Re: At most 1 running copy

[Doug Stewart <dstewart@xxxxxxxxxxxx>]

Ed Wilts wrote:

> I'm looking for a fool-proof way to ensure that at most 1 copy per user
> is running of a single Perl script.  This code is horribly ugly and
> needs to be scheduled frequently via cron but occasionally may run for a
> very long time.  I'd like to ensure that if a copy is already running,
> another one doesn't start up.  I need to do this with very minimal
> changes to the running code (as I said, it's ugly and already does a
> very poor job of error handling).
>
> Any ideas would be greatly appreciated.  The developer had this coded in
> there, but it's not always working correctly:
>
> my $My_Name = getlogin || (getpwuid($<))[0];
> my $ProgName = 'ftphandler.pl';  # update if program name changes
> # check to see if user is already running program
> my $Running=`ps -ef|grep $My_Name | grep perl | grep -c $ProgName`;
> chop($Running);
> if ($Running > 2) {
> #print "already running.\n";
> unlink("$Tmplog");
> exit;
> }
>
> It's not my code, but I get to be the lucky guy to fix it and I'm a
> crappy Perl coder...
>
> Thanks,
>        .../Ed
>  
It might be a better idea to simply write out a "lockfile" and check for 
its presence before running.

--
------------
Doug Stewart
Systems Administrator/Web Applications Developer
Lockheed Martin Advanced Technology Labs 
dstewart@xxxxxxxxxxxx