fname := range []string{"", legacyVersionFileName, legacyConfigFileName, legacyLayerFileName} { // todo: maybe save layer created timestamp? if err := system.Chtimes(filepath.Join(outDir, fname), createdTime, createdTime); err != nil { return distribution.Descriptor{}, err } } s.diffIDPaths[l.DiffID()] = layerPath } s.savedLayers[legacyImg.ID] = struct{}{} var src distribution.Descriptor if fs, ok := l.(distribution.Describable); ok { src = fs.Descriptor() } return src, nil }