Fix bug in dockerloadformat and make sure we handle exceptions properly in the verb call

util/dockerloadformat.py

@@ -26,7 +26,6 @@ def build_docker_load_stream(namespace, repository, tag, synthetic_image_id,
 
 def _import_format_generator(namespace, repository, tag, synthetic_image_id,
                              layer_json, get_image_iterator, get_layer_iterator):
-
   # Docker import V1 Format (.tar):
   #  repositories - JSON file containing a repo -> tag -> image map
   #  {image ID folder}:
@@ -69,7 +68,7 @@ def _import_format_generator(namespace, repository, tag, synthetic_image_id,
     yielded_size += len(entry)
 
   # If the yielded size is more than the estimated size (which is unlikely but possible), then
-  # raise an exception since the tar header will be wrong.
+  # raise an exception since the tar header will be wrong.  
   if yielded_size > estimated_file_size:
     raise FileEstimationException()
 
@@ -114,6 +113,7 @@ def _tar_file_padding(length):
   if length % 512 != 0:
     return '\0' * (512 - (length % 512))
 
+  return ''
 
 def _tar_file_header(name, file_size):
   info = tarfile.TarInfo(name=name)

util/queuefile.py

@@ -12,6 +12,11 @@ class QueueFile(object):
     self._buffer = ''
     self._total_size = 0
     self._name = name
+    self.raised_exception = False
+    self._exception_handlers = []
+
+  def add_exception_handler(self, handler):
+    self._exception_handlers.append(handler)
 
   def read(self, size=8192):
     if self._closed or self._done:
@@ -25,7 +30,11 @@ class QueueFile(object):
 
       if isinstance(result, Exception):
         self._closed = True
-        raise result
+        self.raised_exception = True
+        for handler in self._exception_handlers:
+          handler(result)
+          
+        return
 
       self._buffer += result
       self._total_size += len(result)