Clarification on upstart-0.5 and dbus usage

[Matthias Urlichs]

Hi,

Scott James Remnant:
> On Thu, 2008-06-19 at 01:24 +0200, Matthias Urlichs wrote:
> 
> > Scott James Remnant:
> > > 	pid = instance.Get("pid")["main"]
> > > 
> > > 	# Muck around with pid as you see fit
> > > 	if os.path.isfile("/tmp/%d" % pid):
> > > 	    return
> > > 
> > > 	# Oh dear, it's broken
> > > 	instance.Restart()
> > 
> > Nice race condition there. :-P
> > 
> What's the race?

The Program starts but doesn't yet have the pidfile created,
for whatever reason.

You run the above code, killing and restarting the program
before it's ready.

Repeat.


The fix would obviously be to note that the program is in "starting"
instead of "started" state; of course, Upstart needs to notice / get
told about the transition from the former to the latter for that to
work, hence the complexity I mentioned.

But we've had this discussion before ...

-- 
Matthias Urlichs   |   {M:U} IT Design @ m-u-it.de   |  smurf at smurf.noris.de
Disclaimer: The quote was selected randomly. Really. | http://smurf.noris.de
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