blob: 09ce78b5dc1a6d5f2f4bb7eebab5c503cbb0c8fa [file] [log] [blame]
package ocischema
import (
var (
// SchemaVersion provides a pre-initialized version structure for this
// packages version of the manifest.
SchemaVersion = manifest.Versioned{
SchemaVersion: 2, // historical value here.. does not pertain to OCI or docker version
MediaType: v1.MediaTypeImageManifest,
func init() {
ocischemaFunc := func(b []byte) (distribution.Manifest, distribution.Descriptor, error) {
m := new(DeserializedManifest)
err := m.UnmarshalJSON(b)
if err != nil {
return nil, distribution.Descriptor{}, err
dgst := digest.FromBytes(b)
return m, distribution.Descriptor{Digest: dgst, Size: int64(len(b)), MediaType: v1.MediaTypeImageManifest}, err
err := distribution.RegisterManifestSchema(v1.MediaTypeImageManifest, ocischemaFunc)
if err != nil {
panic(fmt.Sprintf("Unable to register manifest: %s", err))
// Manifest defines a ocischema manifest.
type Manifest struct {
// Config references the image configuration as a blob.
Config distribution.Descriptor `json:"config"`
// Layers lists descriptors for the layers referenced by the
// configuration.
Layers []distribution.Descriptor `json:"layers"`
// Annotations contains arbitrary metadata for the image manifest.
Annotations map[string]string `json:"annotations,omitempty"`
// References returns the descriptors of this manifests references.
func (m Manifest) References() []distribution.Descriptor {
references := make([]distribution.Descriptor, 0, 1+len(m.Layers))
references = append(references, m.Config)
references = append(references, m.Layers...)
return references
// Target returns the target of this manifest.
func (m Manifest) Target() distribution.Descriptor {
return m.Config
// DeserializedManifest wraps Manifest with a copy of the original JSON.
// It satisfies the distribution.Manifest interface.
type DeserializedManifest struct {
// canonical is the canonical byte representation of the Manifest.
canonical []byte
// FromStruct takes a Manifest structure, marshals it to JSON, and returns a
// DeserializedManifest which contains the manifest and its JSON representation.
func FromStruct(m Manifest) (*DeserializedManifest, error) {
var deserialized DeserializedManifest
deserialized.Manifest = m
var err error
deserialized.canonical, err = json.MarshalIndent(&m, "", " ")
return &deserialized, err
// UnmarshalJSON populates a new Manifest struct from JSON data.
func (m *DeserializedManifest) UnmarshalJSON(b []byte) error {
m.canonical = make([]byte, len(b), len(b))
// store manifest in canonical
copy(m.canonical, b)
// Unmarshal canonical JSON into Manifest object
var manifest Manifest
if err := json.Unmarshal(m.canonical, &manifest); err != nil {
return err
if manifest.MediaType != "" && manifest.MediaType != v1.MediaTypeImageManifest {
return fmt.Errorf("if present, mediaType in manifest should be '%s' not '%s'",
v1.MediaTypeImageManifest, manifest.MediaType)
m.Manifest = manifest
return nil
// MarshalJSON returns the contents of canonical. If canonical is empty,
// marshals the inner contents.
func (m *DeserializedManifest) MarshalJSON() ([]byte, error) {
if len(m.canonical) > 0 {
return m.canonical, nil
return nil, errors.New("JSON representation not initialized in DeserializedManifest")
// Payload returns the raw content of the manifest. The contents can be used to
// calculate the content identifier.
func (m DeserializedManifest) Payload() (string, []byte, error) {
return v1.MediaTypeImageManifest, m.canonical, nil