refactor: expose descriptor for image/index

pkg/sif/image.go

@@ -46,6 +46,11 @@ func (im *image) RawManifest() ([]byte, error) {
 	return im.rawManifest, nil
 }
 
+// Descriptor returns the original descriptor from an index manifest. See partial.Descriptor.
+func (im *image) Descriptor() (*v1.Descriptor, error) {
+	return im.desc, nil
+}
+
 var errLayerNotFoundInImage = errors.New("layer not found in image")
 
 // LayerByDigest returns a Layer for interacting with a particular layer of the image, looking it

pkg/sif/image_test.go

@@ -5,46 +5,79 @@
 package sif_test
 
 import (
+	"reflect"
 	"testing"
 
 	v1 "github.com/google/go-containerregistry/pkg/v1"
+	"github.com/google/go-containerregistry/pkg/v1/partial"
 	"github.com/google/go-containerregistry/pkg/v1/validate"
+	"github.com/sylabs/oci-tools/pkg/sif"
 )
 
-func TestFile_Image(t *testing.T) {
+// imageIndexFromPath returns an ImageIndex for the test to use, populated from the OCI Image
+// Layout with the specified path in the corpus.
+func imageIndexFromPath(t *testing.T, path string) v1.ImageIndex {
+	t.Helper()
+
+	ii, err := sif.ImageIndexFromFileImage(fileImageFromPath(t, path))
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	return ii
+}
+
+func Test_imageIndex_Image(t *testing.T) {
+	imageDigest := v1.Hash{
+		Algorithm: "sha256",
+		Hex:       "432f982638b3aefab73cc58ab28f5c16e96fdb504e8c134fc58dff4bae8bf338",
+	}
+	imageDescriptor := &v1.Descriptor{
+		MediaType: "application/vnd.docker.distribution.manifest.v2+json",
+		Size:      525,
+		Digest:    imageDigest,
+		Platform: &v1.Platform{
+			Architecture: "arm64",
+			OS:           "linux",
+			Variant:      "v8",
+		},
+	}
+
 	tests := []struct {
-		name string
-		path string
-		hash v1.Hash
+		name           string
+		ii             v1.ImageIndex
+		hash           v1.Hash
+		wantErr        bool
+		wantDescriptor *v1.Descriptor
 	}{
 		{
-			name: "DockerManifest",
-			path: corpus.SIF(t, "hello-world-docker-v2-manifest"),
-			hash: v1.Hash{
-				Algorithm: "sha256",
-				Hex:       "432f982638b3aefab73cc58ab28f5c16e96fdb504e8c134fc58dff4bae8bf338",
-			},
+			name:           "DockerManifest",
+			ii:             imageIndexFromPath(t, "hello-world-docker-v2-manifest"),
+			hash:           imageDigest,
+			wantDescriptor: imageDescriptor,
 		},
 		{
-			name: "DockerManifestList",
-			path: corpus.SIF(t, "hello-world-docker-v2-manifest-list"),
-			hash: v1.Hash{
-				Algorithm: "sha256",
-				Hex:       "432f982638b3aefab73cc58ab28f5c16e96fdb504e8c134fc58dff4bae8bf338",
-			},
+			name:           "DockerManifestList",
+			ii:             imageIndexFromPath(t, "hello-world-docker-v2-manifest-list"),
+			hash:           imageDigest,
+			wantDescriptor: imageDescriptor,
 		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			ii := imageIndexFromPath(t, tt.path)
-
-			img, err := ii.Image(tt.hash)
+			img, err := tt.ii.Image(tt.hash)
 			if err != nil {
 				t.Fatal(err)
 			}
 
 			if err := validate.Image(img); err != nil {
-				t.Fatal(err)
+				t.Error(err)
+			}
+
+			if d, err := partial.Descriptor(img); err != nil {
+				t.Error(err)
+			} else if got, want := d, tt.wantDescriptor; !reflect.DeepEqual(got, want) {
+				t.Errorf("got descriptor %+v, want %+v", got, want)
 			}
 		})
 	}

pkg/sif/index.go

@@ -5,6 +5,7 @@
 package sif
 
 import (
+	"bytes"
 	"encoding/json"
 	"errors"
 	"fmt"
@@ -26,7 +27,7 @@ func ImageIndexFromFileImage(fi *sif.FileImage) (v1.ImageIndex, error) {
 
 type imageIndex struct {
 	f           *fileImage
-	mediaType   types.MediaType
+	desc        *v1.Descriptor
 	rawManifest []byte
 }
 
@@ -44,26 +45,35 @@ func (f *fileImage) ImageIndex() (v1.ImageIndex, error) {
 		return nil, err
 	}
 
+	digest, size, err := v1.SHA256(bytes.NewReader(b))
+	if err != nil {
+		return nil, err
+	}
+
 	return &imageIndex{
-		f:           f,
-		mediaType:   types.OCIImageIndex,
+		f: f,
+		desc: &v1.Descriptor{
+			MediaType: types.OCIImageIndex,
+			Size:      size,
+			Digest:    digest,
+		},
 		rawManifest: b,
 	}, nil
 }
 
 // MediaType of this image's manifest.
 func (ix *imageIndex) MediaType() (types.MediaType, error) {
-	return ix.mediaType, nil
+	return ix.desc.MediaType, nil
 }
 
 // Digest returns the sha256 of this index's manifest.
 func (ix *imageIndex) Digest() (v1.Hash, error) {
-	return partial.Digest(ix)
+	return ix.desc.Digest, nil
 }
 
 // Size returns the size of the manifest.
 func (ix *imageIndex) Size() (int64, error) {
-	return partial.Size(ix)
+	return ix.desc.Size, nil
 }
 
 // IndexManifest returns this image index's manifest object.
@@ -78,6 +88,11 @@ func (ix *imageIndex) RawManifest() ([]byte, error) {
 	return ix.rawManifest, nil
 }
 
+// Descriptor returns the original descriptor from an index manifest. See partial.Descriptor.
+func (ix *imageIndex) Descriptor() (*v1.Descriptor, error) {
+	return ix.desc, nil
+}
+
 var errUnexpectedMediaType = errors.New("unexpected media type")
 
 // Image returns a v1.Image that this ImageIndex references.
@@ -96,12 +111,12 @@ func (ix *imageIndex) Image(h v1.Hash) (v1.Image, error) {
 		return nil, err
 	}
 
-	img := &image{
+	img := image{
 		f:           ix.f,
 		desc:        desc,
 		rawManifest: b,
 	}
-	return partial.CompressedToImage(img)
+	return partial.CompressedToImage(&img)
 }
 
 // ImageIndex returns a v1.ImageIndex that this ImageIndex references.
@@ -122,8 +137,8 @@ func (ix *imageIndex) ImageIndex(h v1.Hash) (v1.ImageIndex, error) {
 
 	return &imageIndex{
 		f:           ix.f,
+		desc:        desc,
 		rawManifest: b,
-		mediaType:   desc.MediaType,
 	}, nil
 }
 

pkg/sif/index_test.go

@@ -5,6 +5,7 @@
 package sif_test
 
 import (
+	"reflect"
 	"testing"
 
 	v1 "github.com/google/go-containerregistry/pkg/v1"
@@ -13,43 +14,71 @@ import (
 	ssif "github.com/sylabs/sif/v2/pkg/sif"
 )
 
-func imageIndexFromPath(t *testing.T, path string) v1.ImageIndex {
+type withDescriptor interface {
+	Descriptor() (*v1.Descriptor, error)
+}
+
+// fileImageFromPath returns a temporary FileImage for the test to use, populated from the OCI
+// Image Layout with the specified path in the corpus. The FileImage is automatically unloaded when
+// the test and all its subtests complete.
+func fileImageFromPath(t *testing.T, path string) *ssif.FileImage {
 	t.Helper()
 
-	f, err := ssif.LoadContainerFromPath(path)
+	f, err := ssif.LoadContainerFromPath(corpus.SIF(t, path))
 	if err != nil {
 		t.Fatal(err)
 	}
 	t.Cleanup(func() { _ = f.UnloadContainer() })
 
-	ii, err := sif.ImageIndexFromFileImage(f)
-	if err != nil {
-		t.Fatal(err)
-	}
-
-	return ii
+	return f
 }
 
-func TestFile_ImageIndex(t *testing.T) {
+func TestImageIndexFromFileImage(t *testing.T) {
 	tests := []struct {
-		name string
-		path string
+		name           string
+		f              *ssif.FileImage
+		wantDescriptor *v1.Descriptor
 	}{
 		{
 			name: "DockerManifest",
-			path: corpus.SIF(t, "hello-world-docker-v2-manifest"),
+			f:    fileImageFromPath(t, "hello-world-docker-v2-manifest"),
+			wantDescriptor: &v1.Descriptor{
+				MediaType: "application/vnd.oci.image.index.v1+json",
+				Size:      314,
+				Digest: v1.Hash{
+					Algorithm: "sha256",
+					Hex:       "a2ca8d2eb29d4b32cabd3f2ca67c14c8ae178b93c3000da3ec63faca49a688e4",
+				},
+			},
 		},
 		{
 			name: "DockerManifestList",
-			path: corpus.SIF(t, "hello-world-docker-v2-manifest-list"),
+			f:    fileImageFromPath(t, "hello-world-docker-v2-manifest-list"),
+			wantDescriptor: &v1.Descriptor{
+				MediaType: "application/vnd.oci.image.index.v1+json",
+				Size:      2069,
+				Digest: v1.Hash{
+					Algorithm: "sha256",
+					Hex:       "00e1ee7c898a2c393ea2fe7680938f8dcbe55e51fbf08032cf37326a677f92ed",
+				},
+			},
 		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			ii := imageIndexFromPath(t, tt.path)
+			ii, err := sif.ImageIndexFromFileImage(tt.f)
+			if err != nil {
+				t.Fatal(err)
+			}
 
 			if err := validate.Index(ii); err != nil {
-				t.Fatal(err)
+				t.Error(err)
+			}
+
+			if d, err := ii.(withDescriptor).Descriptor(); err != nil {
+				t.Error(err)
+			} else if got, want := d, tt.wantDescriptor; !reflect.DeepEqual(got, want) {
+				t.Errorf("got descriptor %+v, want %+v", got, want)
 			}
 		})
 	}

pkg/sif/layer.go

@@ -39,7 +39,7 @@ func (l *layer) MediaType() (types.MediaType, error) {
 	return l.desc.MediaType, nil
 }
 
-// Descriptor implements partial.withDescriptor.
+// Descriptor returns the original descriptor from an image manifest. See partial.Descriptor.
 func (l *layer) Descriptor() (*v1.Descriptor, error) {
 	return &l.desc, nil
 }

pkg/sif/layer_test.go

@@ -0,0 +1,76 @@
+// Copyright 2023 Sylabs Inc. All rights reserved.
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package sif_test
+
+import (
+	"reflect"
+	"testing"
+
+	v1 "github.com/google/go-containerregistry/pkg/v1"
+	"github.com/google/go-containerregistry/pkg/v1/partial"
+)
+
+// layerFromPath returns a Layer for the test to use, populated from the OCI Image with the
+// specified path/digests in the corpus.
+func layerFromPath(t *testing.T, path string, imageDigest, layerDigest string) v1.Layer {
+	t.Helper()
+
+	ii := imageIndexFromPath(t, path)
+
+	imageHash, err := v1.NewHash(imageDigest)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	img, err := ii.Image(imageHash)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	layerHash, err := v1.NewHash(layerDigest)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	l, err := img.LayerByDigest(layerHash)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	return l
+}
+
+func TestLayer_Descriptor(t *testing.T) {
+	tests := []struct {
+		name           string
+		l              v1.Layer
+		wantDescriptor *v1.Descriptor
+	}{
+		{
+			name: "DockerManifest",
+			l: layerFromPath(t, "hello-world-docker-v2-manifest",
+				"sha256:432f982638b3aefab73cc58ab28f5c16e96fdb504e8c134fc58dff4bae8bf338",
+				"sha256:7050e35b49f5e348c4809f5eff915842962cb813f32062d3bbdd35c750dd7d01",
+			),
+			wantDescriptor: &v1.Descriptor{
+				MediaType: "application/vnd.docker.image.rootfs.diff.tar.gzip",
+				Size:      3208,
+				Digest: v1.Hash{
+					Algorithm: "sha256",
+					Hex:       "7050e35b49f5e348c4809f5eff915842962cb813f32062d3bbdd35c750dd7d01",
+				},
+			},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if d, err := partial.Descriptor(tt.l); err != nil {
+				t.Error(err)
+			} else if got, want := d, tt.wantDescriptor; !reflect.DeepEqual(got, want) {
+				t.Errorf("got descriptor %+v, want %+v", got, want)
+			}
+		})
+	}
+}