Listing 4. Monitor.pl
# !/usr/bin/perl
$URLToPing = $ARGV[0];
$PIN = $ARGV[1];
$Delay = $ARGV[2];
$RetryDelay = $ARGV[3];
$Debug = $ARGV[4];
$HTTPping = "/bin/HTTPping.pl";
print "URL = $URLToPing\n" if ($Debug ==1);
print "Pin = $PIN\n" if ($Debug==1);
print "Delay = $Delay seconds\n" if ($Debug==1);
print "Retry Delay = $RetryDelay seconds\n" if ($Debug==1);
# sleep a random amount up to one delay period
# this helps 'spread out' multiple instances of
# script running
simultaneously
# sleep(int(rand($Delay)) + 1);
# start out using the current ping result as the
# current server status
$HTTPPingResult = HTTPPing($URLToPing);
$ServerStatus = $HTTPPingResult;
# send a page when the monitor starts
SendPage("Monitor for $URLToPing up at " .
localtime(), $PIN);
if ($ServerStatus == 1) {
SendPage("$URLToPing is UP at startup " .
localtime(), $PIN);
} else {
SendPage("$URLToPing is DOWN at startup " .
localtime(), $PIN);
}
# loop indefinately, checking the site and paging
# if necessary
while (1==1) {
# HTTP ping the site
$HTTPPingResult = HTTPPing($URLToPing);
print "ServerStatus = $ServerStatus\n"
if ($Debug == 1);
print "HTTPPingResult = $HTTPPingResult\n"
if ($Debug == 1);
# check to see if the site went down
if (($ServerStatus == 1) and
($HTTPPingResult == 0)) {
print
"The site appears down, waiting to verify.\n"
if ($Debug == 1);
sleep($RetryDelay);
# re-ping the site
$HTTPPingResult = HTTPPing($URLToPing);
if ($HTTPPingResult == 0) {
print " Verified. site down\n";
$ServerStatus = 0;
SendPage("$URLToPing is DOWN " .
localtime(), $PIN);
} else {
print "Did not verify, site still up\n";
}
}
# check to see if the site is up
if (($ServerStatus == 0) and
($HTTPPingResult == 1)) {
$ServerStatus = 1;
print "$URLToPing up at " .
localtime() . "\n" if ($Debug ==1);
SendPage("$URLToPing is UP at " .
localtime(), $PIN);
}
# wait between pings
sleep ($Delay);
}
sub HTTPPing {
print "HTTPPing called\n" if ($Debug == 1);
my $URL = $ARGV[0];
$command = "$HTTPping $URL";
my $pingresult = system($command)/256;
return $pingresult;
}
sub SendPage {
use HTTP::Request::Common;
require LWP::UserAgent;
my ($Message, $PIN) = @_;
$to = "$PIN,1";
$ua = new LWP::UserAgent;
$req = POST
'http://204.71.160.11/destineer/ss_paging.cgi',
[ cmd => 'send',
to => $to,
msg => $Message];
$response = $ua->request($req);
}
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