- Make sure we log when an exception occurs in the squashing code

- Have queue file always try to return any remaining data in the buffer
- Remove the raise of the exception when we get an empty tar file

endpoints/verbs.py

@@ -49,6 +49,7 @@ def _write_synthetic_image_to_storage(linked_storage_uuid, linked_locations, que
   store = Storage(app)
 
   def handle_exception(ex):
+    logger.debug('Exception when building squashed image %s: %s', linked_storage_uuid, ex)
     model.delete_derived_storage_by_uuid(linked_storage_uuid)
 
   queue_file.add_exception_handler(handle_exception)

util/queuefile.py

@@ -20,7 +20,9 @@ class QueueFile(object):
 
   def read(self, size=8192):
     if self._closed or self._done:
-      return None
+      buf = self._buffer[0:size]
+      self._buffer = self._buffer[size:]
+      return buf
 
     while len(self._buffer) < size:
       result = self._queue.get(block=True)

util/tarlayerformat.py

@@ -13,7 +13,6 @@ class TarLayerFormat(object):
       try:
         tar_file = tarfile.open(mode='r|*', fileobj=current_tar)
       except tarfile.ReadError as re:
-        raise re
         continue
 
       # For each of the tar entries, yield them IF and ONLY IF we have not