Change back to using a docker load format

util/streamlayerformat.py

@@ -32,30 +32,30 @@ class StreamLayerMerger(object):
       chunk_size = 1024 * 1024 * 9
 
       for tar_info in tar_file:
-        result = self.process_tar_info(tar_info)
-        if not result:
+        if not self.check_tar_info(tar_info):
           continue
 
-        (tarinfo, filebuf) = result
+        # Yield the tar header.
+        yield tar_info.tobuf()
 
-        yield tarinfo.tobuf()
+        # Try to extract any file contents for the tar. If found, we yield them as well.
+        if tar_info.isreg():
+          file_stream = tar_file.extractfile(tar_info)
+          if file_stream is not None:
+            length = 0
+            while True:
+              current_block = file_stream.read(chunk_size)
+              if not len(current_block):
+                break
 
-        if filebuf:
-          length = 0
-          file_stream = tar_file.extractfile(tarinfo)
-          while True:
-            current_block = file_stream.read(chunk_size)
-            if not len(current_block):
-              break
+              yield current_block
+              length += len(current_block)
 
-            yield current_block
-            length += len(current_block)
+            file_stream.close()
 
-          file_stream.close()
-
-          # Files must be padding to 512 byte multiples.
-          if length % 512 != 0:
-            yield '\0' * (512 - (length % 512))
+            # Files must be padding to 512 byte multiples.
+            if length % 512 != 0:
+              yield '\0' * (512 - (length % 512))
 
       # Close the layer stream now that we're done with it.
       tar_file.close()
@@ -68,24 +68,24 @@ class StreamLayerMerger(object):
     yield '\0' * 512
 
 
-  def process_tar_info(self, tar_info):
+  def check_tar_info(self, tar_info):
     absolute = os.path.relpath(tar_info.name.decode('utf-8'), './')
 
     # Skip metadata.
     if is_aufs_metadata(absolute):
-      return None
+      return False
 
     # Add any prefix of deleted paths to the prefix list.
     deleted_prefix = get_deleted_prefix(absolute)
     if deleted_prefix is not None:
       self.encountered.append(deleted_prefix)
-      return None
+      return False
 
     # Check if this file has already been encountered somewhere. If so,
     # skip it.
     if unicode(absolute) in self.trie:
-      return None
+      return False
 
     # Otherwise, add the path to the encountered list and return it.
     self.encountered.append(absolute)
-    return (tar_info, tar_info.isfile() or tar_info.isdev())
+    return True