package ocischema import ( "context" "errors" "github.com/docker/distribution" "github.com/docker/distribution/manifest" "github.com/opencontainers/go-digest" "github.com/opencontainers/image-spec/specs-go/v1" ) // Builder is a type for constructing manifests. type Builder struct { // bs is a BlobService used to publish the configuration blob. bs distribution.BlobService // configJSON references configJSON []byte // layers is a list of layer descriptors that gets built by successive // calls to AppendReference. layers []distribution.Descriptor // Annotations contains arbitrary metadata relating to the targeted content. annotations map[string]string // For testing purposes mediaType string } // NewManifestBuilder is used to build new manifests for the current schema // version. It takes a BlobService so it can publish the configuration blob // as part of the Build process, and annotations. func NewManifestBuilder(bs distribution.BlobService, configJSON []byte, annotations map[string]string) distribution.ManifestBuilder { mb := &Builder{ bs: bs, configJSON: make([]byte, len(configJSON)), annotations: annotations, mediaType: v1.MediaTypeImageManifest, } copy(mb.configJSON, configJSON) return mb } // SetMediaType assigns the passed mediatype or error if the mediatype is not a // valid media type for oci image manifests currently: "" or "application/vnd.oci.image.manifest.v1+json" func (mb *Builder) SetMediaType(mediaType string) error { if mediaType != "" && mediaType != v1.MediaTypeImageManifest { return errors.New("invalid media type for OCI image manifest") } mb.mediaType = mediaType return nil } // Build produces a final manifest from the given references. func (mb *Builder) Build(ctx context.Context) (distribution.Manifest, error) { m := Manifest{ Versioned: manifest.Versioned{ SchemaVersion: 2, MediaType: mb.mediaType, }, Layers: make([]distribution.Descriptor, len(mb.layers)), Annotations: mb.annotations, } copy(m.Layers, mb.layers) configDigest := digest.FromBytes(mb.configJSON) var err error m.Config, err = mb.bs.Stat(ctx, configDigest) switch err { case nil: // Override MediaType, since Put always replaces the specified media // type with application/octet-stream in the descriptor it returns. m.Config.MediaType = v1.MediaTypeImageConfig return FromStruct(m) case distribution.ErrBlobUnknown: // nop default: return nil, err } // Add config to the blob store m.Config, err = mb.bs.Put(ctx, v1.MediaTypeImageConfig, mb.configJSON) // Override MediaType, since Put always replaces the specified media // type with application/octet-stream in the descriptor it returns. m.Config.MediaType = v1.MediaTypeImageConfig if err != nil { return nil, err } return FromStruct(m) } // AppendReference adds a reference to the current ManifestBuilder. func (mb *Builder) AppendReference(d distribution.Describable) error { mb.layers = append(mb.layers, d.Descriptor()) return nil } // References returns the current references added to this builder. func (mb *Builder) References() []distribution.Descriptor { return mb.layers }