Debugging SocketServer.ThreadingTCPServer

[Stuart D. Gathman]

On Tue, 16 Jan 2007 09:11:38 -0500, Jean-Paul Calderone wrote:

> On Tue, 16 Jan 2007 00:23:35 -0500, "Stuart D. Gathman"
> <stuart at bmsi.com> wrote:
>>I have a ThreadingTCPServer application (pygossip, part of
>>http://sourceforge.net/projects/pymilter).  It mostly runs well, but
>>occasionally goes into a loop.  How can I get a stack trace of running
>>threads to figure out where the loop is?  Is there some equivalent of
>>sending SIGQUIT to Java to get a thread dump?  If needed, I can import
>>pdb and set options at startup, but there needs to be some external way
>>of triggering the dump since I can't reproduce it at will.
> 
> Grab the gdbinit out of Python SVN Misc/ directory.  Apply this patch:
> 
>   http://jcalderone.livejournal.com/28224.html
> 
> Attach to the process using gdb.  Make sure you have debugging symbols
> in your build of Python.  Run 'thread apply all pystack'.

Did this.  gdb displays main thread fine (waiting on accept(), duh).  But
gdb goes into a loop displaying the first worker thread.  There are no
extension modules other than the batteries included ones. In this
application, I believe, only _socket.  (I.e. a pure python server.)

I will try for a C stack trace next time it loops.

Also, the looping server needs kill -9.  SIGTERM and SIGINT won't stop it.
And after it dies with SIGKILL, the port is still in use for 5 minutes or
so (and the server cannot be restarted).

This is really making me appreciate Java.

-- 
	      Stuart D. Gathman <stuart at bmsi.com>
Business Management Systems Inc.  Phone: 703 591-0911 Fax: 703 591-6154
"Confutatis maledictis, flamis acribus addictis" - background song for
a Microsoft sponsored "Where do you want to go from here?" commercial.