Send alert message using telegram message when someone connect to anyconnect VPN

cisco-ftd-log-anyconnect-alert.pl

#!/usr/bin/perl -w-

use strict;
use warnings;

my $DEBUG = 0;
my $RUNFILE = "/var/tmp/ftd-logmon.run";

my $ALRT = "ALRT";
$ALRT =  "CJ" if ($DEBUG);

sub init() {
	if ( -f $RUNFILE ) {
		open my $f, '<', "$RUNFILE" or die "Can't open $RUNFILE";
		my $pid = <$f>;
		chomp($pid);
		close $f;

		die "Another process [ $pid ] is running" if -d "/proc/$pid";
	}
	my $pid = fork();

	if ($pid != 0) {
		open my $f, '>', "$RUNFILE" or die "Can't open $RUNFILE : $!";
		print $f "$pid";
		close $f;
		exit;
	}
}

sub close_and_exit() {
        print "Terminated\n";
        exit(0);
}

sub send_message() {
	my ($mesg) = @_;
	print "send: $mesg\n" if $DEBUG;
	system("/home/cj/bin/bot_sendmsg2 $ALRT '$mesg'");
}

$SIG{USR1} = sub(){ exit(0); };

### Start Here ###

&init();

my $logfile = "/var/log/cisco-ftd.log";
$logfile = $ARGV[0] if defined($ARGV[0]);

my $sz = (stat $logfile)[7];

# $sz = 0 if $DEBUG;
open my $f, '<', "$logfile";

while (1) {
        my $newsz = (stat $logfile)[7];
        if ($newsz == $sz) {
                sleep(1);
        } else {
                if ($newsz < $sz) {
                        &send_message("Size reduced, log file reopen");
                        close($f);
                        open $f, '<', "$logfile";
                } else {
					while (<$f>) {
						next unless /%FTD-auth-6-113039|%FTD-auth-4-113019|%FTD-session-6-302021/;
						if (/%FTD-auth-6-113039/) {
							my ($tstamp, $user, $ip) = (/^(.{15}).+User <(.+?)> IP <(.+?)>/);
							&send_message("$tstamp, $user, $ip\n");
						}
						if (/%FTD-auth-4-113019/) {
							my ($tstamp, $user, $ip, $duration, $xmt, $rcv, $reason) = 
							(/^(.{15}).+Username = (.+?), IP = (.+?),.+ Duration: (.+?),.+ xmt: (.+),.+ rcv: (.+?), Reason: (.+)$/);
							&send_message("$tstamp, $user, $ip, $duration, $xmt, $rcv, $reason");
						}
						# for debug only
						if ($DEBUG && /%FTD-session-6-302021/) {
							my ($faddr,$gaddr,$laddr) = (/faddr ([0-9.]+).+gaddr ([0-9.]+).+laddr ([0-9.]+)/);
							&send_message("$faddr, $gaddr, $laddr");
						}
					}
                }
                $sz = $newsz;
        }
}

1;