Doc: Add concrete examples for accessing context variables from TaskFlow tasks (apache#33296)

Author: RNHTTR

docs/apache-airflow/core-concepts/taskflow.rst

@@ -66,9 +66,16 @@ If you want to learn more about using TaskFlow, you should consult :doc:`the Tas
 Context
 -------
 
-When running your callable, Airflow will pass a set of keyword arguments that can be used in your function. This set of kwargs correspond exactly to the :ref:`context variables<templates:variables>` you can use in your Jinja templates.
+You can access Airflow :ref:`context variables <templates:variables>` by adding them as keyword arguments as shown in the following example:
+
+.. include:: ../../shared/template-examples/taskflow.rst
+
+Alternatively, you may add ``**kwargs`` to the signature of your task and all Airflow context variables will be accessible in the ``kwargs`` dict:
+
+.. include:: ../../shared/template-examples/taskflow-kwargs.rst
+
+For a full list of context variables, see :ref:`context variables <templates:variables>`.
 
-For this to work, you need to define ``**kwargs`` in your function header, or you can add directly the keyword arguments you would like to get such as ``ti=None`` to have the task instance passed.
 
 Logging
 -------

docs/apache-airflow/templates-ref.rst

@@ -81,6 +81,18 @@ Variable                                    Type                  Description
     The DAG run's logical date, and values derived from it, such as ``ds`` and
     ``ts``, **should not** be considered unique in a DAG. Use ``run_id`` instead.
 
+Accessing Airflow context variables from TaskFlow tasks
+-------------------------------------------------------
+
+While ``@task`` decorated tasks don't support rendering jinja templates passed as arguments,
+all of the variables listed above can be accessed directly from tasks. The following code block
+is an example of accessing a ``task_instance`` object from its task:
+
+.. include:: ../shared/template-examples/taskflow.rst
+
+Deprecated variables
+-------------------------------------------------------
+
 The following variables are deprecated. They are kept for backward compatibility, but you should convert
 existing code to use other variables instead.
 

docs/shared/template-examples/taskflow-kwargs.rst

@@ -0,0 +1,27 @@
+ .. Licensed to the Apache Software Foundation (ASF) under one
+    or more contributor license agreements.  See the NOTICE file
+    distributed with this work for additional information
+    regarding copyright ownership.  The ASF licenses this file
+    to you under the Apache License, Version 2.0 (the
+    "License"); you may not use this file except in compliance
+    with the License.  You may obtain a copy of the License at
+
+ ..   http://www.apache.org/licenses/LICENSE-2.0
+
+ .. Unless required by applicable law or agreed to in writing,
+    software distributed under the License is distributed on an
+    "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+    KIND, either express or implied.  See the License for the
+    specific language governing permissions and limitations
+    under the License.
+
+ .. code-block:: python
+
+    @task
+    def print_ti_info(**kwargs):
+        ti = kwargs["task_instance"]
+        print(f"Run ID: {ti.run_id}")  # Run ID: scheduled__2023-08-09T00:00:00+00:00
+        print(f"Duration: {ti.duration}")  # Duration: 0.972019
+
+        dr = kwargs["dag_run"]
+        print(f"DAG Run queued at: {dr.queued_at}")  # 2023-08-10 00:00:01+02:20

docs/shared/template-examples/taskflow.rst

@@ -0,0 +1,24 @@
+ .. Licensed to the Apache Software Foundation (ASF) under one
+    or more contributor license agreements.  See the NOTICE file
+    distributed with this work for additional information
+    regarding copyright ownership.  The ASF licenses this file
+    to you under the Apache License, Version 2.0 (the
+    "License"); you may not use this file except in compliance
+    with the License.  You may obtain a copy of the License at
+
+ ..   http://www.apache.org/licenses/LICENSE-2.0
+
+ .. Unless required by applicable law or agreed to in writing,
+    software distributed under the License is distributed on an
+    "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+    KIND, either express or implied.  See the License for the
+    specific language governing permissions and limitations
+    under the License.
+
+ .. code-block:: python
+
+    @task
+    def print_ti_info(task_instance=None, dag_run=None):
+        print(f"Run ID: {task_instance.run_id}")  # Run ID: scheduled__2023-08-09T00:00:00+00:00
+        print(f"Duration: {task_instance.duration}")  # Duration: 0.972019
+        print(f"DAG Run queued at: {dag_run.queued_at}")  # 2023-08-10 00:00:01+02:20