Function Children

core/images/image.go:337–377

Children returns the immediate children of content described by the descriptor.

(ctx context.Context, provider content.Provider, desc ocispec.Descriptor)

// Children returns the immediate children of content described by the descriptor.
func Children(ctx context.Context, provider content.Provider, desc ocispec.Descriptor) ([]ocispec.Descriptor, error) {
	if IsManifestType(desc.MediaType) {
		p, err := content.ReadBlob(ctx, provider, desc)
		if err != nil {
			return nil, err
		}

		if err := validateMediaType(p, desc.MediaType); err != nil {
			return nil, fmt.Errorf("children: invalid desc %s: %w", desc.Digest, err)
		}

		// TODO(stevvooe): We just assume oci manifest, for now. There may be
		// subtle differences from the docker version.
		var manifest ocispec.Manifest
		if err := json.Unmarshal(p, &manifest); err != nil {
			return nil, err
		}

		return append([]ocispec.Descriptor{manifest.Config}, manifest.Layers...), nil
	} else if IsIndexType(desc.MediaType) {
		p, err := content.ReadBlob(ctx, provider, desc)
		if err != nil {
			return nil, err
		}

		if err := validateMediaType(p, desc.MediaType); err != nil {
			return nil, fmt.Errorf("children: invalid desc %s: %w", desc.Digest, err)
		}

		var index ocispec.Index
		if err := json.Unmarshal(p, &index); err != nil {
			return nil, err
		}

		return append([]ocispec.Descriptor{}, index.Manifests...), nil
	} else if !IsLayerType(desc.MediaType) && !IsKnownConfig(desc.MediaType) && !IsAttestationType(desc.MediaType) {
		// Layers, configs, and attestations are childless data types and should not be logged.
		log.G(ctx).Debugf("encountered unknown type %v; children may not be fetched", desc.MediaType)
	}
	return nil, nil
}

// unknownDocument represents a manifest, manifest list, or index that has not
// yet been validated.