Signals

Signals on database is a native Django signals.

Available variables for rules on Signals:

{{ date }} - current date
{{ date_time }} - current datetime
{{ site }} - current site
{{ domain }} - current site domain
{{ old_instance }} - old instance for pre_save
{{ current_instance }} - available when Update model state is enabled
{{ instance }} - instance from received signal
{{ ... }} - all instance fields as vars

When all signals was configured, you need to reload your wsgi application. Auto-reloading can be configured on settings by WSGI_AUTO_RELOAD/UWSGI_AUTO_RELOAD. But if you launch application on several instances, do it manually.

Note: Don’t use a big intervals, if deferred tasks on queue more than 3-4k. It can crash a celery worker.

For deferred tasks best way is a crontab command + database queue. You can add DB_MAILER_SIGNAL_DEFERRED_DISPATCHER = 'database' into project settings, and call crontab command send_dbmail_deferred_signal.