[THRIFT-637] Bug in TNonblockingServer.py for services with both oneway and regular requests

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.1, 0.2
• Fix Version/s: 0.1
• Component/s: Python - Library

Environment

All hardware/os combos, Python server

• Patch Info: Patch Available
• Assignee: Todd Lipcon
• Reporter: Arvind Sundararajan
• Created: 27/Nov/09 18:43
• Updated: 01/Nov/11 02:51
• Resolved: 03/Dec/09 01:20

Description

If you implement a service with TNonblockingServer.py and have both oneway and regular methods in your interface, the first regular request after a oneway request will fail with the error:

[TNonblockingServer.py :113 ] - 2009-11-26 13:58:01,829 - ERROR - can't read frame size from socket

This is because self.message is not cleaned up when there is no reply.

The implementation seems to start constructing a message in response
to a oneway request and then gives up once it realizes it is a oneway
request

def ready(self, all_ok, message):

....
self.message = struct.pack('!i', len(message)) + message
if len(message) == 0:

1. it was a oneway request, do not write answer
   self.status = WAIT_LEN

Then for the next regular message len(self.message) == 4 and self._read_len is very defensive about
reading only the exact right amount of data from the socket.

My patch is simple and seems to fix the problem:

> svn diff
Index: lib/py/src/server/TNonblockingServer.py
===================================================================
— lib/py/src/server/TNonblockingServer.py (revision 884669)
+++ lib/py/src/server/TNonblockingServer.py (working copy)
@@ -182,6 +182,7 @@
if len(message) == 0:

1. it was a oneway request, do not write answer
   self.status = WAIT_LEN
   + self.message = ''
   else:
   self.status = SEND_ANSWER
   self.wake_up()