Drupal 8 Module Development

Cron based queue

In the previous section, we wrote the sports_cron() implementation, which at each run looks for teams that no longer have players and deletes them from the database. However, if we run the Drupal cron every hour, we keep running that query even if we are pretty certain that teams don't loose all their players so often. Moreover, we also go by the simple assumption (a functionality we have not written so far) that there is some code responsible for removing a player from a team. This would actually be the ideal place to check if that team has lost all its players. The idea, then, is to check if the team has been left empty and add it to a queue to be deleted later (whenever the cron runs).

We won't go into the code specific ...