Support for graceful shutdown / DB conn. termination?

[wh4everest]

The PG pool opens connections towards the database. When the app is killed, or when a script finishes, these aren't gracefully terminated and we get these messages:

db_1          | 2019-03-12 12:55:42.030 UTC [9527] xxx@xxx LOG:  could not receive data from client: Connection reset by peer
db_1          | 2019-03-12 12:55:42.030 UTC [9528] xxx@xxx LOG:  could not receive data from client: Connection reset by peer
db_1          | 2019-03-12 12:55:42.033 UTC [9529] xxx@xxx LOG:  could not receive data from client: Connection reset by peer

This isn't causing functional problems, but it's not ideal either.

There are other examples where we want to react to the termination of the program -- maybe stop accepting new requests and wait for active ones to finish?

What would be the correct way for the framework to support graceful shutdowns?

[spion-h4]

app.getSingleton(AppEvents).onAppShutdown(callback); event