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Listeners
=========

Airflow gives you an option to be notified of events happening in Airflow
by writing listeners. Listeners are powered by `pluggy <https://pluggy.readthedocs.io/en/stable/>`__

Listener API is meant to be called across all dags, and all operators - in contrast to methods like
``on_success_callback``, ``pre_execute`` and related family which are meant to provide callbacks
for particular dag authors, or operator creators. There is no possibility to listen on events generated
by particular dag.

To include listener in your Airflow installation, include it as a part of an :doc:`Airflow Plugin </plugins>`

|experimental|

Interface
---------

To create a listener you will need to derive the
create python module, import ``airflow.listeners.hookimpl`` and implement the ``hookimpls`` for
events you want to be notified at.

Right now Airflow exposes TaskInstance state change events.
Their specification is defined as ``hookspec`` in ``airflow/listeners/spec.py`` file.