On 27 Dec 2000, at 10:11, Mark Murray wrote:
> > Any ideas on how to do this? Any suggestions on the process?
>
> Simple lock (like flock(3)) in the perl script. Lock some ${FILE},
> and if you can't get the lock, die. The file should contain the PID
> of the process that holds the lock, so that a cleanerd can kill
> stuck processes, or so that the lock can be blown away if needed.
>
> Works like a charm.
Mark and I have been msging offline and he's agreed to my posting the
results of our discussion:
> > > > Thanks Mark. But what part of the solution does flock solve?
> > >
> > > It prevents more than one perl script from running. You can then
> > > cron perl scripts to deal with the incoming, and not worry about
> > > them jumping on each other.
> >
> > Yes. That does make some things much easier. That's a very
> > simple solution.
> >
> > I was looking for a gold-plated solution where messages are
> > processed right away. But it sounds too complicated. I guess
> > setting up a cron job to run every minute is fine.
> >
> > The perl script looks like this:
> >
> > flock a file, if it fails, die.
>
> Write PID to flocked file.
>
> > Loop
> > Get oldest file in directory (file are named Y.m.d.h.m.s.PID)
> > process it
> > move file to archives
> > until no more files
>
> Truncate file
>
> > unlock the file
> >
> > The cleaner you mentioned: run it every 15 minutes, compare the
> > date/time on the lockfile, if more than 15 minutes old, grab the PID,
> > and kill the job, remove the lock.
>
> Correct.
Thanks Mark.
--
Dan Langille
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