Log stream_write_to_fp ioerrors

storage/cloud.py

@@ -175,6 +175,8 @@ class _CloudStorage(BaseStorageV2):
     # We are going to reuse this but be VERY careful to only read the number of bytes written to it
     buf = StringIO.StringIO()
 
+    chunk_sizes = []
+
     num_part = 1
     total_bytes_written = 0
     while size == filelike.READ_UNTIL_END or total_bytes_written < size:
@@ -190,6 +192,8 @@ class _CloudStorage(BaseStorageV2):
         if bytes_staged == 0:
           break
 
+        chunk_sizes.append(bytes_staged)
+
         buf.seek(0)
         mp.upload_part_from_file(buf, num_part, size=bytes_staged)
         total_bytes_written += bytes_staged
@@ -202,7 +206,11 @@ class _CloudStorage(BaseStorageV2):
 
     if total_bytes_written > 0:
       app.metric_queue.put('MultipartUploadSuccess', 1)
-      mp.complete_upload()
+      try:
+        mp.complete_upload()
+      except:
+        logger.error('complete_upload failed: chunk_sizes: %s', chunk_sizes)
+        raise
     return total_bytes_written
 
   def list_directory(self, path=None):