コード例 #1
0
ファイル: pull_v2.go プロジェクト: eldarion-gondor/cli
func newContentAddressableImage(v1Compatibility []byte, blobSum digest.Digest, parent digest.Digest) (contentAddressableDescriptor, error) {
	img := contentAddressableDescriptor{
		v1Compatibility: v1Compatibility,
	}

	var err error
	img.config, err = image.MakeImageConfig(v1Compatibility, blobSum, parent)
	if err != nil {
		return img, err
	}
	img.strongID, err = image.StrongID(img.config)
	if err != nil {
		return img, err
	}

	unmarshalledConfig, err := image.NewImgJSON(v1Compatibility)
	if err != nil {
		return img, err
	}

	img.compatibilityID = unmarshalledConfig.ID
	img.id = img.strongID.Hex()

	return img, nil
}
コード例 #2
0
ファイル: graph.go プロジェクト: eldarion-gondor/cli
// storeImage stores file system layer data for the given image to the
// graph's storage driver. Image metadata is stored in a file
// at the specified root directory.
func (graph *Graph) storeImage(id, parent string, config []byte, layerData io.Reader, root string) (err error) {
	var size int64
	// Store the layer. If layerData is not nil, unpack it into the new layer
	if layerData != nil {
		if size, err = graph.disassembleAndApplyTarLayer(id, parent, layerData, root); err != nil {
			return err
		}
	}

	if err := graph.saveSize(root, size); err != nil {
		return err
	}

	if err := ioutil.WriteFile(jsonPath(root), config, 0600); err != nil {
		return err
	}

	// If image is pointing to a parent via CompatibilityID write the reference to disk
	img, err := image.NewImgJSON(config)
	if err != nil {
		return err
	}

	if img.ParentID.Validate() == nil && parent != img.ParentID.Hex() {
		if err := ioutil.WriteFile(filepath.Join(root, parentFileName), []byte(parent), 0600); err != nil {
			return err
		}
	}
	return nil
}
コード例 #3
0
ファイル: push_v1.go プロジェクト: eldarion-gondor/cli
// getV1ID returns the compatibilityID for the ID in the graph. compatibilityID
// is read from from the v1Compatibility config file in the disk.
func (p *v1Pusher) getV1ID(id string) (string, error) {
	jsonData, err := p.getV1Config(id)
	if err != nil {
		return "", err
	}
	img, err := image.NewImgJSON(jsonData)
	if err != nil {
		return "", err
	}
	return img.ID, nil
}
コード例 #4
0
ファイル: load.go プロジェクト: devick/flynn
func (s *TagStore) recursiveLoad(eng *engine.Engine, address, tmpImageDir string) error {
	if err := eng.Job("image_get", address).Run(); err != nil {
		log.Debugf("Loading %s", address)

		imageJson, err := ioutil.ReadFile(path.Join(tmpImageDir, "repo", address, "json"))
		if err != nil {
			log.Debugf("Error reading json", err)
			return err
		}

		layer, err := os.Open(path.Join(tmpImageDir, "repo", address, "layer.tar"))
		if err != nil {
			log.Debugf("Error reading embedded tar", err)
			return err
		}
		img, err := image.NewImgJSON(imageJson)
		if err != nil {
			log.Debugf("Error unmarshalling json", err)
			return err
		}
		if err := utils.ValidateID(img.ID); err != nil {
			log.Debugf("Error validating ID: %s", err)
			return err
		}

		// ensure no two downloads of the same layer happen at the same time
		if c, err := s.poolAdd("pull", "layer:"+img.ID); err != nil {
			if c != nil {
				log.Debugf("Image (id: %s) load is already running, waiting: %v", img.ID, err)
				<-c
				return nil
			}

			return err
		}

		defer s.poolRemove("pull", "layer:"+img.ID)

		if img.Parent != "" {
			if !s.graph.Exists(img.Parent) {
				if err := s.recursiveLoad(eng, img.Parent, tmpImageDir); err != nil {
					return err
				}
			}
		}
		if err := s.graph.Register(img, layer); err != nil {
			return err
		}
	}
	log.Debugf("Completed processing %s", address)

	return nil
}
コード例 #5
0
ファイル: load.go プロジェクト: eldarion-gondor/cli
func (s *TagStore) recursiveLoad(address, tmpImageDir string) error {
	if _, err := s.LookupImage(address); err != nil {
		logrus.Debugf("Loading %s", address)

		imageJSON, err := ioutil.ReadFile(filepath.Join(tmpImageDir, "repo", address, "json"))
		if err != nil {
			logrus.Debugf("Error reading json: %v", err)
			return err
		}

		layer, err := os.Open(filepath.Join(tmpImageDir, "repo", address, "layer.tar"))
		if err != nil {
			logrus.Debugf("Error reading embedded tar: %v", err)
			return err
		}
		img, err := image.NewImgJSON(imageJSON)
		if err != nil {
			logrus.Debugf("Error unmarshalling json: %v", err)
			return err
		}
		if err := image.ValidateID(img.ID); err != nil {
			logrus.Debugf("Error validating ID: %v", err)
			return err
		}

		// ensure no two downloads of the same layer happen at the same time
		poolKey := "layer:" + img.ID
		broadcaster, found := s.poolAdd("pull", poolKey)
		if found {
			logrus.Debugf("Image (id: %s) load is already running, waiting", img.ID)
			return broadcaster.Wait()
		}

		defer s.poolRemove("pull", poolKey)

		if img.Parent != "" {
			if !s.graph.Exists(img.Parent) {
				if err := s.recursiveLoad(img.Parent, tmpImageDir); err != nil {
					return err
				}
			}
		}
		if err := s.graph.Register(v1Descriptor{img}, layer); err != nil {
			return err
		}
	}
	logrus.Debugf("Completed processing %s", address)

	return nil
}
コード例 #6
0
ファイル: pull_v2.go プロジェクト: eldarion-gondor/cli
// fixManifestLayers removes repeated layers from the manifest and checks the
// correctness of the parent chain.
func fixManifestLayers(m *manifest.Manifest) error {
	images := make([]*image.Image, len(m.FSLayers))
	for i := range m.FSLayers {
		img, err := image.NewImgJSON([]byte(m.History[i].V1Compatibility))
		if err != nil {
			return err
		}
		images[i] = img
		if err := image.ValidateID(img.ID); err != nil {
			return err
		}
	}

	if images[len(images)-1].Parent != "" {
		return errors.New("Invalid parent ID in the base layer of the image.")
	}

	// check general duplicates to error instead of a deadlock
	idmap := make(map[string]struct{})

	var lastID string
	for _, img := range images {
		// skip IDs that appear after each other, we handle those later
		if _, exists := idmap[img.ID]; img.ID != lastID && exists {
			return fmt.Errorf("ID %+v appears multiple times in manifest", img.ID)
		}
		lastID = img.ID
		idmap[lastID] = struct{}{}
	}

	// backwards loop so that we keep the remaining indexes after removing items
	for i := len(images) - 2; i >= 0; i-- {
		if images[i].ID == images[i+1].ID { // repeated ID. remove and continue
			m.FSLayers = append(m.FSLayers[:i], m.FSLayers[i+1:]...)
			m.History = append(m.History[:i], m.History[i+1:]...)
		} else if images[i].Parent != images[i+1].ID {
			return fmt.Errorf("Invalid parent ID. Expected %v, got %v.", images[i+1].ID, images[i].Parent)
		}
	}

	return nil
}
コード例 #7
0
ファイル: service.go プロジェクト: devick/flynn
// CmdSet stores a new image in the graph.
// Images are stored in the graph using 4 elements:
//	- A user-defined ID
//	- A collection of metadata describing the image
//	- A directory tree stored as a tar archive (also called the "layer")
//	- A reference to a "parent" ID on top of which the layer should be applied
//
// NOTE: even though the parent ID is only useful in relation to the layer and how
// to apply it (ie you could represent the full directory tree as 'parent_layer + layer',
// it is treated as a top-level property of the image. This is an artifact of early
// design and should probably be cleaned up in the future to simplify the design.
//
// Syntax: image_set ID
// Input:
//	- Layer content must be streamed in tar format on stdin. An empty input is
//	valid and represents a nil layer.
//
//	- Image metadata must be passed in the command environment.
//		'json': a json-encoded object with all image metadata.
//			It will be stored as-is, without any encoding/decoding artifacts.
//			That is a requirement of the current registry client implementation,
//			because a re-encoded json might invalidate the image checksum at
//			the next upload, even with functionaly identical content.
func (s *TagStore) CmdSet(job *engine.Job) error {
	if len(job.Args) != 1 {
		return fmt.Errorf("usage: %s NAME", job.Name)
	}
	var (
		imgJSON = []byte(job.Getenv("json"))
		layer   = job.Stdin
	)
	if len(imgJSON) == 0 {
		return fmt.Errorf("mandatory key 'json' is not set")
	}
	// We have to pass an *image.Image object, even though it will be completely
	// ignored in favor of the redundant json data.
	// FIXME: the current prototype of Graph.Register is stupid and redundant.
	img, err := image.NewImgJSON(imgJSON)
	if err != nil {
		return err
	}
	if err := s.graph.Register(img, layer); err != nil {
		return err
	}
	return nil
}
コード例 #8
0
ファイル: pull_v1.go プロジェクト: eldarion-gondor/cli
func (p *v1Puller) pullImage(out io.Writer, imgID, endpoint string) (layersDownloaded bool, err error) {
	var history []string
	history, err = p.session.GetRemoteHistory(imgID, endpoint)
	if err != nil {
		return false, err
	}
	out.Write(p.sf.FormatProgress(stringid.TruncateID(imgID), "Pulling dependent layers", nil))
	// FIXME: Try to stream the images?
	// FIXME: Launch the getRemoteImage() in goroutines

	sessionID := p.session.ID()
	// As imgID has been retained in pullRepository, no need to retain again
	p.graph.Retain(sessionID, history[1:]...)
	defer p.graph.Release(sessionID, history[1:]...)

	layersDownloaded = false
	for i := len(history) - 1; i >= 0; i-- {
		id := history[i]

		// ensure no two downloads of the same layer happen at the same time
		poolKey := "layer:" + id
		broadcaster, found := p.poolAdd("pull", poolKey)
		broadcaster.Add(out)
		if found {
			logrus.Debugf("Image (id: %s) pull is already running, skipping", id)
			err = broadcaster.Wait()
			if err != nil {
				return layersDownloaded, err
			}
			continue
		}

		// This must use a closure so it captures the value of err when
		// the function returns, not when the 'defer' is evaluated.
		defer func() {
			p.poolRemoveWithError("pull", poolKey, err)
		}()

		if !p.graph.Exists(id) {
			broadcaster.Write(p.sf.FormatProgress(stringid.TruncateID(id), "Pulling metadata", nil))
			var (
				imgJSON []byte
				imgSize int64
				err     error
				img     *image.Image
			)
			retries := 5
			for j := 1; j <= retries; j++ {
				imgJSON, imgSize, err = p.session.GetRemoteImageJSON(id, endpoint)
				if err != nil && j == retries {
					broadcaster.Write(p.sf.FormatProgress(stringid.TruncateID(id), "Error pulling dependent layers", nil))
					return layersDownloaded, err
				} else if err != nil {
					time.Sleep(time.Duration(j) * 500 * time.Millisecond)
					continue
				}
				img, err = image.NewImgJSON(imgJSON)
				layersDownloaded = true
				if err != nil && j == retries {
					broadcaster.Write(p.sf.FormatProgress(stringid.TruncateID(id), "Error pulling dependent layers", nil))
					return layersDownloaded, fmt.Errorf("Failed to parse json: %s", err)
				} else if err != nil {
					time.Sleep(time.Duration(j) * 500 * time.Millisecond)
					continue
				} else {
					break
				}
			}

			for j := 1; j <= retries; j++ {
				// Get the layer
				status := "Pulling fs layer"
				if j > 1 {
					status = fmt.Sprintf("Pulling fs layer [retries: %d]", j)
				}
				broadcaster.Write(p.sf.FormatProgress(stringid.TruncateID(id), status, nil))
				layer, err := p.session.GetRemoteImageLayer(img.ID, endpoint, imgSize)
				if uerr, ok := err.(*url.Error); ok {
					err = uerr.Err
				}
				if terr, ok := err.(net.Error); ok && terr.Timeout() && j < retries {
					time.Sleep(time.Duration(j) * 500 * time.Millisecond)
					continue
				} else if err != nil {
					broadcaster.Write(p.sf.FormatProgress(stringid.TruncateID(id), "Error pulling dependent layers", nil))
					return layersDownloaded, err
				}
				layersDownloaded = true
				defer layer.Close()

				err = p.graph.Register(v1Descriptor{img},
					progressreader.New(progressreader.Config{
						In:        layer,
						Out:       broadcaster,
						Formatter: p.sf,
						Size:      imgSize,
						NewLines:  false,
						ID:        stringid.TruncateID(id),
						Action:    "Downloading",
					}))
				if terr, ok := err.(net.Error); ok && terr.Timeout() && j < retries {
					time.Sleep(time.Duration(j) * 500 * time.Millisecond)
					continue
				} else if err != nil {
					broadcaster.Write(p.sf.FormatProgress(stringid.TruncateID(id), "Error downloading dependent layers", nil))
					return layersDownloaded, err
				} else {
					break
				}
			}
		}
		broadcaster.Write(p.sf.FormatProgress(stringid.TruncateID(id), "Download complete", nil))
		broadcaster.Close()
	}
	return layersDownloaded, nil
}
コード例 #9
0
ファイル: pull.go プロジェクト: devick/flynn
func (s *TagStore) pullV2Tag(eng *engine.Engine, r *registry.Session, out io.Writer, endpoint *registry.Endpoint, repoInfo *registry.RepositoryInfo, tag string, sf *utils.StreamFormatter, parallel bool, auth *registry.RequestAuthorization) (bool, error) {
	log.Debugf("Pulling tag from V2 registry: %q", tag)

	manifestBytes, manifestDigest, err := r.GetV2ImageManifest(endpoint, repoInfo.RemoteName, tag, auth)
	if err != nil {
		return false, err
	}

	// loadManifest ensures that the manifest payload has the expected digest
	// if the tag is a digest reference.
	manifest, verified, err := s.loadManifest(eng, manifestBytes, manifestDigest, tag)
	if err != nil {
		return false, fmt.Errorf("error verifying manifest: %s", err)
	}

	if err := checkValidManifest(manifest); err != nil {
		return false, err
	}

	if verified {
		log.Printf("Image manifest for %s has been verified", utils.ImageReference(repoInfo.CanonicalName, tag))
	}
	out.Write(sf.FormatStatus(tag, "Pulling from %s", repoInfo.CanonicalName))

	downloads := make([]downloadInfo, len(manifest.FSLayers))

	for i := len(manifest.FSLayers) - 1; i >= 0; i-- {
		var (
			sumStr  = manifest.FSLayers[i].BlobSum
			imgJSON = []byte(manifest.History[i].V1Compatibility)
		)

		img, err := image.NewImgJSON(imgJSON)
		if err != nil {
			return false, fmt.Errorf("failed to parse json: %s", err)
		}
		downloads[i].img = img

		// Check if exists
		if s.graph.Exists(img.ID) {
			log.Debugf("Image already exists: %s", img.ID)
			continue
		}

		dgst, err := digest.ParseDigest(sumStr)
		if err != nil {
			return false, err
		}
		downloads[i].digest = dgst

		out.Write(sf.FormatProgress(stringid.TruncateID(img.ID), "Pulling fs layer", nil))

		downloadFunc := func(di *downloadInfo) error {
			log.Debugf("pulling blob %q to V1 img %s", sumStr, img.ID)

			if c, err := s.poolAdd("pull", "img:"+img.ID); err != nil {
				if c != nil {
					out.Write(sf.FormatProgress(stringid.TruncateID(img.ID), "Layer already being pulled by another client. Waiting.", nil))
					<-c
					out.Write(sf.FormatProgress(stringid.TruncateID(img.ID), "Download complete", nil))
				} else {
					log.Debugf("Image (id: %s) pull is already running, skipping: %v", img.ID, err)
				}
			} else {
				defer s.poolRemove("pull", "img:"+img.ID)
				tmpFile, err := ioutil.TempFile("", "GetV2ImageBlob")
				if err != nil {
					return err
				}

				r, l, err := r.GetV2ImageBlobReader(endpoint, repoInfo.RemoteName, di.digest.Algorithm(), di.digest.Hex(), auth)
				if err != nil {
					return err
				}
				defer r.Close()

				verifier, err := digest.NewDigestVerifier(di.digest)
				if err != nil {
					return err
				}

				if _, err := io.Copy(tmpFile, progressreader.New(progressreader.Config{
					In:        ioutil.NopCloser(io.TeeReader(r, verifier)),
					Out:       out,
					Formatter: sf,
					Size:      int(l),
					NewLines:  false,
					ID:        stringid.TruncateID(img.ID),
					Action:    "Downloading",
				})); err != nil {
					return fmt.Errorf("unable to copy v2 image blob data: %s", err)
				}

				out.Write(sf.FormatProgress(stringid.TruncateID(img.ID), "Verifying Checksum", nil))

				if !verifier.Verified() {
					log.Infof("Image verification failed: checksum mismatch for %q", di.digest.String())
					verified = false
				}

				out.Write(sf.FormatProgress(stringid.TruncateID(img.ID), "Download complete", nil))

				log.Debugf("Downloaded %s to tempfile %s", img.ID, tmpFile.Name())
				di.tmpFile = tmpFile
				di.length = l
				di.downloaded = true
			}
			di.imgJSON = imgJSON

			return nil
		}

		if parallel {
			downloads[i].err = make(chan error)
			go func(di *downloadInfo) {
				di.err <- downloadFunc(di)
			}(&downloads[i])
		} else {
			err := downloadFunc(&downloads[i])
			if err != nil {
				return false, err
			}
		}
	}

	var tagUpdated bool
	for i := len(downloads) - 1; i >= 0; i-- {
		d := &downloads[i]
		if d.err != nil {
			err := <-d.err
			if err != nil {
				return false, err
			}
		}
		if d.downloaded {
			// if tmpFile is empty assume download and extracted elsewhere
			defer os.Remove(d.tmpFile.Name())
			defer d.tmpFile.Close()
			d.tmpFile.Seek(0, 0)
			if d.tmpFile != nil {
				err = s.graph.Register(d.img,
					progressreader.New(progressreader.Config{
						In:        d.tmpFile,
						Out:       out,
						Formatter: sf,
						Size:      int(d.length),
						ID:        stringid.TruncateID(d.img.ID),
						Action:    "Extracting",
					}))
				if err != nil {
					return false, err
				}

				// FIXME: Pool release here for parallel tag pull (ensures any downloads block until fully extracted)
			}
			out.Write(sf.FormatProgress(stringid.TruncateID(d.img.ID), "Pull complete", nil))
			tagUpdated = true
		} else {
			out.Write(sf.FormatProgress(stringid.TruncateID(d.img.ID), "Already exists", nil))
		}

	}

	// Check for new tag if no layers downloaded
	if !tagUpdated {
		repo, err := s.Get(repoInfo.LocalName)
		if err != nil {
			return false, err
		}
		if repo != nil {
			if _, exists := repo[tag]; !exists {
				tagUpdated = true
			}
		}
	}

	if verified && tagUpdated {
		out.Write(sf.FormatStatus(utils.ImageReference(repoInfo.CanonicalName, tag), "The image you are pulling has been verified. Important: image verification is a tech preview feature and should not be relied on to provide security."))
	}

	if manifestDigest != "" {
		out.Write(sf.FormatStatus("", "Digest: %s", manifestDigest))
	}

	if utils.DigestReference(tag) {
		if err = s.SetDigest(repoInfo.LocalName, tag, downloads[0].img.ID); err != nil {
			return false, err
		}
	} else {
		// only set the repository/tag -> image ID mapping when pulling by tag (i.e. not by digest)
		if err = s.Set(repoInfo.LocalName, tag, downloads[0].img.ID, true); err != nil {
			return false, err
		}
	}

	return tagUpdated, nil
}
コード例 #10
0
ファイル: pull.go プロジェクト: devick/flynn
func (s *TagStore) pullImage(r *registry.Session, out io.Writer, imgID, endpoint string, token []string, sf *utils.StreamFormatter) (bool, error) {
	history, err := r.GetRemoteHistory(imgID, endpoint, token)
	if err != nil {
		return false, err
	}
	out.Write(sf.FormatProgress(stringid.TruncateID(imgID), "Pulling dependent layers", nil))
	// FIXME: Try to stream the images?
	// FIXME: Launch the getRemoteImage() in goroutines

	layers_downloaded := false
	for i := len(history) - 1; i >= 0; i-- {
		id := history[i]

		// ensure no two downloads of the same layer happen at the same time
		if c, err := s.poolAdd("pull", "layer:"+id); err != nil {
			log.Debugf("Image (id: %s) pull is already running, skipping: %v", id, err)
			<-c
		}
		defer s.poolRemove("pull", "layer:"+id)

		if !s.graph.Exists(id) {
			out.Write(sf.FormatProgress(stringid.TruncateID(id), "Pulling metadata", nil))
			var (
				imgJSON []byte
				imgSize int
				err     error
				img     *image.Image
			)
			retries := 5
			for j := 1; j <= retries; j++ {
				imgJSON, imgSize, err = r.GetRemoteImageJSON(id, endpoint, token)
				if err != nil && j == retries {
					out.Write(sf.FormatProgress(stringid.TruncateID(id), "Error pulling dependent layers", nil))
					return layers_downloaded, err
				} else if err != nil {
					time.Sleep(time.Duration(j) * 500 * time.Millisecond)
					continue
				}
				img, err = image.NewImgJSON(imgJSON)
				layers_downloaded = true
				if err != nil && j == retries {
					out.Write(sf.FormatProgress(stringid.TruncateID(id), "Error pulling dependent layers", nil))
					return layers_downloaded, fmt.Errorf("Failed to parse json: %s", err)
				} else if err != nil {
					time.Sleep(time.Duration(j) * 500 * time.Millisecond)
					continue
				} else {
					break
				}
			}

			for j := 1; j <= retries; j++ {
				// Get the layer
				status := "Pulling fs layer"
				if j > 1 {
					status = fmt.Sprintf("Pulling fs layer [retries: %d]", j)
				}
				out.Write(sf.FormatProgress(stringid.TruncateID(id), status, nil))
				layer, err := r.GetRemoteImageLayer(img.ID, endpoint, token, int64(imgSize))
				if uerr, ok := err.(*url.Error); ok {
					err = uerr.Err
				}
				if terr, ok := err.(net.Error); ok && terr.Timeout() && j < retries {
					time.Sleep(time.Duration(j) * 500 * time.Millisecond)
					continue
				} else if err != nil {
					out.Write(sf.FormatProgress(stringid.TruncateID(id), "Error pulling dependent layers", nil))
					return layers_downloaded, err
				}
				layers_downloaded = true
				defer layer.Close()

				err = s.graph.Register(img,
					progressreader.New(progressreader.Config{
						In:        layer,
						Out:       out,
						Formatter: sf,
						Size:      imgSize,
						NewLines:  false,
						ID:        stringid.TruncateID(id),
						Action:    "Downloading",
					}))
				if terr, ok := err.(net.Error); ok && terr.Timeout() && j < retries {
					time.Sleep(time.Duration(j) * 500 * time.Millisecond)
					continue
				} else if err != nil {
					out.Write(sf.FormatProgress(stringid.TruncateID(id), "Error downloading dependent layers", nil))
					return layers_downloaded, err
				} else {
					break
				}
			}
		}
		out.Write(sf.FormatProgress(stringid.TruncateID(id), "Download complete", nil))
	}
	return layers_downloaded, nil
}
コード例 #11
0
ファイル: pull.go プロジェクト: josephwinston/flynn
func (s *TagStore) pullV2Tag(eng *engine.Engine, r *registry.Session, out io.Writer, localName, remoteName, tag string, sf *utils.StreamFormatter, parallel bool) (bool, error) {
	log.Debugf("Pulling tag from V2 registry: %q", tag)
	manifestBytes, err := r.GetV2ImageManifest(remoteName, tag, nil)
	if err != nil {
		return false, err
	}

	manifest, verified, err := s.verifyManifest(eng, manifestBytes)
	if err != nil {
		return false, fmt.Errorf("error verifying manifest: %s", err)
	}

	if len(manifest.FSLayers) != len(manifest.History) {
		return false, fmt.Errorf("length of history not equal to number of layers")
	}

	if verified {
		out.Write(sf.FormatStatus(localName+":"+tag, "The image you are pulling has been verified"))
	} else {
		out.Write(sf.FormatStatus(tag, "Pulling from %s", localName))
	}

	if len(manifest.FSLayers) == 0 {
		return false, fmt.Errorf("no blobSums in manifest")
	}

	downloads := make([]downloadInfo, len(manifest.FSLayers))

	for i := len(manifest.FSLayers) - 1; i >= 0; i-- {
		var (
			sumStr  = manifest.FSLayers[i].BlobSum
			imgJSON = []byte(manifest.History[i].V1Compatibility)
		)

		img, err := image.NewImgJSON(imgJSON)
		if err != nil {
			return false, fmt.Errorf("failed to parse json: %s", err)
		}
		downloads[i].img = img

		// Check if exists
		if s.graph.Exists(img.ID) {
			log.Debugf("Image already exists: %s", img.ID)
			continue
		}

		chunks := strings.SplitN(sumStr, ":", 2)
		if len(chunks) < 2 {
			return false, fmt.Errorf("expected 2 parts in the sumStr, got %#v", chunks)
		}
		sumType, checksum := chunks[0], chunks[1]
		out.Write(sf.FormatProgress(utils.TruncateID(img.ID), "Pulling fs layer", nil))

		downloadFunc := func(di *downloadInfo) error {
			log.Debugf("pulling blob %q to V1 img %s", sumStr, img.ID)

			if c, err := s.poolAdd("pull", "img:"+img.ID); err != nil {
				if c != nil {
					out.Write(sf.FormatProgress(utils.TruncateID(img.ID), "Layer already being pulled by another client. Waiting.", nil))
					<-c
					out.Write(sf.FormatProgress(utils.TruncateID(img.ID), "Download complete", nil))
				} else {
					log.Debugf("Image (id: %s) pull is already running, skipping: %v", img.ID, err)
				}
			} else {
				defer s.poolRemove("pull", "img:"+img.ID)
				tmpFile, err := ioutil.TempFile("", "GetV2ImageBlob")
				if err != nil {
					return err
				}

				r, l, err := r.GetV2ImageBlobReader(remoteName, sumType, checksum, nil)
				if err != nil {
					return err
				}
				defer r.Close()
				io.Copy(tmpFile, utils.ProgressReader(r, int(l), out, sf, false, utils.TruncateID(img.ID), "Downloading"))

				out.Write(sf.FormatProgress(utils.TruncateID(img.ID), "Download complete", nil))

				log.Debugf("Downloaded %s to tempfile %s", img.ID, tmpFile.Name())
				di.tmpFile = tmpFile
				di.length = l
				di.downloaded = true
			}
			di.imgJSON = imgJSON

			return nil
		}

		if parallel {
			downloads[i].err = make(chan error)
			go func(di *downloadInfo) {
				di.err <- downloadFunc(di)
			}(&downloads[i])
		} else {
			err := downloadFunc(&downloads[i])
			if err != nil {
				return false, err
			}
		}
	}

	var layersDownloaded bool
	for i := len(downloads) - 1; i >= 0; i-- {
		d := &downloads[i]
		if d.err != nil {
			err := <-d.err
			if err != nil {
				return false, err
			}
		}
		if d.downloaded {
			// if tmpFile is empty assume download and extracted elsewhere
			defer os.Remove(d.tmpFile.Name())
			defer d.tmpFile.Close()
			d.tmpFile.Seek(0, 0)
			if d.tmpFile != nil {
				err = s.graph.Register(d.img,
					utils.ProgressReader(d.tmpFile, int(d.length), out, sf, false, utils.TruncateID(d.img.ID), "Extracting"))
				if err != nil {
					return false, err
				}

				// FIXME: Pool release here for parallel tag pull (ensures any downloads block until fully extracted)
			}
			out.Write(sf.FormatProgress(utils.TruncateID(d.img.ID), "Pull complete", nil))
			layersDownloaded = true
		} else {
			out.Write(sf.FormatProgress(utils.TruncateID(d.img.ID), "Already exists", nil))
		}

	}

	if err = s.Set(localName, tag, downloads[0].img.ID, true); err != nil {
		return false, err
	}

	return layersDownloaded, nil
}