[Twisted-Python] sigchld

[Jason Rennie]

Thanks for all the help.  We're going with addSystemEventTrigger for now,
but we'll keep twistd in mind for future work.

Jason

On Fri, Feb 11, 2011 at 1:51 PM, Glyph Lefkowitz <glyph at twistedmatrix.com>wrote:

>
> On Feb 11, 2011, at 11:55 AM, exarkun at twistedmatrix.com wrote:
>
> > On 03:59 pm, jrennie at gmail.com wrote:
> >> On Fri, Feb 11, 2011 at 10:01 AM, <exarkun at twistedmatrix.com> wrote:
> >>> On Python 2.5 and earlier you won't be able to get Twisted's SIGCHLD
> >>> handler using signal.getsignal.
> >>
> >> We're also moving to python 2.6 (the change is really Debian 5 to
> >> Debian 6).
> >> Should it would work in 2.6?
> >
> > I think so.
> >>
> >>> What sort of things do your signal handlers do?
> >>
> >> IIRC, the main thing is to shut down the web server (cherrypy) we're
> >> running
> >> in parallel with twisted.  We also have some disk-caching for stateful
> >> signals which needs to ensure the cache file is up-to-date.
> >
> > For shutdown-type things, reactor.addSystemEventTrigger(phase,
> > 'shutdown', f) might be better than getting into signal handlers (where
> > phase is 'before', 'during', or 'after').
>
>
> There's already a system event trigger already hooked up to the reactor:
> your main service's stopService call.  If your cherrypy webserver is wrapped
> up in an IService implementation in the service hierarchy constructed in
> your twistd plugin or tac file, you can just implement 'stopService' and not
> do any manual registration with event triggers.  This is really a better way
> to go in general, as it's easier for other API consumers to deal with such
> an object than using the global broadcasting mechanism in the reactor.
>
> If you do want to manually add your own system event trigger, in most
> interesting cases you'll need to use the 'before' phase.  During 'before',
> Deferreds returned by event triggers are respected (i.e. the reactor keeps
> running as long as they haven't fired).  If you schedule one for 'during' or
> 'after', the event trigger really needs to do all of its work and complete
> it immediately (i.e. before returning).
>
>
> _______________________________________________
> Twisted-Python mailing list
> Twisted-Python at twistedmatrix.com
> http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python
>



-- 
Jason Rennie
Research Scientist, ITA Software
617-714-2645
http://www.itasoftware.com/
-------------- next part --------------
An HTML attachment was scrubbed...
URL: </pipermail/twisted-python/attachments/20110215/c1ec80d0/attachment-0001.html>