note
cees
<p>Using [module://Proc::PID_File] and [module://Proc::Daemon] should get you most of the way there. Here is a chopped down version of a daemon script that I use, complete with logging. Hope it is a helpful starting point.</p>
<code>
#!/usr/bin/perl
use strict;
use warnings;
use constant LOG_DIR => '/var/log/mydaemon';
use constant LOG_FILE => 'mydaemon.log';
use constant PIDDIR => LOG_DIR;
use Proc::PID_File;
use Proc::Daemon;
use Log::Dispatch;
use Log::Dispatch::File;
use Date::Format;
use File::Spec;
sub dienice ($);
#
# fork and background process
#
our $ME = $0; $ME =~ s|.*/||;
our $PIDFILE = PIDDIR."/$ME.pid";
startDaemon();
#
# Setup a logging agent
#
our $HOSTNAME = `hostname`;
chomp $HOSTNAME;
my $log = new Log::Dispatch(
callbacks => sub { my %h=@_; return Date::Format::time2str('%B %e %T', time)." ".$HOSTNAME." $0\[$$]: ".$h{message}."\n"; }
);
$log->add( Log::Dispatch::File->new( name => 'file1',
min_level => 'warning',
mode => 'append',
filename => File::Spec->catfile(LOG_DIR, LOG_FILE),
)
);
$log->warning("Starting Processing: ".time());
#
# Setup signal handlers so that we have time to cleanup before shutting down
#
my $keep_going = 1;
$SIG{HUP} = sub { $log->warning("Caught SIGHUP: exiting gracefully"); $keep_going = 0; };
$SIG{INT} = sub { $log->warning("Caught SIGINT: exiting gracefully"); $keep_going = 0; };
$SIG{QUIT} = sub { $log->warning("Caught SIGQUIT: exiting gracefully"); $keep_going = 0; };
#$SIG{TERM} = sub { $log->warning("Caught SIGTERM: exiting gracefully"); $keep_going = 0; };
#
# enter main loop
#
while ($keep_going) {
# do something useful here
}
#
# Mark a clean exit in the log
#
$log->warning("Stopping Processing: ".time());
#
# startDaemon
#
# Fork and detach from the parent process
#
sub startDaemon {
#
# Fork and detach from the parent process
#
# eval { close DATA; }; # having __END__ will trigger __DATA__ to open and should be closed
eval { Proc::Daemon::Init; };
if ($@) {
dienice("Unable to start daemon: $@");
}
#
# Get a PID file
#
dienice("Already running!") if hold_pid_file($PIDFILE);
}
#
# dienice
#
# write die messages to the log before die'ing
#
sub dienice ($) {
my ($package, $filename, $line) = caller;
$log->critical("$_[0] at line $line in $filename");
die $_[0];
}
</code>
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