Add a calendar field to choose the execution date of the DAG when triggering it

[JPonte]

Currently the Trigger DAG always triggers a DAG run with now() as execution date. Since execution_date is a parameter of the dagrun the same way conf is, it makes sense to be able to change it in the UI as well.

[bbovenzi]

Great idea! But it looks like test_views_trigger_dag.py is failing

[JPonte]

@bbovenzi I fixed the failing test but the CI still fails for mssql but it doesn't really say where and I can't even seem to run it on breeze.

[JPonte]

Thanks @mrbaguvix

[bbovenzi]

Looking good! Past and future dates work great.

[bbovenzi]

@ashb or @ryanahamilton Can we restart the CI here?

[ashb]

Restarted.

[ashb]

    ERROR: HTTP error 404 while getting https://github.com/apache/airflow/archive/master.tar.gz#egg=apache-airflow[devel_ci]

This PR needs rebasing on to get the master->main rename

[bbovenzi]

@JPonte could you resolve the conflicts and hopefully we can get this merged soon.

[JPonte]

@bbovenzi I fixed the conflicts with main but the checks still timeout on the "Wait for CI images" job.

[ashb]

Could you expand the tests to see what the behaviour is when an invalid date is submitted please?

Something like: it should still be a 200, but there should be a error message somewhere.

[uranusjr]

Thanks!

[github-actions]

The PR is likely OK to be merged with just subset of tests for default Python and Database versions without running the full matrix of tests, because it does not modify the core of Airflow. If the committers decide that the full tests matrix is needed, they will add the label 'full tests needed'. Then you should rebase to the latest main or amend the last commit of the PR, and push it with --force-with-lease.