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Posted to dev@airflow.apache.org by Jason Chen <ch...@gmail.com> on 2016/07/01 18:35:51 UTC

Questions about upstreams

Hi,
 Airflow is great to allow setting multiple upstream tasks.
 Say, task3 can have [task1, task2] as upstreams.
 My understanding is that task3 will be triggered only BOTH task1 and task2
are successful.
 Is that right ?

 Thanks.

Jason

Re: Questions about upstreams

Posted by Arthur Wiedmer <ar...@gmail.com>.

Hi Jason,

You understand right, this is the default behavior. We also have the
concept of trigger_rule which allows for more flexible rules, including: at
least one success, at least one failure etc...

You can see the code here :
https://github.com/apache/incubator-airflow/blob/master/airflow/utils/trigger_rule.py

Best,
Arthur

On Fri, Jul 1, 2016 at 11:35 AM, Jason Chen <ch...@gmail.com>
wrote:

> Hi,
>  Airflow is great to allow setting multiple upstream tasks.
>  Say, task3 can have [task1, task2] as upstreams.
>  My understanding is that task3 will be triggered only BOTH task1 and task2
> are successful.
>  Is that right ?
>
>  Thanks.
>
> Jason
>