client: Client.ImageSave: close reader on context cancellation

Use a cancelReadCloser to automatically close the reader when the context
is cancelled. Consumers are still recommended to manually close the reader,
but the cancelReadCloser makes the Close idempotent.

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

integration/build/build_userns_linux_test.go

@@ -75,7 +75,7 @@ func TestBuildUserNamespaceValidateCapabilitiesAreV2(t *testing.T) {
 
 	reader, err := clientUserRemap.ImageSave(ctx, []string{imageTag})
 	assert.NilError(t, err, "failed to download capabilities image")
-	defer reader.Close()
+	defer func() { _ = reader.Close() }()
 
 	tar, err := os.Create(filepath.Join(tmpDir, "image.tar"))
 	assert.NilError(t, err, "failed to create image tar file")

integration/daemon/migration_test.go

@@ -130,8 +130,8 @@ func TestMigrateSaveLoad(t *testing.T) {
 	rdr, err := apiClient.ImageSave(ctx, []string{"busybox:latest"})
 	assert.NilError(t, err)
 	buf := bytes.NewBuffer(nil)
-	io.Copy(buf, rdr)
-	rdr.Close()
+	_, _ = io.Copy(buf, rdr)
+	defer func() { _ = rdr.Close() }()
 
 	// Delete all images
 	list, err := apiClient.ImageList(ctx, client.ImageListOptions{})

integration/image/save_test.go

@@ -44,7 +44,7 @@ func tarIndexFS(t *testing.T, rdr io.Reader) fs.FS {
 	assert.NilError(t, err)
 
 	// Do not close at the end of this function otherwise the indexer won't work
-	t.Cleanup(func() { f.Close() })
+	t.Cleanup(func() { _ = f.Close() })
 
 	_, err = io.Copy(f, rdr)
 	assert.NilError(t, err)
@@ -64,6 +64,7 @@ func TestSaveCheckTimes(t *testing.T) {
 
 	rdr, err := apiClient.ImageSave(ctx, []string{repoName})
 	assert.NilError(t, err)
+	defer func() { _ = rdr.Close() }()
 
 	created, err := time.Parse(time.RFC3339, img.Created)
 	assert.NilError(t, err)
@@ -135,7 +136,7 @@ func TestSaveOCI(t *testing.T) {
 
 			rdr, err := apiClient.ImageSave(ctx, []string{tc.image})
 			assert.NilError(t, err)
-			defer rdr.Close()
+			defer func() { _ = rdr.Close() }()
 
 			tarfs := tarIndexFS(t, rdr)
 
@@ -171,7 +172,7 @@ func TestSaveOCI(t *testing.T) {
 					assert.NilError(t, err)
 
 					layerDigest, err := testutil.UncompressedTarDigest(f)
-					f.Close()
+					_ = f.Close()
 
 					assert.NilError(t, err)
 
@@ -426,7 +427,7 @@ func TestSaveRepoWithMultipleImages(t *testing.T) {
 
 	rdr, err := apiClient.ImageSave(ctx, []string{repoName, "busybox:latest"})
 	assert.NilError(t, err)
-	defer rdr.Close()
+	defer func() { _ = rdr.Close() }()
 
 	tarfs := tarIndexFS(t, rdr)
 
@@ -483,7 +484,7 @@ RUN touch /opt/a/b/c && chown user:user /opt/a/b/c`
 
 	rdr, err := apiClient.ImageSave(ctx, []string{imgID})
 	assert.NilError(t, err)
-	defer rdr.Close()
+	defer func() { _ = rdr.Close() }()
 
 	tarfs := tarIndexFS(t, rdr)
 

integration/plugin/authz/authz_plugin_test.go

@@ -425,17 +425,17 @@ func TestAuthzPluginEnsureContainerCopyToFrom(t *testing.T) {
 }
 
 func imageSave(ctx context.Context, apiClient client.APIClient, path, imgRef string) error {
-	responseReader, err := apiClient.ImageSave(ctx, []string{imgRef})
+	resp, err := apiClient.ImageSave(ctx, []string{imgRef})
 	if err != nil {
 		return err
 	}
-	defer responseReader.Close()
+	defer func() { _ = resp.Close() }()
 	file, err := os.Create(path)
 	if err != nil {
 		return err
 	}
-	defer file.Close()
-	_, err = io.Copy(file, responseReader)
+	_, err = io.Copy(file, resp)
+	_ = file.Close()
 	return err
 }