Update documentation priority weight (apache#47529)

Author: azharizz

airflow/example_dags/example_custom_weight.py

@@ -0,0 +1,57 @@
+#
+# 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.
+"""Example DAG demonstrating the usage of the CustomWeightRule."""
+
+from __future__ import annotations
+
+import datetime
+
+import pendulum
+from airflow.example_dags.plugins.decreasing_priority_weight_strategy import DecreasingPriorityStrategy
+
+# [START example_custom_weight_dag]
+from airflow.models.dag import DAG
+from airflow.providers.standard.operators.bash import BashOperator
+from airflow.providers.standard.operators.empty import EmptyOperator
+
+with DAG(
+    dag_id="example_custom_weight",
+    schedule="0 0 * * *",
+    start_date=pendulum.datetime(2021, 1, 1, tz="UTC"),
+    catchup=False,
+    dagrun_timeout=datetime.timedelta(minutes=60),
+    tags=["example", "example2"],
+) as dag:
+    start = EmptyOperator(
+        task_id="start",
+    )
+
+    # provide the class instance
+    task_1 = BashOperator(task_id="task_1", bash_command="echo 1", weight_rule=DecreasingPriorityStrategy())
+
+    # or provide the path of the class
+    task_2 = BashOperator(
+        task_id="task_2",
+        bash_command="echo 1",
+        weight_rule="airflow.example_dags.plugins.decreasing_priority_weight_strategy.DecreasingPriorityStrategy",
+    )
+
+    task_non_custom = BashOperator(task_id="task_non_custom", bash_command="echo 1", priority_weight=2)
+
+    start >> [task_1, task_2, task_non_custom]
+# [END example_custom_weight_dag]

docs/apache-airflow/administration-and-deployment/priority-weight.rst

@@ -84,21 +84,18 @@ registering it in a plugin.
     :end-before: [END custom_priority_weight_strategy]
 
 
-Then to use it, you can create an instance of the custom class and provide it in the ``weight_rule`` parameter
-of the task or provide the path of the custom class:
+To check if the custom priority weight strategy is already available in Airflow, you can run the bash command
+``airflow plugins``. Then to use it, you can create an instance of the custom class and provide it in the
+``weight_rule`` parameter of the task or provide the path of the custom class:
 
-.. code-block:: python
-
-    from custom_weight_rule_module import CustomPriorityWeightStrategy
+.. exampleinclude:: /../../airflow/example_dags/example_custom_weight.py
+    :language: python
+    :dedent: 0
+    :start-after: [START example_custom_weight_dag]
+    :end-before: [END example_custom_weight_dag]
 
-    # provide the class instance
-    task1 = BashOperator(task_id="task", bash_command="echo 1", weight_rule=CustomPriorityWeightStrategy())
 
-    # or provide the path of the class
-    task1 = BashOperator(
-        task_id="task",
-        bash_command="echo 1",
-        weight_rule="custom_weight_rule_module.CustomPriorityWeightStrategy",
-    )
+After the DAG is running, you can check the ``priority_weight`` parameter on the task to verify that it is using
+the custom priority strategy rule.
 
 |experimental|