exports: require caller to request frontend-based naming, by passing name of `%s`.

Signed-off-by: Ian Campbell <ijc@docker.com>

client/client_test.go

@@ -46,7 +46,7 @@ func TestClientIntegration(t *testing.T) {
 		testUser,
 		testOCIExporter,
 		testWhiteoutParentDir,
-		testFrontendImageNameTemplating,
+		testFrontendImageNaming,
 		testDuplicateWhiteouts,
 		testSchema1Image,
 		testMountWithNoSource,
@@ -114,7 +114,7 @@ func testNetworkMode(t *testing.T, sb integration.Sandbox) {
 	require.Contains(t, err.Error(), "network.host is not allowed")
 }
 
-func testFrontendImageNameTemplating(t *testing.T, sb integration.Sandbox) {
+func testFrontendImageNaming(t *testing.T, sb integration.Sandbox) {
 	requiresLinux(t)
 	t.Parallel()
 	c, err := New(context.TODO(), sb.Address())
@@ -224,7 +224,10 @@ func testFrontendImageNameTemplating(t *testing.T, sb integration.Sandbox) {
 			if winner == "ctrl" {
 				feName = "loser:latest"
 				so.ExporterAttrs["name"] = imageName
+			} else {
+				so.ExporterAttrs["name"] = "%s"
 			}
+
 			frontend := func(ctx context.Context, c gateway.Client) (*gateway.Result, error) {
 				res := gateway.NewResult()
 				res.AddMeta("image.name", []byte(feName))

exporter/containerimage/export.go

@@ -115,7 +115,7 @@ func (e *imageExporterInstance) Export(ctx context.Context, src exporter.Source)
 		e.opt.ImageWriter.ContentStore().Delete(context.TODO(), desc.Digest)
 	}()
 
-	if n, ok := src.Metadata["image.name"]; e.targetName == "" && ok {
+	if n, ok := src.Metadata["image.name"]; e.targetName == "%s" && ok {
 		e.targetName = string(n)
 	}
 

exporter/oci/export.go

@@ -72,9 +72,12 @@ func (e *imageExporter) Resolve(ctx context.Context, opt map[string]string) (exp
 	for k, v := range opt {
 		switch k {
 		case keyImageName:
-			i.name, err = normalize(v)
-			if err != nil {
-				return nil, err
+			i.name = v
+			if i.name != "%s" {
+				i.name, err = normalize(i.name)
+				if err != nil {
+					return nil, err
+				}
 			}
 		case ociTypes:
 			ot = new(bool)
@@ -138,7 +141,7 @@ func (e *imageExporterInstance) Export(ctx context.Context, src exporter.Source)
 	}
 	desc.Annotations[ocispec.AnnotationCreated] = time.Now().UTC().Format(time.RFC3339)
 
-	if n, ok := src.Metadata["image.name"]; e.name == "" && ok {
+	if n, ok := src.Metadata["image.name"]; e.name == "%s" && ok {
 		if e.name, err = normalize(string(n)); err != nil {
 			return nil, err
 		}