Golang Image.MarshalJSON方法代码示例

// Execute the scratch-n-push
func (s *DockerScratchPushStep) Execute(ctx context.Context, sess *core.Session) (int, error) {
	// This is clearly only relevant to docker so we're going to dig into the
	// transport internals a little bit to get the container ID
	dt := sess.Transport().(*DockerTransport)
	containerID := dt.containerID

	_, err := s.CollectArtifact(containerID)
	if err != nil {
		return -1, err
	}

	// layer.tar has an extra folder in it so we have to strip it :/
	artifactReader, err := os.Open(s.options.HostPath("layer.tar"))
	if err != nil {
		return -1, err
	}
	defer artifactReader.Close()

	layerFile, err := os.OpenFile(s.options.HostPath("real_layer.tar"), os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0644)
	if err != nil {
		return -1, err
	}
	defer layerFile.Close()

	dgst := digest.Canonical.New()
	mwriter := io.MultiWriter(layerFile, dgst.Hash())

	tr := tar.NewReader(artifactReader)
	tw := tar.NewWriter(mwriter)

	for {
		hdr, err := tr.Next()
		if err == io.EOF {
			// finished the tarball
			break
		}

		if err != nil {
			return -1, err
		}

		// Skip the base dir
		if hdr.Name == "./" {
			continue
		}

		if strings.HasPrefix(hdr.Name, "output/") {
			hdr.Name = hdr.Name[len("output/"):]
		} else if strings.HasPrefix(hdr.Name, "source/") {
			hdr.Name = hdr.Name[len("source/"):]
		}

		if len(hdr.Name) == 0 {
			continue
		}

		tw.WriteHeader(hdr)
		_, err = io.Copy(tw, tr)
		if err != nil {
			return -1, err
		}
	}

	digest := dgst.Digest()

	config := &container.Config{
		Cmd:          s.cmd,
		Entrypoint:   s.entrypoint,
		Hostname:     containerID[:16],
		WorkingDir:   s.workingDir,
		Volumes:      s.volumes,
		ExposedPorts: tranformPorts(s.ports),
	}

	// Make the JSON file we need
	t := time.Now()
	base := image.V1Image{
		Architecture: "amd64",
		Container:    containerID,
		ContainerConfig: container.Config{
			Hostname: containerID[:16],
		},
		DockerVersion: "1.10",
		Created:       t,
		OS:            "linux",
		Config:        config,
	}

	imageJSON := image.Image{
		V1Image: base,
		History: []image.History{image.History{Created: t}},
		RootFS: &image.RootFS{
			Type:    "layers",
			DiffIDs: []layer.DiffID{layer.DiffID(digest)},
		},
	}

	js, err := imageJSON.MarshalJSON()
	if err != nil {
//.........这里部分代码省略.........

// CreateImageConfig constructs the image metadata from layers that compose the image
func CreateImageConfig(images []*ImageWithMeta, manifest *Manifest) error {

	if len(images) == 0 {
		return nil
	}

	imageLayer := images[0] // the layer that represents the actual image
	image := docker.V1Image{}
	rootFS := docker.NewRootFS()
	history := make([]docker.History, 0, len(images))
	diffIDs := make(map[string]string)
	var size int64

	// step through layers to get command history and diffID from oldest to newest
	for i := len(images) - 1; i >= 0; i-- {
		layer := images[i]
		if err := json.Unmarshal([]byte(layer.meta), &image); err != nil {
			return fmt.Errorf("Failed to unmarshall layer history: %s", err)
		}
		h := docker.History{
			Created:   image.Created,
			Author:    image.Author,
			CreatedBy: strings.Join(image.ContainerConfig.Cmd, " "),
			Comment:   image.Comment,
		}
		history = append(history, h)
		rootFS.DiffIDs = append(rootFS.DiffIDs, dockerLayer.DiffID(layer.diffID))
		diffIDs[layer.diffID] = layer.ID
		size += layer.size
	}

	// result is constructed without unused fields
	result := docker.Image{
		V1Image: docker.V1Image{
			Comment:         image.Comment,
			Created:         image.Created,
			Container:       image.Container,
			ContainerConfig: image.ContainerConfig,
			DockerVersion:   image.DockerVersion,
			Author:          image.Author,
			Config:          image.Config,
			Architecture:    image.Architecture,
			OS:              image.OS,
		},
		RootFS:  rootFS,
		History: history,
	}

	bytes, err := result.MarshalJSON()
	if err != nil {
		return fmt.Errorf("Failed to marshall image metadata: %s", err)
	}

	// calculate image ID
	sum := fmt.Sprintf("%x", sha256.Sum256(bytes))
	log.Infof("Image ID: sha256:%s", sum)

	// prepare metadata
	result.V1Image.Parent = image.Parent
	result.Size = size
	result.V1Image.ID = imageLayer.ID
	metaData := metadata.ImageConfig{
		V1Image: result.V1Image,
		ImageID: sum,
		// TODO: this will change when issue 1186 is
		// implemented -- only populate the digests when pulled by digest
		Digests: []string{manifest.Digest},
		Tags:    []string{options.tag},
		Name:    manifest.Name,
		DiffIDs: diffIDs,
		History: history,
	}

	blob, err := json.Marshal(metaData)
	if err != nil {
		return fmt.Errorf("Failed to marshal image metadata: %s", err)
	}

	// store metadata
	imageLayer.meta = string(blob)

	return nil
}

// CreateImageConfig constructs the image metadata from layers that compose the image
func (ic *ImageC) CreateImageConfig(images []*ImageWithMeta) (metadata.ImageConfig, error) {

	imageLayer := images[0] // the layer that represents the actual image

	// if we already have an imageID associated with this layerID, we don't need
	// to calculate imageID and can just grab the image config from the cache
	id := cache.RepositoryCache().GetImageID(imageLayer.ID)
	if image, err := cache.ImageCache().Get(id); err == nil {
		return *image, nil
	}

	manifest := ic.ImageManifest
	image := docker.V1Image{}
	rootFS := docker.NewRootFS()
	history := make([]docker.History, 0, len(images))
	diffIDs := make(map[string]string)
	var size int64

	// step through layers to get command history and diffID from oldest to newest
	for i := len(images) - 1; i >= 0; i-- {
		layer := images[i]
		if err := json.Unmarshal([]byte(layer.Meta), &image); err != nil {
			return metadata.ImageConfig{}, fmt.Errorf("Failed to unmarshall layer history: %s", err)
		}
		h := docker.History{
			Created:   image.Created,
			Author:    image.Author,
			CreatedBy: strings.Join(image.ContainerConfig.Cmd, " "),
			Comment:   image.Comment,
		}
		history = append(history, h)
		rootFS.DiffIDs = append(rootFS.DiffIDs, dockerLayer.DiffID(layer.DiffID))
		diffIDs[layer.DiffID] = layer.ID
		size += layer.Size
	}

	// result is constructed without unused fields
	result := docker.Image{
		V1Image: docker.V1Image{
			Comment:         image.Comment,
			Created:         image.Created,
			Container:       image.Container,
			ContainerConfig: image.ContainerConfig,
			DockerVersion:   image.DockerVersion,
			Author:          image.Author,
			Config:          image.Config,
			Architecture:    image.Architecture,
			OS:              image.OS,
		},
		RootFS:  rootFS,
		History: history,
	}

	bytes, err := result.MarshalJSON()
	if err != nil {
		return metadata.ImageConfig{}, fmt.Errorf("Failed to marshall image metadata: %s", err)
	}

	// calculate image ID
	sum := fmt.Sprintf("%x", sha256.Sum256(bytes))
	log.Infof("Image ID: sha256:%s", sum)

	// prepare metadata
	result.V1Image.Parent = image.Parent
	result.Size = size
	result.V1Image.ID = imageLayer.ID
	imageConfig := metadata.ImageConfig{
		V1Image: result.V1Image,
		ImageID: sum,
		// TODO: this will change when issue 1186 is
		// implemented -- only populate the digests when pulled by digest
		Digests:   []string{manifest.Digest},
		Tags:      []string{ic.Tag},
		Name:      manifest.Name,
		DiffIDs:   diffIDs,
		History:   history,
		Reference: ic.Reference,
	}

	return imageConfig, nil
}