#!/usr/bin/perl
use strict;
##################################################################
# Script downloaded from http://www.nerdgirl.dk/qa/server_load.txt
# # Author: Jette Nielsen ( nerdgirl at nerdgirl dot dk)
# # Created: 2004-12-12      Last update: 2005-06-28
# # Description: This script will report if the CPU load exceeds
# #              a certain percentage ($limit)
# # ----------------------------------------------------------------
# # 1. Save this script in a file called server_load.pl owned by root
# #    Change the value of $max_load, to one of your choice
# # 2. Make sure that the script is executable by the owner: 
# #    'chmod u+x server_load.pl'
# # 3. Create the entry in the crontab of the root user, and make it
# #    run as often as you like, e.g. every 5 minutes:
# #    0-59/5 * * * * /path/to/server_load.pl | mail -s "Server load" email@domain.tld
# #
# # Feel free to make any changes ... do not forget to mail me, if 
# # you think of something brilliant :-)
# # ################################################################
# 
my $max_load = 50;

# Call top and get all links beneath the headings line
my $top = `/usr/bin/top -b -n`; 
$top =~ s/^.+?PID[^\n]+\n//s; 

# Then put all proccesses into an array... 
my @procs = split(/\n/, $top); 

my @procval = ();
my @excee = ();
my $total;

# Loop through each process
if (@procs > 0) {
	foreach my $value (@procs) {
  	@procval = split /\s+/, $value;
		$procval[9] =~ /(\d+)/;
		$total += $1;
		if ($1 > 0) {
			push (@excee,$value);
		}
	}
}

my $start;
my $stop;

# Is the limit exceeded?
if ($total > 50) {
	print "CPU usage limit exceeded: $total\n\n";
	print join("\n",@excee)."\n\n";
	# Limit is exceeded, try to restart apache
	$stop = `/usr/local/sbin/apachectl stop`;
	if ($stop =~ /httpd stopped$/) {
		$start = `/usr/local/sbin/apachectl start`;
		if ($start =~ /httpd started$/) {
			print "Apache was successfully restarted\n";
		} else {
			print "Could not restart apache:\n$start\n";
		}
	} else {
		print "Could not stop apache:\n$stop\n";
	}
}