Determine what next execution should do for partition-driven dags

[dstandish]

Body

CLI action dag_next_execution prints next execution for logical date dags. Need to assess what to do for partition-driven and implement.

Committer

• I acknowledge that I am a maintainer/committer of the Apache Airflow project.

[shleshaG]

I understand that dag_next_execution currently works for logical-date–based DAGs, and the open question is how it should behave for partition-driven DAGs. I’m happy to take this up. Before implementing, I just wanted to confirm the expected behavior for partition-driven DAGs , for example, should the CLI:

1. compute the next available partition,
2. display a placeholder / informative message or intentionally skip output if it’s not well-defined?
   Once the intended semantics are clear, I can proceed with the implementation and open a PR accordingly.

[uranusjr]

I think the CLI should compute the partition that would be satisfied by the next scheduled run. I also think the message should be different to make clear this is showing a partition.

Not sure what you mean by not well-defined. Can you clarify? If a next partition cannot be determined, a warning should be shown similar to how we notify about non-time-based schedules.

[uranusjr]

OK I think this is what I’m going to do. To be honest I feel the current dag_next_execution output isn’t that useful to begin with. I want it to be able to show more fields. So I’m thinking

• Deprecate the current airflow dags next-execution dag-id without additional flags (we’ll maybe change it to show one of the followings in 4.0)
• Add --table to show a table of values. Probably include the logical date, data interval start and end, run_after, and the partition key.
• Add --value=<attr> to show only one of the above value.

How does this sound?

[uranusjr]

Also probably add some more fields to dag_list_dag_run to match the format.

[Lee-W]

How does this sound?

yep

dag_list_dag_run

probably add partition_key there as well? anything else you're considering?

[uranusjr]

dag_list_dag_runs also currently misses data interval fields so we might want to add them too.