Sometimes you don't want Rules to carry out the actions when a triggering event occurs, but at some later point in time. A site with events, for example, may find it useful to send reminders 24 hours before an event occurs.
Rules Scheduler (included in the Rules project) allows you to schedule actions at selected points in time. It is used like this:

  • A number of actions, rules or rule sets are prepared as rule components.
  • A reaction rule (or some other part of Drupal capable of using Rules actions) is configured to schedule the selected rule component.
  • The scheduling involves setting an ID for the scheduled task, a time when it should be performed and selecting any objects that should be sent as variables to the component.
  • Once the configured time has been reached, your site will load the scheduled task and execute it.

TIP: The scheduled tasks are not actually executed right at the scheduled time, but at the nearest following cron run. Depending on your server setup it may take a few minutes or up to an hour between the scheduled time and the actual execution.