uranusjr commented on code in PR #32169:
URL: https://github.com/apache/airflow/pull/32169#discussion_r1247415859
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docs/apache-airflow/core-concepts/dags.rst:
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@@ -484,6 +484,125 @@ You can also combine this with the
:ref:`concepts:depends-on-past` functionality
.. image:: /img/branch_with_trigger.png
+.. _concepts:setup-and-teardown:
+
+Setup and Teardown
+~~~~~~~~~~~~~~~~~~
+
+In data workflows it's common to create resources (such as a compute
resource), use it to do some work, and then tear it down. Airflow provides
setup and teardown tasks to support this need.
+
+Key features of setup and teardown tasks:
+
+ * If you clear a task, its setups and teardowns will be cleared.
+ * By default, teardown tasks are ignored for the purpose of evaluating dag
run state.
+ * A teardown task will run if it's setup was successful, even if its work
tasks failed.
+ * Teardown tasks are ignored when setting dependencies against task groups.
+ * A setup task must always have a teardown and vice versa. You may use
EmptyOperator as a setup or teardown.
+
+Basic usage
+"""""""""""
+
+Suppose you have a dag that creates a cluster, runs a query, and deletes the
cluster. Without using setup and teardown tasks you might set these
relationships:
+
+.. code-block:: python
+
+ create_cluster >> run_query >> delete_cluster
+
+We can use the ``as_teardown`` let airflow know that ``create_cluster`` is a
setup task and ``delete_cluster`` is its teardown:
+
+.. code-block:: python
+
+ create_cluster >> run_query >>
delete_cluster.as_teardown(setups=create_cluster)
+
+Observations:
+
+ * If you clear ``run_query`` to run it again, then both ``create_cluster``
and ``delete_cluster`` will be cleared.
+ * If ``run_query`` fails, then ``delete_cluster`` will still run.
+ * The success of the dag run will depend on the success of ``run_query``.
+
+Setup "scope"
+"""""""""""""
+
+We require that a setup always have a teardown in order to have a well-defined
scope. If you wish to only add a teardown task or only a setup task, you may
use EmptyOperator as your "empty setup" or "empty teardown".
+
+The "scope" of a setup will be determined by where the teardown is. Tasks
between a setup and its teardown are in the "scope" of the setup / teardown
pair. Example:
+
+.. code-block:: python
+
+ s1 >> w1 >> w2 >> t1.as_teardown(setups=s1) >> w3
+ w2 >> w4
Review Comment:
This indentation is not consistent. Do we want to indent by two or four in
this document?
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