perl script as a running process

drfrog has asked for the wisdom of the Perl Monks concerning the following question:

hey

what im trying to do is build a perl script using Schedule::Cron and i want to run it like
>perl foo.pl &

i want to use $SIG{} events to trap if this script bails for some reason
here is the relevant piece of code taken from perlipc perlman:perlipc

 sub catch_zap {
        my $signame = shift;
        die "Somebody sent me a SIG$signame";
    }
    $SIG{INT} = \&catch_zap;
[download]

ive been trying to test with various variations of
'kill -9 PID'

what would you monks suggest needs to be trapped so i would know when my script fails?

Comment on perl script as a running process Download Code

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Re: perl script as a running process by fglock (Vicar) on Jun 30, 2003 at 19:15 UTC
Some time ago I read that 'kill -9 PID' is not trappable. It kills the process before it can properly die. update: from perlipc: Some signals can be neither trapped nor ignored, such as the KILL and STOP (but not the TSTP) signals.	[reply]
Re: Re: perl script as a running process by isotope (Deacon) on Jun 30, 2003 at 19:36 UTC
Correct. Signal 9 is SIGKILL, which is not actually sent to the process; it tells the kernel to terminate it without remorse. If you're trying to catch INT, send INT (kill -2) or for TERM, -15. --isotope	[reply]
Persistent Perl by barbie (Deacon) on Jul 01, 2003 at 11:25 UTC
Nothing to do with the signal question, but you might be interested in PPerl for your running process. Seems to be gaining in popularity. Rather like mod_perl for stand alone scripts. -- Barbie \| Birmingham Perl Mongers \| http://birmingham.pm.org/	[reply]
Re: perl script as a running process by nimdokk (Vicar) on Jun 30, 2003 at 19:08 UTC
One of the things that I have is a step to capture the actual error messages that might go to STDERR. I try to capture all the output of a program into a logfile. I use an END block to determine whether the program exits cleanly or if its generated an error. Different exits determine differnt behaviors. For instance, when the program dies, it sends out an alert to a pager and makes a copy of the log so that I (or someone else) can look at the errored log and see what blew up (in case the actual log gets overwritten before we can get dialed in). You might look at using $SIG {__DIE__}. Just my own 2 cents though :-) "Ex libris un peut de tout"	[reply]
Re: perl script as a running process by drfrog (Deacon) on Jun 30, 2003 at 19:40 UTC
so if i catch -2 and -15 I should be fine?	[reply]
Re: Re: perl script as a running process by nimdokk (Vicar) on Jun 30, 2003 at 20:14 UTC
You should be OK as long as you don't try to catch -22 ;-) "Ex libris un peut de tout"	[reply]