Generic Daemon Use

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

Hello,

I'm trying to use the generic daemon from:
Generic Daemon CPAN

I'm starting with trying the example from the module. I cannot get the daemon to run. I get no error messages; just a message saying the daemon is starting. When I run the "check" subroutine it says that the config is fine and the daemon is not running. Here is the code I'm trying to get working. Does someone have a working example of this? Thanks!


#!/usr/bin/perl
use warnings;
use Daemon::Generic;

my $sleeptime = 1;

 newdaemon(
        progname        => 'ticktockd',
        pidfile         => '/var/run/ticktockd.pid',
        configfile      => '/etc/ticktockd.conf',
 );

 sub gd_preconfig
 {
        my ($self) = @_;
        open(CONFIG, "</etc/ticktockd.conf") or die;
        while(<CONFIG>) {
                $sleeptime = $1 if /^sleeptime\s+(\d+)/;
        }
        close(CONFIG);
        return ();
 }

 sub gd_run
 {
        while(1) {
                sleep($sleeptime);
                print scalar(localtime(time))."\n";
        }
 }
[download]

Comment on Generic Daemon Use Download Code

Replies are listed 'Best First'.
Re: Generic Daemon Use by andyford (Curate) on Feb 02, 2007 at 16:34 UTC
Do you have a "/etc/ticktockd.conf"? Could it be die-ing trying to read a non-existant file? Maybe change `open(CONFIG, "</etc/ticktockd.conf") or die;` [download] to `open(CONFIG, "</etc/ticktockd.conf") or die "Failure opening config fi +le: $!"` [download] non-Perl: Andy Ford	[reply] [d/l] [select]
Re^2: Generic Daemon Use by smist (Acolyte) on Feb 02, 2007 at 18:05 UTC
Thanks for the reply. I do have the conf file in /etc. I'm getting no error output when using $!.	[reply]
Re^3: Generic Daemon Use by andyford (Curate) on Feb 02, 2007 at 18:20 UTC
Here's another thought: run your Daemon in the foreground: `newdaemon( progname => 'ticktockd', pidfile => '/var/run/ticktockd.pid', configfile => '/etc/ticktockd.conf', foreground => 1, );` [download] If it's running in the background you may never see any output. non-Perl: Andy Ford	[reply] [d/l]
Re^4: Generic Daemon Use by smist (Acolyte) on Feb 02, 2007 at 18:41 UTC
Re^5: Generic Daemon Use by dirving (Friar) on Feb 03, 2007 at 02:53 UTC
Re^5: Generic Daemon Use by andyford (Curate) on Feb 02, 2007 at 18:54 UTC
Re^3: Generic Daemon Use by andyford (Curate) on Feb 02, 2007 at 18:14 UTC
Well then, I'd say it's probably time to start sprinkling print statements into your code. For instance you might do (untested) `sub gd_preconfig { my ($self) = @_; print "opening config file\n"; open(CONFIG, "</etc/ticktockd.conf") or die "Failure opening c +onfig file:$!"; while(<CONFIG>) { $sleeptime = $1 if /^sleeptime\s+(\d+)/; } close(CONFIG); print "done reading config, sleeptime is now $sleeptime\n"; return (); }` [download] Oh, and I just noticed that you need to add "use strict" to the top of your program! Very important! non-Perl: Andy Ford	[reply] [d/l]
Re: Generic Daemon Use by Zaxo (Archbishop) on Feb 03, 2007 at 01:21 UTC
A daemon does not have a controlling terminal, so your print statements should go to a particular file handle. You may not see a print to STDOUT unless you note what device you wish to display on and copy its handle. After Compline, Zaxo	[reply]
Re: Generic Daemon Use by Khen1950fx (Canon) on Feb 03, 2007 at 09:02 UTC
This worked for me. I used 'apt' instead: `#!/usr/bin/perl use strict; use warnings; use Daemon::Generic; my $sleeptime = 1 newdaemon( progname => 'apt', pidfile => '/var/run/apt.conf.pid', configfile => '/etc/apt.conf', ); sub gd_preconfig { my ($self) = @_; open(CONFIG, "</etc/apt.conf") while <CONFIG>; close(CONFIG); return (); } sub gd_run { while (1) { sleep($sleeptime); print scalar(localtime(time))."\n"; } }` [download] Note: I didn't use foreground. It went into an infinite loop. Use: `perl myscript.pl start`, then `perl myscript.pl check`. It'll give a pid number.	[reply] [d/l] [select]
Re^2: Generic Daemon Use by f00li5h (Chaplain) on Feb 03, 2007 at 13:54 UTC
I would have thought you'd want your daemon to run in an infinite loop (while waiting for Unix signals/sockets/alarms) Otherwise you've just got a normal perl script ... `@_=qw; ask f00li5h to appear and remain for a moment of pretend better than a lifetime;;s;;@_[map hex,split'',B204316D8C2A4516DE];;y/05/os/&print;`	[reply] [d/l]