Make sure killing `meltano ui` reaps Airflow
Right now, there is chance that Airflow will still be running after
meltano ui has been terminated, which causes subsequent
meltano ui to not properly start Airflow.
Basically the issue stems from the fact that the Airflow webserver ports will be unavailable.
I had the impression that spawning
subprocesses would automatically forward any SIGNAL the main process received, but that might be wrong.
Implement proper signal handling in
meltano ui to make sure we kill any running Airflow instance
We could also add a check for the ports when we start
meltano ui, so the user have an idea what is going on.
Ports to check:
5000: meltano ui
5010: airflow webserver