Crontab (Linux/CentOS 7) – More frequent than 1 minute

Setting up crontab

Open and edit crontab file

# crontab -e

Add this line (Change the path to your own)

*/1 * * * * sh /usr/bin/cronscript.sh >> /var/www/mywebpage/cron_log.log

This will open the cronscript.sh every minute.

Create a new shell-script file

#vi /usr/bin/cronscript.sh

The .sh script will open the cron.php every 15 secounds.

#!/bin/sh
/usr/bin/php -f /var/www/mywebpage/cron.php
sleep 15s
/usr/bin/php -f /var/www/mywebpage/cron.php
sleep 15s
/usr/bin/php -f /var/www/mywebpage/cron.php
sleep 15s

PHP cronjob manager

THIS IS NOT NEEDED TO USE CRONTAB – It’s just my own little crontab manager in PHP!
I like to add, edit and test cronjobs in my browser – and log when they was last runned. This is because I have some sync files, that could be called manually, like user-sync with AD LDAP. If new users are missing, I can at least check when the last sync was called. I can also run it manually from GUI.

SQL script

--
-- Tabellstruktur for tabell `system_cronjobs`
--

CREATE TABLE IF NOT EXISTS `system_cronjobs` (
`cron_id` int(11) NOT NULL,
`user_id` int(11) NOT NULL,
`title` varchar(128) NOT NULL,
`filepath` varchar(256) NOT NULL,
`interval` int(11) NOT NULL COMMENT 'interval in sec',
`run_on_day` tinyint(4) NOT NULL COMMENT 'Day (1-7) 1=monday, 7=sunday',
`run_on_time` int(4) unsigned zerofill NOT NULL COMMENT 'Time in day (ex 1600)',
`last_run` int(11) NOT NULL,
`disabled` tinyint(4) NOT NULL
) ENGINE=MyISAM AUTO_INCREMENT=8 DEFAULT CHARSET=latin1;

--
-- Dataark for tabell `system_cronjobs`
--

INSERT INTO `system_cronjobs` (`cron_id`, `user_id`, `title`, `filepath`, `interval`, `run_on_day`, `run_on_time`, `last_run`, `disabled`) VALUES
(1, 1, 'SMS: Check for new SMS', '/var/www/mywebpage/admin/modules/sms/cron/check_for_sms.php', 15, 0, 0000, 1421756852, 0);

cron.php
This script was written in just a few minutes and should NOT be used in a production enviroment without the knowledge to qualify it your self!

";
		echo "Time: " . date('Hi') . "
";
		echo "
";
	}


	$queryCronJobs = "SELECT * FROM system_cronjobs WHERE disabled='0'";
	$resultCronJobs = $mysqli->query($queryCronJobs);

	while ($rowCronJobs = $resultCronJobs->fetch_array()) {

		$runThis = false;
		$runThisDay = false;
		$runThisTime = false;

		if ($debug) echo "Running: {$rowCronJobs['title']}
";


		// Check timeinterval
		$timeDiff = (time() - $rowCronJobs['last_run']);

		if ($rowCronJobs['interval'] > 0) {
			if ($timeDiff > $rowCronJobs['interval']) {
				$runThis = true;
				if ($debug) echo "Run on this interval
";
			}
		}

		// Check day/time
		elseif (!empty($rowCronJobs['run_on_day']) || !empty($rowCronJobs['run_on_time'])) {
			if ($debug) echo "Run on day/time. Day:{$rowCronJobs['run_on_day']}, Time:{$rowCronJobs['run_on_time']}
";


			// If day matches
			if ($rowCronJobs['run_on_day'] > 0 && $rowCronJobs['run_on_day'] == date('N')) {
				$runThisDay = true;
				if ($debug) echo "Run on this day
";
			}

			// If time matches
			if ($rowCronJobs['run_on_time'] > 0 && $rowCronJobs['run_on_time'] == date('Hi')) {
				$runThisTime = true;
				if ($debug) echo "Run on this time
";
			}



			// Both day and time
			if ($rowCronJobs['run_on_day'] > 0 && $rowCronJobs['run_on_time'] > 0) {
				if ($runThisDay == true && $runThisTime == true) $runThis = true;

				if ($runThis == true && $timeDiff < (86400 + 100)) $runThis = false; // Check min interval to prevent spamming
			}

			// Only day
			elseif ($rowCronJobs['run_on_day'] > 0 && $rowCronJobs['run_on_time'] == 0) {
				if ($runThisDay == true && $runThisTime == false) $runThis = true;

				if ($runThis == true && $timeDiff < (86400 + 100)) $runThis = false; // Check min interval to prevent spamming
			}

			// Only time
			elseif ($rowCronJobs['run_on_day'] == 0 && $rowCronJobs['run_on_time'] > 0) {
				if ($runThisDay == false && $runThisTime == true) $runThis = true;

				if ($runThis == true && $timeDiff < (120)) $runThis = false; // Check min interval to prevent spamming
			}
		}


		// Run cronjobs
		if ($runThis == true) {
			if ($debug) echo "Run this == TRUE
";


			// Update last run timestamp
			$queryUpdateCronJobs = "UPDATE system_cronjobs SET 
						last_run='". time() ."'
						WHERE cron_id='".$rowCronJobs['cron_id']."'";
			$resultUpdateCronJobs = $mysqli->query($queryUpdateCronJobs);



			//include(ABSPATH . $rowCronJobs['filepath']);
			include($rowCronJobs['filepath']);

			

			if ($debug) echo "result2: $resultUpdateCronJobs 
";
			if ($debug) echo "query2: $queryUpdateCronJobs 
";
		}

		else {
			if ($debug) echo "Run this == FALSE
";
		}

		if ($debug) echo "
";		
	}
?>