Merge pull request #18252 from aaronlehmann/tarstream-readcloser

Make TarStream return an io.ReadCloser

daemon/commit.go

@@ -155,6 +155,7 @@ func (daemon *Daemon) exportContainerRw(container *Container) (archive.Archive,
 		return nil, err
 	}
 	return ioutils.NewReadCloserWrapper(archive, func() error {
+			archive.Close()
 			return daemon.layerStore.Unmount(container.ID)
 		}),
 		nil

distribution/push_v1.go

@@ -429,6 +429,7 @@ func (p *v1Pusher) pushImage(v1Image v1Image, ep string) (checksum string, err e
 	if err != nil {
 		return "", err
 	}
+	defer arch.Close()
 
 	// don't care if this fails; best effort
 	size, _ := l.Size()

distribution/push_v2.go

@@ -365,6 +365,7 @@ func (p *v2Pusher) pushV2Layer(bs distribution.BlobService, l layer.Layer) (dige
 	if err != nil {
 		return "", err
 	}
+	defer arch.Close()
 
 	// Send the layer
 	layerUpload, err := bs.Create(context.Background())

image/tarexport/save.go

@@ -287,6 +287,8 @@ func (s *saveSession) saveLayer(id layer.ChainID, legacyImg image.V1Image, creat
 	if err != nil {
 		return err
 	}
+	defer arch.Close()
+
 	if _, err := io.Copy(tarFile, arch); err != nil {
 		return err
 	}

layer/empty.go

@@ -4,6 +4,7 @@ import (
 	"archive/tar"
 	"bytes"
 	"io"
+	"io/ioutil"
 )
 
 // DigestSHA256EmptyTar is the canonical sha256 digest of empty tar file -
@@ -15,11 +16,11 @@ type emptyLayer struct{}
 // EmptyLayer is a layer that corresponds to empty tar.
 var EmptyLayer = &emptyLayer{}
 
-func (el *emptyLayer) TarStream() (io.Reader, error) {
+func (el *emptyLayer) TarStream() (io.ReadCloser, error) {
 	buf := new(bytes.Buffer)
 	tarWriter := tar.NewWriter(buf)
 	tarWriter.Close()
-	return buf, nil
+	return ioutil.NopCloser(buf), nil
 }
 
 func (el *emptyLayer) ChainID() ChainID {

layer/layer.go

@@ -67,7 +67,7 @@ func (diffID DiffID) String() string {
 type TarStreamer interface {
 	// TarStream returns a tar archive stream
 	// for the contents of a layer.
-	TarStream() (io.Reader, error)
+	TarStream() (io.ReadCloser, error)
 }
 
 // Layer represents a read only layer

layer/layer_store.go

@@ -581,7 +581,7 @@ func (ls *layerStore) Changes(name string) ([]archive.Change, error) {
 	return ls.driver.Changes(m.mountID, pid)
 }
 
-func (ls *layerStore) assembleTar(graphID string, metadata io.ReadCloser, size *int64) (io.Reader, error) {
+func (ls *layerStore) assembleTar(graphID string, metadata io.ReadCloser, size *int64) (io.ReadCloser, error) {
 	type diffPathDriver interface {
 		DiffPath(string) (string, func() error, error)
 	}

layer/layer_test.go

@@ -100,6 +100,7 @@ func createLayer(ls Store, parent ChainID, layerFunc layerInit) (Layer, error) {
 	if err != nil {
 		return nil, err
 	}
+	defer ts.Close()
 
 	layer, err := ls.Register(ts, parent)
 	if err != nil {
@@ -521,6 +522,7 @@ func assertLayerDiff(t *testing.T, expected []byte, layer Layer) {
 	if err != nil {
 		t.Fatal(err)
 	}
+	defer ts.Close()
 
 	actual, err := ioutil.ReadAll(ts)
 	if err != nil {

layer/mounted_layer.go

@@ -22,12 +22,12 @@ func (ml *mountedLayer) cacheParent() string {
 	return ""
 }
 
-func (ml *mountedLayer) TarStream() (io.Reader, error) {
+func (ml *mountedLayer) TarStream() (io.ReadCloser, error) {
 	archiver, err := ml.layerStore.driver.Diff(ml.mountID, ml.cacheParent())
 	if err != nil {
 		return nil, err
 	}
-	return autoClosingReader{archiver}, nil
+	return archiver, nil
 }
 
 func (ml *mountedLayer) Path() (string, error) {
@@ -50,15 +50,3 @@ func (ml *mountedLayer) Parent() Layer {
 func (ml *mountedLayer) Size() (int64, error) {
 	return ml.layerStore.driver.DiffSize(ml.mountID, ml.cacheParent())
 }
-
-type autoClosingReader struct {
-	source io.ReadCloser
-}
-
-func (r autoClosingReader) Read(p []byte) (n int, err error) {
-	n, err = r.source.Read(p)
-	if err != nil {
-		r.source.Close()
-	}
-	return
-}

layer/ro_layer.go

@@ -14,7 +14,7 @@ type roLayer struct {
 	references     map[Layer]struct{}
 }
 
-func (rl *roLayer) TarStream() (io.Reader, error) {
+func (rl *roLayer) TarStream() (io.ReadCloser, error) {
 	r, err := rl.layerStore.store.TarSplitReader(rl.chainID)
 	if err != nil {
 		return nil, err

migrate/v1/migratev1_test.go

@@ -360,7 +360,7 @@ type mockLayer struct {
 	parent  *mockLayer
 }
 
-func (l *mockLayer) TarStream() (io.Reader, error) {
+func (l *mockLayer) TarStream() (io.ReadCloser, error) {
 	return nil, nil
 }