dag
def my_py_command(ds, **kwargs):
print(kwargs)
print(kwargs.get('dag_run').conf.get('foo'))
print(" 'miff' was passed in via task params = {}".format(kwargs["params"]["miff"]))
logging.info(" 'miff' was passed in via task params = {}".format(kwargs["params"]["miff"]))
return 1
my_templated_command = """
echo " 'foo was passed in via Airflow CLI Test command with value {{ params.foo }} "
echo " 'miff was passed in via BashOperator with value {{ params.miff }} "
"""
run_this = PythonOperator(
task_id='run_this',
provide_context=True,
python_callable=my_py_command,
params={"miff":"agg"},
dag=dag)每个DAG 实例都有一个上下文的概念，以context参数的形式会透传给所有的任务，以及所有任务的回调函数。
context的内容----print(kwargs) 如下：
{
u'next_execution_date': None,
u'dag_run': ,
u'tomorrow_ds_nodash': u'20140215',
u'run_id': 'manual__2014-04-14T18:28:07',
u'dag': ,
u'prev_execution_date': None,
u'conf': ,
u'tables': None,
u'task_instance_key_str': u'example_passing_params_via_test_command__run_this__20140214',
u'END_DATE': '2014-04-14',
u'execution_date': datetime.datetime(2014, 2, 14, 18, 28, 7),
u'ts': '2014-02-14T18:28:07',
u'macros': ,
u'params': {'miff': 'agg'},
u'ti': ,
u'var': {u'json': None, u'value': None},
u'ds_nodash': u'20140214',
u'test_mode': False,
u'end_date': '2014-04-14',
'templates_dict': None,
u'task': ,
u'task_instance': ,
u'yesterday_ds_nodash': u'20140213',
u'latest_date': '2014-04-14',
u'yesterday_ds': '2014-04-13',
u'ts_nodash': u'20140214T182807',
u'tomorrow_ds': '2014-04-15'
} 实例参数使用pickle序列化存储在dag_run表中
字段类型如下
conf = Column(PickleType)
在执行PythonOperator时，会将上下文context参数，传递给回调函数中的self.op_kwargs
在执行Operator时，就可以从上下文实例中获取DagRun实例
kwargs.get('dag_run')
再从DagRun实例中获取conf参数，值为json对象类型
dag_run_conf = kwargs.get('dag_run').conf