Signals in Django

One of the benefits of the app structure of Django is that disparate pieces of your project don’t necessarily know about each other. But sometimes something happening in one app needs to trigger an action in another. Signals to the rescue.

Built in Signals

Some signals, such as post_save, come built in. They are called every time an instance of their sender is saved. For example:

@receiver(post_save, sender='app.Model', dispatch_uid='example_method')
def example_method(sender, instance=None, created=None, update_fields=None, **kwargs)…