The Datewatch plugin allows other Moodle plugins to execute a callback every time some date occurs.

For example, plugins can monitor such things as "course enrolment ended", "2 days before the due date", etc.

To use, add this callback it in your plugin's lib.php:

function YOURPLUGINNAME_datewatch() {
    $watchers = [];

    // Example 1: Send notification when course enrolment ended.

    $watchers[] = \tool_datewatch\watcher::instance('user_enrolments', 'timeend')
        ->set_callback(function(\tool_datewatch\notification $notification) {
            if ($userenrolment = $notification->get_record()) {
                $enrol = $notification->get_snapshot('enrol', $userenrolment->enrolid);
                YOURPLUGINNAME_send_notification_enrollment_ended($userenrolment->userid, $enrol->courseid);
            }
        });

    // Example 2: Do something 3 days before assignment due date.

    $watchers[] = \tool_datewatch\watcher::instance('assign', 'duedate', - 3 * DAYSECS)
        ->set_callback(function(\tool_datewatch\notification $notification) {
            // ...
        });
        
    return $watchers;
}

• The watched date has to be a field in a database table plus/minus a fixed offset (i.e. "7 days before the due date");
• There must be events triggered every time a record is added, updated or deleted in the respective database table and this event must have correct `objecttable` and `objectid` properties.

For more details refer to the README.md file in the plugin

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This plugin has been contributed and is maintained by the Moodle Workplace team.