Django events provides a simple mechanism for defining and responding to events in django.

The mechanism is similar to signals and in some cases should replace them.

• Declarative definition of the events and their listeners in the settings. The developer defines all events and their listeners in the settings file and the app is responsible to expose them in the other apps.

• Base classes for actions that deal with the most common cases. Specifically:

  • Responding to events with a plain function.
  • Responding to events in a celery task.
  • Responding to events, only if a condition is met.
  • Responding to events, only when the event signals a status change.

• Easier testing; the developer can remove all listeners for the events, when running the tests.

There are cases where certain things in an application have status, e.g. tests passing or not. In such cases you might want to notify the users, only when the status changes, i.e. going from "tests passing" to "tests failing" and the other way round.

The EdgeTriggeredAction class provides this feature.

First, add the app in the INSTALLED_APPS and define the events and their listeners in the settings file:

INSTALLED_APPS += ['events']

EVENTS = {
    'tests_pass': [
        'myapp.actions.Action1',
        'myapp.actions.Action2',
    ]
}

Then, in the place you want to emit the event, do:

from events.models import tests_pass

tests_pass.emit(args)

In the myapp.actions module define the two actions:

from events.actions import Action

class Action1(Action):
    pass


class Action2(Action):
    pass