feat: support mounting blobs during copy

cmd/oras/internal/display/track/target.go

@@ -66,6 +66,13 @@ func NewTarget(t oras.GraphTarget, actionPrompt, donePrompt string, tty *os.File
 	return gt, nil
 }
 
+// Mount mounts a blob from a specified repository. This method is invoked only
+// by the `*remote.Repository` target.
+func (t *graphTarget) Mount(ctx context.Context, desc ocispec.Descriptor, fromRepo string, getContent func() (io.ReadCloser, error)) error {
+	mounter := t.GraphTarget.(registry.Mounter)
+	return mounter.Mount(ctx, desc, fromRepo, getContent)
+}
+
 // Push pushes the content to the base oras.GraphTarget with tracking.
 func (t *graphTarget) Push(ctx context.Context, expected ocispec.Descriptor, content io.Reader) error {
 	r, err := managedReader(content, expected, t.manager, t.actionPrompt, t.donePrompt)

cmd/oras/internal/display/track/target_test.go

@@ -25,6 +25,7 @@ import (
 	ocispec "github.com/opencontainers/image-spec/specs-go/v1"
 	"oras.land/oras-go/v2"
 	"oras.land/oras-go/v2/content/memory"
+	"oras.land/oras-go/v2/registry/remote"
 	"oras.land/oras/cmd/oras/internal/display/console/testutils"
 )
 
@@ -79,34 +80,7 @@ func Test_referenceGraphTarget_PushReference(t *testing.T) {
 	}
 }
 
-func Test_referenceGraphTarget_Prompt(t *testing.T) {
-	// prepare
-	pty, device, err := testutils.NewPty()
-	if err != nil {
-		t.Fatal(err)
-	}
-	defer device.Close()
-	content := []byte("test")
-	desc := ocispec.Descriptor{
-		MediaType: "application/octet-stream",
-		Digest:    digest.FromBytes(content),
-		Size:      int64(len(content)),
-	}
-	// test
-	prompt := "prompt"
-	target, err := NewTarget(memory.New(), "action", "done", device)
-	if err != nil {
-		t.Fatal(err)
-	}
-	m := target.(*graphTarget).manager
-	if err := target.Prompt(desc, prompt); err != nil {
-		t.Fatal(err)
-	}
-	if err := m.Close(); err != nil {
-		t.Fatal(err)
-	}
-	// validate
-	if err = testutils.MatchPty(pty, device, prompt, desc.MediaType, "100.00%", desc.Digest.String()); err != nil {
-		t.Fatal(err)
-	}
+func Test_referenceGraphTarget_Mount(t *testing.T) {
+	target := graphTarget{GraphTarget: &remote.Repository{}}
+	_ = target.Mount(context.Background(), ocispec.Descriptor{}, "", nil)
 }

cmd/oras/root/cp.go

@@ -29,6 +29,7 @@ import (
 	"oras.land/oras-go/v2"
 	"oras.land/oras-go/v2/content"
 	"oras.land/oras-go/v2/registry"
+	"oras.land/oras-go/v2/registry/remote"
 	"oras.land/oras-go/v2/registry/remote/auth"
 	"oras.land/oras/cmd/oras/internal/argument"
 	"oras.land/oras/cmd/oras/internal/display"
@@ -162,8 +163,15 @@ func doCopy(ctx context.Context, src oras.ReadOnlyGraphTarget, dst oras.GraphTar
 		promptCopying = "Copying"
 		promptCopied  = "Copied "
 		promptSkipped = "Skipped"
+		promptMounted = "Mounted"
 	)
-
+	srcRepo, srcIsRemote := src.(*remote.Repository)
+	dstRepo, dstIsRemote := dst.(*remote.Repository)
+	if srcIsRemote && dstIsRemote && srcRepo.Reference.Registry == dstRepo.Reference.Registry {
+		extendedCopyOptions.MountFrom = func(ctx context.Context, desc ocispec.Descriptor) ([]string, error) {
+			return []string{srcRepo.Reference.Repository}, nil
+		}
+	}
 	if opts.TTY == nil {
 		// none TTY output
 		extendedCopyOptions.OnCopySkipped = func(ctx context.Context, desc ocispec.Descriptor) error {
@@ -180,6 +188,10 @@ func doCopy(ctx context.Context, src oras.ReadOnlyGraphTarget, dst oras.GraphTar
 			}
 			return display.PrintStatus(desc, promptCopied, opts.Verbose)
 		}
+		extendedCopyOptions.OnMounted = func(ctx context.Context, desc ocispec.Descriptor) error {
+			committed.Store(desc.Digest.String(), desc.Annotations[ocispec.AnnotationTitle])
+			return display.PrintStatus(desc, promptMounted, opts.Verbose)
+		}
 	} else {
 		// TTY output
 		tracked, err := track.NewTarget(dst, promptCopying, promptCopied, opts.TTY)
@@ -198,6 +210,10 @@ func doCopy(ctx context.Context, src oras.ReadOnlyGraphTarget, dst oras.GraphTar
 				return tracked.Prompt(desc, promptSkipped)
 			})
 		}
+		extendedCopyOptions.OnMounted = func(ctx context.Context, desc ocispec.Descriptor) error {
+			committed.Store(desc.Digest.String(), desc.Annotations[ocispec.AnnotationTitle])
+			return tracked.Prompt(desc, promptMounted)
+		}
 	}
 
 	var desc ocispec.Descriptor

cmd/oras/root/cp_test.go

@@ -1,3 +1,5 @@
+//go:build darwin || freebsd || linux || netbsd || openbsd || solaris
+
 /*
 Copyright The ORAS Authors.
 Licensed under the Apache License, Version 2.0 (the "License");
@@ -19,37 +21,99 @@ import (
 	"bytes"
 	"context"
 	"fmt"
+	"net/http"
+	"net/http/httptest"
+	"net/url"
 	"os"
 	"testing"
 
 	"github.com/opencontainers/go-digest"
 	ocispec "github.com/opencontainers/image-spec/specs-go/v1"
 	"oras.land/oras-go/v2/content/memory"
+	"oras.land/oras-go/v2/registry/remote"
 	"oras.land/oras/cmd/oras/internal/display/console/testutils"
 )
 
 var (
-	src  *memory.Store
-	desc ocispec.Descriptor
+	memStore        *memory.Store
+	memDesc         ocispec.Descriptor
+	manifestConent  = []byte(`{"schemaVersion":2,"mediaType":"application/vnd.oci.image.manifest.v1+json","artifactType":"application/vnd.unknown.artifact.v1","config":{"mediaType":"application/vnd.oci.empty.v1+json","digest":"sha256:44136fa355b3678a1146ad16f7e8649e94fb4fc21fe77e8310c060f61caaff8a","size":2,"data":"e30="},"layers":[{"mediaType":"application/vnd.oci.empty.v1+json","digest":"sha256:44136fa355b3678a1146ad16f7e8649e94fb4fc21fe77e8310c060f61caaff8a","size":2,"data":"e30="}]}`)
+	manifestDigest  = "sha256:1bb053792feb8d8d590001c212f2defad9277e091d2aa868cde2879ff41abb1b"
+	configContent   = []byte("{}")
+	configDigest    = "sha256:44136fa355b3678a1146ad16f7e8649e94fb4fc21fe77e8310c060f61caaff8a"
+	configMediaType = "application/vnd.oci.empty.v1+json"
+	host            string
+	repoFrom        = "from"
+	repoTo          = "to"
 )
 
 func TestMain(m *testing.M) {
-	src = memory.New()
+	// memory store for testing
+	memStore = memory.New()
 	content := []byte("test")
 	r := bytes.NewReader(content)
-	desc = ocispec.Descriptor{
+	memDesc = ocispec.Descriptor{
 		MediaType: "application/octet-stream",
 		Digest:    digest.FromBytes(content),
 		Size:      int64(len(content)),
 	}
-	if err := src.Push(context.Background(), desc, r); err != nil {
+	if err := memStore.Push(context.Background(), memDesc, r); err != nil {
 		fmt.Println("Setup failed:", err)
 		os.Exit(1)
 	}
-	if err := src.Tag(context.Background(), desc, desc.Digest.String()); err != nil {
+	if err := memStore.Tag(context.Background(), memDesc, memDesc.Digest.String()); err != nil {
 		fmt.Println("Setup failed:", err)
 		os.Exit(1)
 	}
+
+	// test server
+	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		switch {
+		case r.URL.Path == fmt.Sprintf("/v2/%s/manifests/%s", repoFrom, manifestDigest) &&
+			r.Method == http.MethodHead:
+			w.Header().Set("Content-Type", ocispec.MediaTypeImageManifest)
+			w.Header().Set("Content-Length", fmt.Sprint(len(manifestConent)))
+			w.WriteHeader(http.StatusOK)
+		case r.URL.Path == fmt.Sprintf("/v2/%s/manifests/%s", repoFrom, manifestDigest) &&
+			r.Method == http.MethodGet:
+			w.Header().Set("Content-Type", ocispec.MediaTypeImageManifest)
+			w.Header().Set("Content-Length", fmt.Sprint(len(manifestConent)))
+			_, _ = w.Write(manifestConent)
+			w.WriteHeader(http.StatusOK)
+		case r.URL.Path == fmt.Sprintf("/v2/%s/blobs/%s", repoFrom, configDigest) &&
+			r.Method == http.MethodGet:
+			w.Header().Set("Content-Type", "application/octet-stream")
+			w.Header().Set("Content-Length", fmt.Sprint(len(configContent)))
+			_, _ = w.Write(configContent)
+			w.WriteHeader(http.StatusOK)
+		case r.URL.Path == fmt.Sprintf("/v2/%s/manifests/%s", repoTo, manifestDigest) &&
+			r.Method == http.MethodHead:
+			w.WriteHeader(http.StatusNotFound)
+		case r.URL.Path == fmt.Sprintf("/v2/%s/blobs/%s", repoTo, configDigest) &&
+			r.Method == http.MethodHead:
+			w.WriteHeader(http.StatusNotFound)
+		case r.URL.Path == fmt.Sprintf("/v2/%s/blobs/uploads/", repoTo) &&
+			r.URL.Query().Get("mount") == configDigest &&
+			r.URL.Query().Get("from") == repoFrom &&
+			r.Method == http.MethodPost:
+			w.Header().Set("Location", fmt.Sprintf("/v2/%s/blobs/%s", repoTo, configDigest))
+			w.WriteHeader(http.StatusCreated)
+		case r.URL.Path == fmt.Sprintf("/v2/%s/manifests/%s", repoTo, manifestDigest) &&
+			r.Method == http.MethodPut:
+			w.WriteHeader(http.StatusCreated)
+		case r.URL.Path == fmt.Sprintf("/v2/%s/manifests/%s", repoTo, manifestDigest) &&
+			r.Method == http.MethodGet:
+			w.Header().Set("Content-Type", ocispec.MediaTypeImageManifest)
+			w.Header().Set("Content-Length", fmt.Sprint(len(manifestConent)))
+			_, _ = w.Write(manifestConent)
+			w.WriteHeader(http.StatusOK)
+		default:
+			w.WriteHeader(http.StatusNotAcceptable)
+		}
+	}))
+	defer ts.Close()
+	uri, _ := url.Parse(ts.URL)
+	host = "localhost:" + uri.Port()
 	m.Run()
 }
 
@@ -63,15 +127,70 @@ func Test_doCopy(t *testing.T) {
 	var opts copyOptions
 	opts.TTY = slave
 	opts.Verbose = true
-	opts.From.Reference = desc.Digest.String()
+	opts.From.Reference = memDesc.Digest.String()
 	dst := memory.New()
 	// test
-	_, err = doCopy(context.Background(), src, dst, &opts)
+	_, err = doCopy(context.Background(), memStore, dst, &opts)
+	if err != nil {
+		t.Fatal(err)
+	}
+	// validate
+	if err = testutils.MatchPty(pty, slave, "Copied", memDesc.MediaType, "100.00%", memDesc.Digest.String()); err != nil {
+		t.Fatal(err)
+	}
+}
+
+func Test_doCopy_skipped(t *testing.T) {
+	// prepare
+	pty, slave, err := testutils.NewPty()
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer slave.Close()
+	var opts copyOptions
+	opts.TTY = slave
+	opts.Verbose = true
+	opts.From.Reference = memDesc.Digest.String()
+	// test
+	_, err = doCopy(context.Background(), memStore, memStore, &opts)
+	if err != nil {
+		t.Fatal(err)
+	}
+	// validate
+	if err = testutils.MatchPty(pty, slave, "Exists", memDesc.MediaType, "100.00%", memDesc.Digest.String()); err != nil {
+		t.Fatal(err)
+	}
+}
+
+func Test_doCopy_mounted(t *testing.T) {
+	// prepare
+	pty, slave, err := testutils.NewPty()
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer slave.Close()
+	var opts copyOptions
+	opts.TTY = slave
+	opts.Verbose = true
+	opts.From.Reference = manifestDigest
+	// mocked repositories
+	from, err := remote.NewRepository(fmt.Sprintf("%s/%s", host, repoFrom))
+	if err != nil {
+		t.Fatal(err)
+	}
+	from.PlainHTTP = true
+	to, err := remote.NewRepository(fmt.Sprintf("%s/%s", host, repoTo))
+	if err != nil {
+		t.Fatal(err)
+	}
+	to.PlainHTTP = true
+	// test
+	_, err = doCopy(context.Background(), from, to, &opts)
 	if err != nil {
 		t.Fatal(err)
 	}
 	// validate
-	if err = testutils.MatchPty(pty, slave, "Copied", desc.MediaType, "100.00%", desc.Digest.String()); err != nil {
+	if err = testutils.MatchPty(pty, slave, "Mounted", configMediaType, "100.00%", configDigest); err != nil {
 		t.Fatal(err)
 	}
 }

test/e2e/internal/utils/match/status.go

@@ -76,6 +76,7 @@ func newStateMachine(cmd string) *stateMachine {
 		sm.addPath("Copying", "Copied")
 		sm.addPath("Skipped")
 		sm.addPath("Exists")
+		sm.addPath("Mounted")
 	default:
 		ginkgo.Fail("Unrecognized cmd name " + cmd)
 	}

test/e2e/suite/command/cp.go

@@ -349,6 +349,15 @@ var _ = Describe("1.1 registry users:", func() {
 
 var _ = Describe("OCI spec 1.0 registry users:", func() {
 	When("running `cp`", func() {
+		It("should copy an image artifact with mounting", func() {
+			repo := cpTestRepo("1.0-mount")
+			src := RegistryRef(FallbackHost, ArtifactRepo, foobar.Tag)
+			dst := RegistryRef(FallbackHost, repo, "")
+			out := ORAS("cp", src, dst, "-v").Exec()
+			Expect(out).Should(gbytes.Say("Mounted fcde2b2edba5 bar"))
+			CompareRef(src, RegistryRef(FallbackHost, repo, foobar.Digest))
+		})
+
 		It("should copy an image artifact and its referrers from a registry to a fallback registry", func() {
 			repo := cpTestRepo("to-fallback")
 			stateKeys := append(append(foobar.ImageLayerStateKeys, foobar.ManifestStateKey, foobar.ImageReferrerConfigStateKeys[0]), foobar.ImageReferrersStateKeys...)