CODEWITHSUNDEEP
airflowairflow-scheduler
rcorre
rcorre

Reputation: 7238

What start_date should I use for a manually triggered DAG?

Many of the airflow example dags that have schedule_interval=None set a dynamic start date like airflow.utils.dates.days_ago(2) or datetime.utcnow(). However, the docs recommend against a dynamic start date:

We recommend against using dynamic values as start_date, especially datetime.now() as it can be quite confusing. The task is triggered once the period closes, and in theory an @hourly DAG would never get to an hour after now as now() moves along.

Is start date irrelevant for manually triggered dags? What is the best practice here?

Upvotes: 13

Views: 11084

Answers (3)

Andy Carlson
Andy Carlson

Reputation: 3909

I ended up just setting start_date to 1970, Jan 1st (absurdly far in the past) so that Airflow never complains that the execution date is before the start date.

Upvotes: 1

Zack
Zack

Reputation: 2466

I always try to set the start date for manually triggered DAGS as the day I first ran it so that I know when the DAG would have first been run for reference in the future.

Upvotes: 7

Simon D
Simon D

Reputation: 6279

If you have a schedule_interval=None I believe the start_date is irrelevant as airflow will not attempt to perform any back filling. Just set it to anything even if it's a dynamic one it shouldn't cause any hassle.

Upvotes: 1

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