Small example using syslog()

emaillog.pl

#!/usr/bin/perl -n
# thanks to Brian Dowling for an example with security in mind.

$TO = ‘root@localhost’;
$FROM = $TO;

s/^<\d{1,2}>//;

open(MAIL, “|/usr/sbin/sendmail -t”);

print MAIL <<”EOT”;
To: $TO
From: $FROM
Subject: Log Alert: $_

$_

EOT

example1.php

<?php

 openlog('myapplication', LOG_NDELAY, LOG_USER);
 syslog(LOG_NOTICE, "Something has happened");
 syslog(LOG_ERR, "Something bad has happened");

?>

syslog-ng.conf

destination df_userapp { file("/var/log/userapp.log"); };

filter f_userapp { program("myapplication"); };

log {
  source(s_all);
  filter(f_userapp);
  destination(df_userapp);
};

syslog-ng2.conf

destination dm_userapp { program("/usr/local/sbin/maillog.pl"); };

filter f_userapp { program("myapplication"); };

log {
  source(s_all);
  filter(f_userapp);
  filter(f_at_least_err);
  destination(dm_userapp);
};

syslog-ng3.conf

destination d_loghost { udp("192.168.1.100" port(514)); };

filter f_userapp { program("myapplication"); };

log {
  source(s_all);
  filter(f_userapp);
  destination(d_loghost);
};