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https://issues.apache.org/jira/browse/AIRFLOW-267?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15351290#comment-15351290
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Chris Riccomini commented on AIRFLOW-267:
-----------------------------------------
Returning false does not halt the execution of a DAG. Returned values are
stored as XCom fields. From [XCom
docs|http://airflow.incubator.apache.org/concepts.html#xcoms]:
{quote}
In addition, if a task returns a value (either from its Operator’s execute()
method, or from a PythonOperator’s python_callable function), then an XCom
containing that value is automatically pushed.
{quote}
You should have a look at the BranchOperator to circumvent logic that you don't
want to run.
> PythonOperators return value seems to be ignored
> ------------------------------------------------
>
> Key: AIRFLOW-267
> URL: https://issues.apache.org/jira/browse/AIRFLOW-267
> Project: Apache Airflow
> Issue Type: Bug
> Components: operators
> Affects Versions: Airflow 1.7.0
> Reporter: Eric Johnson
> Priority: Minor
>
> This is a simple dag that I don't think should run to completion as there as
> a PythonOperator that returns False which should halt the dependency. Right?
> morning depends on check_false which depends on check_true.
> check_true's PythonOperator returns true. So that's fine. But check_false is
> a PythonOperator that returns False. Shouldn't that halt the execution?
> {code}
> from builtins import range
> from airflow.operators import BashOperator, DummyOperator, TimeSensor,
> PythonOperator
> from airflow.models import DAG
> from datetime import datetime, timedelta, time
> one_day_ago = datetime.combine(datetime.today() - timedelta(1),
> datetime.min.time())
> args = {
> 'owner': 'ejohnson',
> 'start_date' : one_day_ago,
> 'email' : "[email protected]",
> 'email_on_failure' : True
> }
> # This is the master container for the mydag
> mydag = DAG(
> dag_id='mydag',
> default_args=args,
> schedule_interval=None
> )
> def check_func_true(ds, **kwargs):
> return True
> def check_func_false(ds, **kwargs):
> return False
> check_false = PythonOperator(
> task_id='check_false',
> provide_context=True,
> python_callable=check_func_false,
> email="[email protected]",
> email_on_retry=True,
> email_on_failure=True,
> retries=5,
> dag=mydag)
> check_true = PythonOperator(
> task_id='check_true',
> provide_context=True,
> python_callable=check_func_true,
> email="[email protected]",
> email_on_retry=True,
> email_on_failure=True,
> retries=5,
> dag=mydag)
> morning = BashOperator(task_id='morning',bash_command="echo
> morning",dag=mydag)
> morning.set_upstream(check_false)
> check_false.set_upstream(check_true)
> {code}
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