How to debug WordPress “Cron” wp_schedule_event

Question

How can I debug problems with WordPress Cron? I think it will trigger when users go to your site but any errors wont be shown to them, as the jobs are run "asynchronously". So how might I debug errors?

I use wp schedule event

Answer 1

You can run WP cron manually by calling: http://example.com/wp-cron.php?doing_cron

If you don't want the automatic cron to run while you're debugging, then add this to your /wp-config.php file:

define('DISABLE_WP_CRON', true);

If you're on a development environment and want to output debug information, calling it manually like that will show you your debug output.

Alternatively you can use PHP's built-in error_log function to log message strings to the error log for debugging. You'd need to use this in conjunction with WP_DEBUG settings, as mentioned by Rarst.

Answer 2

You could use the plugin Cron-View. There you can see if your job is a) registered and b) what the next due time is.

In addition, you could add a lower schedule-timer to your event (e.g. every 2 min) and test your method more frequently on a local system. Use the 'cron_schedules' filter hook to register new schedule times. For example:

function my_additional_schedules($schedules) {
    // interval in seconds
    $schedules['every2min'] = array('interval' => 2*60, 'display' => 'Every two minutes');
    return $schedules;
}
add_filter('cron_schedules', 'my_additional_schedules');

Answer 3

You can (and probably should in any case, cron or not) configure PHP error log to capture all errors.