providers/http/docs/deferrable.rst

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.. _howto/deferrable:HttpOperator:

Deferrable HttpOperator
=======================

:class:`~airflow.providers.http.operators.http.HttpOperator` can run in deferrable mode
(``deferrable=True``, or via ``[operators] default_deferrable``). In that mode the operator
defers immediately and the HTTP request is executed in the Triggerer by
:class:`~airflow.providers.http.triggers.http.HttpTrigger`.

Triggerer restart can replay the request
----------------------------------------

The Triggerer persists trigger kwargs and reconstructs the trigger after a restart.
``HttpTrigger.run()`` then issues the HTTP request again. That is safe for
idempotent methods and unsafe for methods that create a new side effect on every
call (the operator default is ``POST``).

HttpOperator treats these methods as idempotent, matching RFC 9110 §9.2.2:

* ``GET``
* ``HEAD``
* ``OPTIONS``
* ``PUT``
* ``DELETE``
* ``TRACE``

``POST``, ``PATCH``, and any other method emit one task-log warning per attempt
when used with deferrable mode.

Silencing the warning
---------------------

If a duplicate request is acceptable for your endpoint, set
``warn_on_non_idempotent=False``:

.. code-block:: python

    HttpOperator(
        task_id="create_resource",
        method="POST",
        endpoint="/resources",
        deferrable=True,
        warn_on_non_idempotent=False,
    )

Safer alternatives for polling or waiting on an HTTP condition are
:class:`~airflow.providers.http.sensors.http.HttpSensor` or an event-driven
trigger such as :class:`~airflow.providers.http.triggers.http.HttpEventTrigger`.
For a one-shot non-idempotent call, prefer ``deferrable=False`` so the worker
issues the request once.

This page is the target of the task-log warning. The warning does not prevent a
duplicate request; it only tells Dag authors that a Triggerer restart can replay
it.