# # 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. """ ### Tutorial Documentation Documentation that goes along with the Airflow tutorial located [here](https://airflow.apache.org/tutorial.html) """ from __future__ import annotations # [START tutorial] # [START import_module] import textwrap from datetime import datetime, timedelta # The DAG object; we'll need this to instantiate a DAG from airflow.models.dag import DAG # Operators; we need this to operate! from airflow.operators.bash import BashOperator # [END import_module] # [START instantiate_dag] with DAG( "tutorial", # [START default_args] # These args will get passed on to each operator # You can override them on a per-task basis during operator initialization default_args={ "depends_on_past": False, "email": ["airflow@example.com"], "email_on_failure": False, "email_on_retry": False, "retries": 1, "retry_delay": timedelta(minutes=5), # 'queue': 'bash_queue', # 'pool': 'backfill', # 'priority_weight': 10, # 'end_date': datetime(2016, 1, 1), # 'wait_for_downstream': False, # 'sla': timedelta(hours=2), # 'execution_timeout': timedelta(seconds=300), # 'on_failure_callback': some_function, # or list of functions # 'on_success_callback': some_other_function, # or list of functions # 'on_retry_callback': another_function, # or list of functions # 'sla_miss_callback': yet_another_function, # or list of functions # 'on_skipped_callback': another_function, #or list of functions # 'trigger_rule': 'all_success' }, # [END default_args] description="A simple tutorial DAG", schedule=timedelta(days=1), start_date=datetime(2021, 1, 1), catchup=False, tags=["example"], ) as dag: # [END instantiate_dag] # t1, t2 and t3 are examples of tasks created by instantiating operators # [START basic_task] t1 = BashOperator( task_id="print_date", bash_command="date", ) t2 = BashOperator( task_id="sleep", depends_on_past=False, bash_command="sleep 5", retries=3, ) # [END basic_task] # [START documentation] t1.doc_md = textwrap.dedent( """\ #### Task Documentation You can document your task using the attributes `doc_md` (markdown), `doc` (plain text), `doc_rst`, `doc_json`, `doc_yaml` which gets rendered in the UI's Task Instance Details page. ![img](https://imgs.xkcd.com/comics/fixing_problems.png) **Image Credit:** Randall Munroe, [XKCD](https://xkcd.com/license.html) """ ) dag.doc_md = __doc__ # providing that you have a docstring at the beginning of the DAG; OR dag.doc_md = """ This is a documentation placed anywhere """ # otherwise, type it like this # [END documentation] # [START jinja_template] templated_command = textwrap.dedent( """ {% for i in range(5) %} echo "{{ ds }}" echo "{{ macros.ds_add(ds, 7)}}" {% endfor %} """ ) t3 = BashOperator( task_id="templated", depends_on_past=False, bash_command=templated_command, ) # [END jinja_template] t1 >> [t2, t3] # [END tutorial]