Cron and perl script

[rthur]

Hello!

I'm having some issues running a perl script with cron. If I execute it directly everything works fine, but when cron does certain parts do not work... I've tried sending the output to dev/null, all paths are full paths yet I still can't get it to work.
Here is a working excerpt of the script. Under cron if the process "named" is not detected the command "service named restart" is not executed (or at least so I think)...

#!/usr/bin/perl

my @services = ( 'named' );

sub bindcheck {

foreach my $service (@services) {
	my $procstatus = `/bin/ps cax | /bin/grep $service`;

		if (!$procstatus) {
			$bind=20;
			$bindstatus="Down";

		} else {
			$bind=10;
			$bindstatus="Running";

		}
	}

}

&bindcheck;

if ( $bind == 20 ) {
		system("service named restart");
		&bindcheck;
	}

Thanks a lot for your precious help!

Arthur

[FishMonger]

The first step would be to add the strict and warnings pragmas and fix the problems they point out. Those 2 pragmas should be in every Perl script you write.

#!/usr/bin/perl

use strict;
use warnings;

Next, you need to add some debugging statements and send the output to a file. Make sure you open the file in a world writable directory. The debug statements should test that the script can both read and execute each of the system commands.

As written, I would not expect the "service named restart" command to work for the following 2 reasons. 1) It lacks the path to the command. 2) The service command is a privileged command, i.e., requires root privileges which the user account that cron runs under (which I think is "nobody") most likely doesn't have.

[FishMonger]

Here are some useful modules related to your task.

IPC::Run - system() and background procs w/ piping, redirs, ptys (Unix, Win32)
Unix::Process - Perl extension to get pid info from (/bin/ps).
Sudo - Perl extension for running a command line sudo

[rthur]

Thanks a lot for all your help!

I'm pretty new at this and wasn't sure as to how to write a statement that would be able to tell me if that command was executed successfully or not, but you were right, replacing "service named start" with "etc/init.d/named start" did the trick. (As for the permissions, I was under the impression that seeing as this command is executed under root's crontab that it would be run as root)

I'll start looking into writing debuging statements, I could picture those coming in handy at some point (like yesterday )

I don't really get the point of the "use strict" pragma however....

Thanks!

Arthur