Merge pull request #1294 from moio/allow-decompression

Add support for decompressing while copying to dir://

directory/directory_dest.go

@@ -21,13 +21,26 @@ const version = "Directory Transport Version: 1.1\n"
 var ErrNotContainerImageDir = errors.New("not a containers image directory, don't want to overwrite important data")
 
 type dirImageDestination struct {
-	ref      dirReference
-	compress bool
+	ref                     dirReference
+	desiredLayerCompression types.LayerCompression
 }
 
 // newImageDestination returns an ImageDestination for writing to a directory.
-func newImageDestination(ref dirReference, compress bool) (types.ImageDestination, error) {
-	d := &dirImageDestination{ref: ref, compress: compress}
+func newImageDestination(sys *types.SystemContext, ref dirReference) (types.ImageDestination, error) {
+	desiredLayerCompression := types.PreserveOriginal
+	if sys != nil {
+		if sys.DirForceCompress {
+			desiredLayerCompression = types.Compress
+
+			if sys.DirForceDecompress {
+				return nil, errors.Errorf("Cannot compress and decompress at the same time")
+			}
+		}
+		if sys.DirForceDecompress {
+			desiredLayerCompression = types.Decompress
+		}
+	}
+	d := &dirImageDestination{ref: ref, desiredLayerCompression: desiredLayerCompression}
 
 	// If directory exists check if it is empty
 	// if not empty, check whether the contents match that of a container image directory and overwrite the contents
@@ -101,10 +114,7 @@ func (d *dirImageDestination) SupportsSignatures(ctx context.Context) error {
 }
 
 func (d *dirImageDestination) DesiredLayerCompression() types.LayerCompression {
-	if d.compress {
-		return types.Compress
-	}
-	return types.PreserveOriginal
+	return d.desiredLayerCompression
 }
 
 // AcceptsForeignLayerURLs returns false iff foreign layers in manifest should be actually

directory/directory_transport.go

@@ -153,11 +153,7 @@ func (ref dirReference) NewImageSource(ctx context.Context, sys *types.SystemCon
 // NewImageDestination returns a types.ImageDestination for this reference.
 // The caller must call .Close() on the returned ImageDestination.
 func (ref dirReference) NewImageDestination(ctx context.Context, sys *types.SystemContext) (types.ImageDestination, error) {
-	compress := false
-	if sys != nil {
-		compress = sys.DirForceCompress
-	}
-	return newImageDestination(ref, compress)
+	return newImageDestination(sys, ref)
 }
 
 // DeleteImage deletes the named image from the registry, if supported.

types/types.go

@@ -636,6 +636,8 @@ type SystemContext struct {
 	// === dir.Transport overrides ===
 	// DirForceCompress compresses the image layers if set to true
 	DirForceCompress bool
+	// DirForceDecompress decompresses the image layers if set to true
+	DirForceDecompress bool
 
 	// CompressionFormat is the format to use for the compression of the blobs
 	CompressionFormat *compression.Algorithm