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Date: Tue, 31 Mar 2015 17:58:09 +0200
From: Ervin =?utf-8?Q?Heged=C3=BCs?= <airween@gmail.com>
To: Matthew Ruffalo <mmr15@case.edu>
Cc: python-list@python.org
Subject: Re: Lockfile hanling
References: <20150331145012.GA4460@arxnet.hu> <551AC22E.40209@case.edu>
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Hi Matthew,

On Tue, Mar 31, 2015 at 11:50:06AM -0400, Matthew Ruffalo wrote:
> On 2015-03-31 10:50, Ervin Hegedüs wrote:
> > there is an app, written in Python, which stores few bytes of
> > datas in a single file. The application uses threads. Every
> > thread can modify the file, but only one at a time. I'm using a
> > lock file to prevent the multiple access.
> >
> > ...
> >
> > How can I prevent or avoid this issue? What's the correct way to
> > handle the lockfile in Python?
> 
> Hi Ervin-
> 
> If only one instance of the app is running at a given time, and you only
> need to ensure mutual exclusion between its threads, you should probably
> not use a lock *file* for this. I would strongly recommend that you use
> a threading.Lock as per
> https://docs.python.org/2.5/lib/module-threading.html instead of a lock
> file. This will also allow you to avoid a 0.2-second polling loop; a
> call to threading.Lock.acquire() will block until it is released by
> another thread.
> 
> MMR...

thanks, I hope in the next version I can try this :)


a.