Allow overriding the manifestdescriptor when pushing (#133)

pkg/oras/push.go

@@ -83,6 +83,10 @@ func pack(provider content.Provider, descriptors []ocispec.Descriptor, opts *pus
 	}
 
 	// Manifest
+	if opts.manifest != nil {
+		return *opts.manifest, store, nil
+	}
+
 	manifest := ocispec.Manifest{
 		Versioned: specs.Versioned{
 			SchemaVersion: 2, // historical value. does not pertain to OCI or docker version

pkg/oras/push_opts.go

@@ -15,6 +15,7 @@ type pushOpts struct {
 	config              *ocispec.Descriptor
 	configMediaType     string
 	configAnnotations   map[string]string
+	manifest            *ocispec.Descriptor
 	manifestAnnotations map[string]string
 	validateName        func(desc ocispec.Descriptor) error
 	baseHandlers        []images.Handler
@@ -29,7 +30,7 @@ func pushOptsDefaults() *pushOpts {
 // PushOpt allows callers to set options on the oras push
 type PushOpt func(o *pushOpts) error
 
-// WithConfig overrides the config
+// WithConfig overrides the config - setting this will ignore WithConfigMediaType and WithConfigAnnotations
 func WithConfig(config ocispec.Descriptor) PushOpt {
 	return func(o *pushOpts) error {
 		o.config = &config
@@ -53,6 +54,14 @@ func WithConfigAnnotations(annotations map[string]string) PushOpt {
 	}
 }
 
+// WithManifest overrides the manifest - setting this will ignore WithManifestConfigAnnotations
+func WithManifest(manifest ocispec.Descriptor) PushOpt {
+	return func(o *pushOpts) error {
+		o.manifest = &manifest
+		return nil
+	}
+}
+
 // WithManifestAnnotations overrides the manifest annotations
 func WithManifestAnnotations(annotations map[string]string) PushOpt {
 	return func(o *pushOpts) error {