Return the full list of descriptors in build metadata

Signed-off-by: Laurent Goderre <[email protected]>

cmd/buildctl/build.go

@@ -439,8 +439,11 @@ func writeMetadataFile(filename string, exporterResponse map[string]string) erro
 		}
 		var raw map[string]interface{}
 		if err = json.Unmarshal(dt, &raw); err != nil || len(raw) == 0 {
-			out[k] = v
-			continue
+			var rawList []map[string]interface{}
+			if err = json.Unmarshal(dt, &rawList); err != nil || len(rawList) == 0 {
+				out[k] = v
+				continue
+			}
 		}
 		out[k] = json.RawMessage(dt)
 	}

cmd/buildctl/build_test.go

@@ -140,7 +140,7 @@ func testBuildMetadataFile(t *testing.T, sb integration.Sandbox) {
 	metadataBytes, err := os.ReadFile(metadataFile)
 	require.NoError(t, err)
 
-	var metadata map[string]interface{}
+	var metadata map[string]json.RawMessage
 	err = json.Unmarshal(metadataBytes, &metadata)
 	require.NoError(t, err)
 
@@ -153,13 +153,17 @@ func testBuildMetadataFile(t *testing.T, sb integration.Sandbox) {
 
 	require.Contains(t, metadata, exptypes.ExporterImageDescriptorKey)
 	var desc *ocispecs.Descriptor
-	dtdesc, err := json.Marshal(metadata[exptypes.ExporterImageDescriptorKey])
-	require.NoError(t, err)
-	err = json.Unmarshal(dtdesc, &desc)
+	err = json.Unmarshal(metadata[exptypes.ExporterImageDescriptorKey], &desc)
 	require.NoError(t, err)
 	require.NotEmpty(t, desc.MediaType)
 	require.NotEmpty(t, desc.Digest.String())
 
+	require.Contains(t, metadata, exptypes.ExporterImageDescriptorsKey)
+	var descList []*ocispecs.Descriptor
+	require.NoError(t, err)
+	err = json.Unmarshal(metadata[exptypes.ExporterImageDescriptorsKey], &descList)
+	require.NoError(t, err)
+
 	cdAddress := sb.ContainerdAddress()
 	if cdAddress == "" {
 		t.Log("no containerd worker, skipping digest verification")

exporter/containerimage/export.go

@@ -230,10 +230,11 @@ func (e *imageExporterInstance) Export(ctx context.Context, src *exporter.Source
 		}
 	}()
 
-	desc, err := e.opt.ImageWriter.Commit(ctx, src, sessionID, inlineCache, &opts)
+	descriptors, err := e.opt.ImageWriter.Commit(ctx, src, sessionID, inlineCache, &opts)
 	if err != nil {
 		return nil, nil, err
 	}
+	desc := descriptors[0]
 	defer func() {
 		if err == nil {
 			descref = NewDescriptorReference(*desc, done)
@@ -359,6 +360,12 @@ func (e *imageExporterInstance) Export(ctx context.Context, src *exporter.Source
 	}
 	resp[exptypes.ExporterImageDescriptorKey] = base64.StdEncoding.EncodeToString(dtdesc)
 
+	dtdesclist, err := json.Marshal(descriptors)
+	if err != nil {
+		return nil, nil, err
+	}
+	resp[exptypes.ExporterImageDescriptorsKey] = base64.StdEncoding.EncodeToString(dtdesclist)
+
 	return resp, nil, nil
 }
 

exporter/containerimage/exptypes/types.go

@@ -13,6 +13,7 @@ const (
 	ExporterImageConfigKey       = "containerimage.config"
 	ExporterImageConfigDigestKey = "containerimage.config.digest"
 	ExporterImageDescriptorKey   = "containerimage.descriptor"
+	ExporterImageDescriptorsKey  = "containerimage.descriptors"
 	ExporterImageBaseConfigKey   = "containerimage.base.config"
 	ExporterPlatformsKey         = "refs.platforms"
 )

exporter/containerimage/writer.go

@@ -61,7 +61,7 @@ type ImageWriter struct {
 	opt WriterOpt
 }
 
-func (ic *ImageWriter) Commit(ctx context.Context, inp *exporter.Source, sessionID string, inlineCache exptypes.InlineCache, opts *ImageCommitOpts) (*ocispecs.Descriptor, error) {
+func (ic *ImageWriter) Commit(ctx context.Context, inp *exporter.Source, sessionID string, inlineCache exptypes.InlineCache, opts *ImageCommitOpts) ([]*ocispecs.Descriptor, error) {
 	if _, ok := inp.Metadata[exptypes.ExporterPlatformsKey]; len(inp.Refs) > 0 && !ok {
 		return nil, errors.Errorf("unable to export multiple refs, missing platforms mapping")
 	}
@@ -180,7 +180,10 @@ func (ic *ImageWriter) Commit(ctx context.Context, inp *exporter.Source, session
 		}
 		mfstDesc.Annotations[exptypes.ExporterConfigDigestKey] = configDesc.Digest.String()
 
-		return mfstDesc, nil
+		return []*ocispecs.Descriptor{
+			mfstDesc,
+			configDesc,
+		}, nil
 	}
 
 	if len(inp.Attestations) > 0 {
@@ -225,6 +228,7 @@ func (ic *ImageWriter) Commit(ctx context.Context, inp *exporter.Source, session
 
 	labels := map[string]string{}
 
+	var descriptors []*ocispecs.Descriptor
 	var attestationManifests []ocispecs.Descriptor
 
 	for i, p := range ps.Platforms {
@@ -261,15 +265,16 @@ func (ic *ImageWriter) Commit(ctx context.Context, inp *exporter.Source, session
 			inlineCacheEntry, _ = inlineCacheResult.FindRef(p.ID)
 		}
 
-		desc, _, err := ic.commitDistributionManifest(ctx, opts, r, config, remote, opts.Annotations.Platform(&p.Platform), inlineCacheEntry, opts.Epoch, session.NewGroup(sessionID), baseImg)
+		mfstDesc, configDesc, err := ic.commitDistributionManifest(ctx, opts, r, config, remote, opts.Annotations.Platform(&p.Platform), inlineCacheEntry, opts.Epoch, session.NewGroup(sessionID), baseImg)
 		if err != nil {
 			return nil, err
 		}
 		dp := p.Platform
-		desc.Platform = &dp
-		idx.Manifests = append(idx.Manifests, *desc)
+		mfstDesc.Platform = &dp
+		idx.Manifests = append(idx.Manifests, *mfstDesc)
+		descriptors = append(descriptors, mfstDesc, configDesc)
 
-		labels[fmt.Sprintf("containerd.io/gc.ref.content.%d", i)] = desc.Digest.String()
+		labels[fmt.Sprintf("containerd.io/gc.ref.content.%d", i)] = mfstDesc.Digest.String()
 
 		if attestations, ok := inp.Attestations[p.ID]; ok {
 			attestations, err := attestation.Unbundle(ctx, session.NewGroup(sessionID), attestations)
@@ -304,15 +309,15 @@ func (ic *ImageWriter) Commit(ctx context.Context, inp *exporter.Source, session
 				}
 				defaultSubjects = append(defaultSubjects, intoto.Subject{
 					Name:   pl,
-					Digest: result.ToDigestMap(desc.Digest),
+					Digest: result.ToDigestMap(mfstDesc.Digest),
 				})
 			}
 			stmts, err := attestation.MakeInTotoStatements(ctx, session.NewGroup(sessionID), attestations, defaultSubjects)
 			if err != nil {
 				return nil, err
 			}
 
-			desc, err := ic.commitAttestationsManifest(ctx, opts, desc.Digest.String(), stmts)
+			desc, err := ic.commitAttestationsManifest(ctx, opts, mfstDesc.Digest.String(), stmts)
 			if err != nil {
 				return nil, err
 			}
@@ -323,6 +328,7 @@ func (ic *ImageWriter) Commit(ctx context.Context, inp *exporter.Source, session
 
 	for i, mfst := range attestationManifests {
 		idx.Manifests = append(idx.Manifests, mfst)
+		descriptors = append(descriptors, &mfst)
 		labels[fmt.Sprintf("containerd.io/gc.ref.content.%d", len(ps.Platforms)+i)] = mfst.Digest.String()
 	}
 
@@ -344,8 +350,9 @@ func (ic *ImageWriter) Commit(ctx context.Context, inp *exporter.Source, session
 		return nil, idxDone(errors.Wrapf(err, "error writing manifest list blob %s", idxDigest))
 	}
 	idxDone(nil)
+	descriptors = append([]*ocispecs.Descriptor{&idxDesc}, descriptors...)
 
-	return &idxDesc, nil
+	return descriptors, nil
 }
 
 func (ic *ImageWriter) exportLayers(ctx context.Context, refCfg cacheconfig.RefConfig, s session.Group, refs ...cache.ImmutableRef) ([]solver.Remote, error) {

exporter/oci/export.go

@@ -159,10 +159,11 @@ func (e *imageExporterInstance) Export(ctx context.Context, src *exporter.Source
 		}
 	}()
 
-	desc, err := e.opt.ImageWriter.Commit(ctx, src, sessionID, inlineCache, &opts)
+	descriptors, err := e.opt.ImageWriter.Commit(ctx, src, sessionID, inlineCache, &opts)
 	if err != nil {
 		return nil, nil, err
 	}
+	desc := descriptors[0]
 	defer func() {
 		if err == nil {
 			descref = containerimage.NewDescriptorReference(*desc, done)
@@ -194,6 +195,12 @@ func (e *imageExporterInstance) Export(ctx context.Context, src *exporter.Source
 	}
 	resp[exptypes.ExporterImageDescriptorKey] = base64.StdEncoding.EncodeToString(dtdesc)
 
+	dtdesclist, err := json.Marshal(descriptors)
+	if err != nil {
+		return nil, nil, err
+	}
+	resp[exptypes.ExporterImageDescriptorsKey] = base64.StdEncoding.EncodeToString(dtdesclist)
+
 	if n, ok := src.Metadata["image.name"]; e.opts.ImageName == "*" && ok {
 		e.opts.ImageName = string(n)
 	}