From: ara.t.howard@...
Date: 2006-05-02T03:55:45+09:00
Subject: Re: Generate unique filenames

On Tue, 2 May 2006, Kirk Haines wrote:

> On Monday 01 May 2006 12:00 pm, ara.t.howard@noaa.gov wrote:
>
>> it seems like that, but it does not.  File::EXCL is broken on many
>> filesystems and, worse, fails silently.  one needs to use a tmpnam
>> algorithm with hostname/pid/time/rand to minimize the chances of dup names
>> or use a form of locking which works on all filesystems.  afaik the only
>> portable atomic fs operation is 'link' and, ergo, the locking mechanism
>> must be built on top of this.  my lockfile class has an impl if your
>
> The link implementation in your lockfile lib won't work right on, at the very
> least Windows XP.
>
> I have a modified version of it in my IOWA dev tree that, if not told what
> style of locking to do, tests the matter when a lockfile is first created and
> attempts to guess at the appropriate flavor of lockfile.
>
> It is, currently, a less than wholly elegant integration with a somewhat
> simplified version of your lockfile.rb, but it works and passes its tests on
> WinXP as well as the couple different flavors of Linux I have tested on.

cool.  i've never even attempted this on any windowsy platform.  maybe we
should merge?  a good lockfile class is a must for any production system, as
anyone who's even come back from a  4 days weekend to find 4000 stacked and
hung crontab processes knows ;-)

cheers.

-a
-- 
be kind whenever possible... it is always possible.
- h.h. the 14th dali lama