package distribution import ( "context" "fmt" "mime" "github.com/opencontainers/go-digest" ) // Manifest represents a registry object specifying a set of // references and an optional target type Manifest interface { // References returns a list of objects which make up this manifest. // A reference is anything which can be represented by a // distribution.Descriptor. These can consist of layers, resources or other // manifests. // // While no particular order is required, implementations should return // them from highest to lowest priority. For example, one might want to // return the base layer before the top layer. References() []Descriptor // Payload provides the serialized format of the manifest, in addition to // the media type. Payload() (mediaType string, payload []byte, err error) } // ManifestBuilder creates a manifest allowing one to include dependencies. // Instances can be obtained from a version-specific manifest package. Manifest // specific data is passed into the function which creates the builder. type ManifestBuilder interface { // Build creates the manifest from his builder. Build(ctx context.Context) (Manifest, error) // References returns a list of objects which have been added to this // builder. The dependencies are returned in the order they were added, // which should be from base to head. References() []Descriptor // AppendReference includes the given object in the manifest after any // existing dependencies. If the add fails, such as when adding an // unsupported dependency, an error may be returned. // // The destination of the reference is dependent on the manifest type and // the dependency type. AppendReference(dependency Describable) error } // ManifestService describes operations on manifests. type ManifestService interface { // Exists returns true if the manifest exists. Exists(ctx context.Context, dgst digest.Digest) (bool, error) // Get retrieves the manifest specified by the given digest Get(ctx context.Context, dgst digest.Digest, options ...ManifestServiceOption) (Manifest, error) // Put creates or updates the given manifest returning the manifest digest Put(ctx context.Context, manifest Manifest, options ...ManifestServiceOption) (digest.Digest, error) // Delete removes the manifest specified by the given digest. Deleting // a manifest that doesn't exist will return ErrManifestNotFound Delete(ctx context.Context, dgst digest.Digest) error } // ManifestEnumerator enables iterating over manifests type ManifestEnumerator interface { // Enumerate calls ingester for each manifest. Enumerate(ctx context.Context, ingester func(digest.Digest) error) error } // Describable is an interface for descriptors type Describable interface { Descriptor() Descriptor } // ManifestMediaTypes returns the supported media types for manifests. func ManifestMediaTypes() (mediaTypes []string) { for t := range mappings { if t != "" { mediaTypes = append(mediaTypes, t) } } return } // UnmarshalFunc implements manifest unmarshalling a given MediaType type UnmarshalFunc func([]byte) (Manifest, Descriptor, error) var mappings = make(map[string]UnmarshalFunc) // UnmarshalManifest looks up manifest unmarshal functions based on // MediaType func UnmarshalManifest(ctHeader string, p []byte) (Manifest, Descriptor, error) { // Need to look up by the actual media type, not the raw contents of // the header. Strip semicolons and anything following them. var mediaType string if ctHeader != "" { var err error mediaType, _, err = mime.ParseMediaType(ctHeader) if err != nil { return nil, Descriptor{}, err } } unmarshalFunc, ok := mappings[mediaType] if !ok { unmarshalFunc, ok = mappings[""] if !ok { return nil, Descriptor{}, fmt.Errorf("unsupported manifest media type and no default available: %s", mediaType) } } return unmarshalFunc(p) } // RegisterManifestSchema registers an UnmarshalFunc for a given schema type. This // should be called from specific func RegisterManifestSchema(mediaType string, u UnmarshalFunc) error { if _, ok := mappings[mediaType]; ok { return fmt.Errorf("manifest media type registration would overwrite existing: %s", mediaType) } mappings[mediaType] = u return nil }