Template php nagios check

check_things.php

<?php
# Template php nagios check
#
# Meant to work along with nagios's check_http. In addition to the
# returned string which is a standard nagios result, the script returns
# 403 and 503 errors on WARNING and CRITICAL respectively to make
# check_http return an equivalent status. The HTTP status printed by
# check_http is also the script result.
#
# Author: Thomas Guyot-Sionnest <tguyot@gmail.com>
#

ini_set('display_errors', '0');

### Config

# Default thresholds
$warn = 60;
$crit = 300;

# Things to check
$things = array(
	'foo' => 0,
	'bar' => 1,
	'baz' => 2,
);

###

// Exit wrapper function
function nagios_exit($code, $message, $perf='') {
	switch ($code) {
	case 0:
		$err = 'OK';
		header('HTTP/1.1 200 '."$err: $message\n");
		break;
	case 1:
		$err = 'WARNING';
		header('HTTP/1.1 403 '."$err: $message\n");
		break;
	case 2:
		$err = 'CRITICAL';
		header('HTTP/1.1 503 '."$err: $message\n");
		break;
	default:
		header('HTTP/1.1 400 Bad Request');
		$err = 'UNKNOWN';
	}
	header('Content-Type: text/plain');
	echo "$err: $message |$perf\n";
	exit();
}

if (isset($_REQUEST['thing']) && isset($things[$_REQUEST['thing']])) {
	$type = $_REQUEST['thing'];
	$thing = $things[$type];
} else {
	nagios_exit(3, 'Missing or invalid `thing\' parameter');
}

if (isset($_REQUEST['value'])) {
	if (is_numeric($_REQUEST['value'])) {
		$value = $_REQUEST['value'];
	} else {
		nagios_exit(3, 'Invalid `value\' parameter');
	}
} else {
	nagios_exit(3, 'Missing `value\' parameter');
}

if (isset($_REQUEST['warn'])) {
	if (is_numeric($_REQUEST['warn'])) {
		$warn = $_REQUEST['warn'];
	} else {
		nagios_exit(3, 'Invalid `warn\' parameter');
	}
}

if (isset($_REQUEST['crit'])) {
	if (is_numeric($_REQUEST['crit'])) {
		$crit = $_REQUEST['crit'];
	} else {
		nagios_exit(3, 'Invalid `crit\' parameter');
	}
}

try {
	// Do real stuff here...
	$res = $thing * $value;

} catch (Exception $e) {
	nagios_exit(3, 'Shit happens: '.$e);
}

$ret = 3;
if ($res >= $crit) {
	$ret = 2;
} else if ($res >= $warn) {
	$ret = 1;
} else if ($res >= 0) {
	$ret = 0;
}

nagios_exit($ret, $type.'value is '.$res, 'thing='.$res.'s;'.$warn.';'.$crit.';0;');