[Buildbot-devel] Buildbot unable to kill processes on windows slaves

[Jean-Paul Calderone]

On Tue, 28 Jul 2009 19:55:21 +0200, Marcus Lindblom <macke at yar.nu> wrote:
>Jonathan Rogers wrote:
>> Hi,
>>
>> We are having trouble with buildbot being unable to kill off processes
>> on a windows slave.
>>
>> The slave is running on windows vista in a command shell (not as a service).
>>
>> The error we get is "buildbot.slave.commands.TimeoutError: SIGKILL
>> failed to kill process". It seems to occur any time buildbot tries to
>> kill a process (be it via the "Stop Build" button or timing out).
>>
>> The annoying thing is that it requires someone to manually kill off the
>> process before another build can run because the next build is unable to
>> delete the directory due to the executable being locked.
>>
>> Any ideas on how to solve this issue would be appreciated.
>
>There is a ticket in Twisted's Trac for this. That contains a patch that
>helps with killing off spawned subprocesses.
>
>Why it hasn't been folded into the core after a few years, I don't know.
>

The currently active Twisted contributors are somewhat short on Windows
expertise (and, to be honest, interest).  The ticket:

  http://twistedmatrix.com/trac/ticket/2726

Has grown to include a mass of subtlety and complexity.  If I had four or
five days to spend on it, I think I could probably sort it out and come up
with a solution which was suitable to be included in trunk.  Alas, I don't.

It's great that the patch on the ticket solves the issue for the buildbot
users who have tried it out.  The change needs to be suitable for *all*
Twisted users, though.  A few other details need to be worked out as well,
like unit tests (the proposed patch includes none), error handling (the
patch ignores the possibility that the parent might be in a job already,
and that there are certain permissions required to split off of an existing
job before a new one can be created).  Much of this is mentioned in comments
on the ticket, but so far no one has stepped up to address the problems.

Anyone game to help out?  I'm happy to do shepherd this issue through the
Twisted development process, but I need someone with the Windows chops to
actually write some code.

Jean-Paul