libimage.ManifestList: add AddArtifact()

* Add a libimage.ManifestList.AddArtifact() method.
* Add IndexAnnotations and Subject to libimage.ManifestListAnnotateOptions,
  for setting annotations on the index itself, and the index's subject,
  respectively.
* In libimage/manifests.list.AddArtifact(), if the subject has an
  artifactType in its manifest, add its value to the subject descriptor.

Signed-off-by: Nalin Dahyabhai <nalin@redhat.com>

libimage/manifest_list.go

@@ -19,6 +19,7 @@ import (
  structcopier "github.com/jinzhu/copier"
  "github.com/opencontainers/go-digest"
  imgspecv1 "github.com/opencontainers/image-spec/specs-go/v1"
+ "golang.org/x/exp/maps"
  "golang.org/x/exp/slices"
 )
 
@@ -294,7 +295,7 @@ func (m *ManifestList) Inspect() (*define.ManifestListData, error) {
  return &inspectList, nil
 }
 
-// Options for adding a manifest list.
+// Options for adding an image or artifact to a manifest list.
 type ManifestListAddOptions struct {
  // Add all images to the list if the to-be-added image itself is a
  // manifest list.
@@ -371,6 +372,104 @@ func (m *ManifestList) Add(ctx context.Context, name string, options *ManifestLi
  return newDigest, nil
 }
 
+// Options for creating an artifact manifest for one or more files and adding
+// the artifact manifest to a manifest list.
+type ManifestListAddArtifactOptions struct {
+ // The artifactType to set in the artifact manifest.
+ Type *string `json:"artifact_type"`
+ // The mediaType to set in the config.MediaType field in the artifact manifest.
+ ConfigType string `json:"artifact_config_type"`
+ // Content to point to from the config field in the artifact manifest.
+ Config string `json:"artifact_config"`
+ // The mediaType to set in the layer descriptors in the artifact manifest.
+ LayerType string `json:"artifact_layer_type"`
+ // Whether or not to suppress the org.opencontainers.image.title annotation in layer descriptors.
+ ExcludeTitles bool `json:"exclude_layer_titles"`
+ // Annotations to set in the artifact manifest.
+ Annotations map[string]string `json:"annotations"`
+ // Subject to set in the artifact manifest.
+ Subject string `json:"subject"`
+}
+
+// Add adds one or more manifests to the manifest list and returns the digest
+// of the added instance.
+func (m *ManifestList) AddArtifact(ctx context.Context, options *ManifestListAddArtifactOptions, files ...string) (digest.Digest, error) {
+ if options == nil {
+ options = &ManifestListAddArtifactOptions{}
+ }
+ opts := manifests.AddArtifactOptions{
+ ManifestArtifactType: options.Type,
+ Annotations: maps.Clone(options.Annotations),
+ ExcludeTitles: options.ExcludeTitles,
+ }
+ if options.ConfigType != "" {
+ opts.ConfigDescriptor = &imgspecv1.Descriptor{
+ MediaType: options.ConfigType,
+ Digest: imgspecv1.DescriptorEmptyJSON.Digest,
+ Size: imgspecv1.DescriptorEmptyJSON.Size,
+ Data: slices.Clone(imgspecv1.DescriptorEmptyJSON.Data),
+ }
+ }
+ if options.Config != "" {
+ if opts.ConfigDescriptor == nil {
+ opts.ConfigDescriptor = &imgspecv1.Descriptor{
+ MediaType: imgspecv1.MediaTypeImageConfig,
+ }
+ }
+ opts.ConfigDescriptor.Digest = digest.FromString(options.Config)
+ opts.ConfigDescriptor.Size = int64(len(options.Config))
+ opts.ConfigDescriptor.Data = slices.Clone([]byte(options.Config))
+ }
+ if opts.ConfigDescriptor == nil {
+ empty := imgspecv1.DescriptorEmptyJSON
+ opts.ConfigDescriptor = &empty
+ }
+ if options.LayerType != "" {
+ opts.LayerMediaType = &options.LayerType
+ }
+ if options.Subject != "" {
+ ref, err := alltransports.ParseImageName(options.Subject)
+ if err != nil {
+ withDocker := fmt.Sprintf("%s://%s", docker.Transport.Name(), options.Subject)
+ ref, err = alltransports.ParseImageName(withDocker)
+ if err != nil {
+ image, _, err := m.image.runtime.LookupImage(options.Subject, &LookupImageOptions{ManifestList: true})
+ if err != nil {
+ return "", fmt.Errorf("locating subject for artifact manifest: %w", err)
+ }
+ ref = image.storageReference
+ }
+ }
+ opts.SubjectReference = ref
+ }
+
+ // Lock the image record where this list lives.
+ locker, err := manifests.LockerForImage(m.image.runtime.store, m.ID())
+ if err != nil {
+ return "", err
+ }
+ locker.Lock()
+ defer locker.Unlock()
+
+ systemContext := m.image.runtime.systemContextCopy()
+
+ // Make sure to reload the image from the containers storage to fetch
+ // the latest data (e.g., new or delete digests).
+ if err := m.reload(); err != nil {
+ return "", err
+ }
+ newDigest, err := m.list.AddArtifact(ctx, systemContext, opts, files...)
+ if err != nil {
+ return "", err
+ }
+
+ // Write the changes to disk.
+ if err := m.saveAndReload(); err != nil {
+ return "", err
+ }
+ return newDigest, nil
+}
+
 // Options for annotating a manifest list.
 type ManifestListAnnotateOptions struct {
  // Add the specified annotations to the added image.
@@ -387,10 +486,16 @@ type ManifestListAnnotateOptions struct {
  OSVersion string
  // Add the specified variant to the added image.
  Variant string
+ // Add the specified annotations to the index itself.
+ IndexAnnotations map[string]string
+ // Set the subject to which the index refers.
+ Subject string
 }
 
 // Annotate an image instance specified by `d` in the manifest list.
 func (m *ManifestList) AnnotateInstance(d digest.Digest, options *ManifestListAnnotateOptions) error {
+ ctx := context.Background()
+
  if options == nil {
  return nil
  }
@@ -430,6 +535,54 @@ func (m *ManifestList) AnnotateInstance(d digest.Digest, options *ManifestListAn
  return err
  }
  }
+ if len(options.IndexAnnotations) > 0 {
+ if err := m.list.SetAnnotations(nil, options.IndexAnnotations); err != nil {
+ return err
+ }
+ }
+ if options.Subject != "" {
+ ref, err := alltransports.ParseImageName(options.Subject)
+ if err != nil {
+ withDocker := fmt.Sprintf("%s://%s", docker.Transport.Name(), options.Subject)
+ ref, err = alltransports.ParseImageName(withDocker)
+ if err != nil {
+ image, _, err := m.image.runtime.LookupImage(options.Subject, &LookupImageOptions{ManifestList: true})
+ if err != nil {
+ return fmt.Errorf("locating subject for image index: %w", err)
+ }
+ ref = image.storageReference
+ }
+ }
+ src, err := ref.NewImageSource(ctx, &m.image.runtime.systemContext)
+ if err != nil {
+ return err
+ }
+ defer src.Close()
+ subjectManifestBytes, subjectManifestType, err := src.GetManifest(ctx, nil)
+ if err != nil {
+ return err
+ }
+ subjectManifestDigest, err := manifest.Digest(subjectManifestBytes)
+ if err != nil {
+ return err
+ }
+ var subjectArtifactType string
+ if !manifest.MIMETypeIsMultiImage(subjectManifestType) {
+ var subjectManifest imgspecv1.Manifest
+ if json.Unmarshal(subjectManifestBytes, &subjectManifest) == nil {
+ subjectArtifactType = subjectManifest.ArtifactType
+ }
+ }
+ descriptor := &imgspecv1.Descriptor{
+ MediaType: subjectManifestType,
+ ArtifactType: subjectArtifactType,
+ Digest: subjectManifestDigest,
+ Size: int64(len(subjectManifestBytes)),
+ }
+ if err := m.list.SetSubject(descriptor); err != nil {
+ return err
+ }
+ }
 
  // Write the changes to disk.
  return m.saveAndReload()