Maximum queued runs for an individual DAG

[Pants Pants <gp...@gmail.com>]

Hello there,

I have a DAG which is only ever triggered externally, via POSTing against
the http://airflow-server/api/experimental/dags/my_triggered_dag/dag_runs
url.

I have max_active_runs=1 in the DAG in order to enforce that there's only
one run at a time. If a run is currently happening, subsequent automated
requests to the triggered dag URL end up getting queued up for execution
after the already running job completes.

Although the work is idempotent, it would be inefficient to do subsequent
runs that have queued up when the first run completes the work needed. It's
also possible that an error could occur where the dag is triggered hundreds
of times in a short time window. I'd rather these subsequent requests were
either dropped or ignored.

Is there a way to limit the number of queued (to-be-ran) dag runs for a
specific dag? As in, the scheduler simply doesn't attempt to queue more of
a given dags runs beyond a certain point?

Thanks!