AIP-38 Add validation to Run Backfill modal

[bbovenzi]

Body

On the Run Backfill modal. We should add a few more checks before allowiing a user to submit.

• Max Active Runs: Form should have a min of 1 and a max of dag.max_active_runs. We should default the user to 1
• Date range from and to should both be valid dates
• One reprocessor behavior should be selected. We should default to "Missing Runs"

Committer

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

[vatsrahul1001]

@bbovenzi currently we only show backfill count from dry run. It would be good if we can show dates as well.

[aritra24]

@vatsrahul1001 we already have the date being selected in the form? So is there a need to re-display the same value?

[bbovenzi]

I'm also confused. @vatsrahul1001 could you explain more?

[vatsrahul1001]

@bbovenzi currently from dry_run endpoint we are getting count I think here right? Would it make sense to show the exact dates on which backfill will be executed.

[bbovenzi]

Oh I see, like showing a table of the runs like we do with Clearing a dag run?