Bug report

Bug description:

When writing an asyncio based service, you basically have this sequence:

1. Create an event loop
2. Register a SIGTERM handler
3. Start your server
4. loop.run_forever()
5. SIGTERM causes a loop.stop()
6. Close the server
7. Close event loop

If there are any connections active at this point, then they don't get discarded until interpreter shutdown, with the result that you get a bunch of ResourceWarnings (and cleanup code might not run).

It would be very useful if there was a Server.close_clients() or something like that. Even a Server.all_transports() would be useful, as then you could do something similar as when doing a Task.cancel() on what you get from loop.all_tasks().

We could poke at Server._transports, but that is something internal that might change in the future.

There is Server.wait_closed(), but that hangs until all clients have gracefully disconnected. It doesn't help us when we want to shut down the service now.

CPython versions tested on:

3.12

Operating systems tested on:

Linux

Linked PRs

• gh-113538: Don't crash in stream reader protocol callback when task is cancelled #113690
• [3.12] gh-113538: Don't error in stream reader protocol callback when task is cancelled (GH-113690) #113713
• [3.11] gh-113538: Don't error in stream reader protocol callback when task is cancelled (GH-113690) #113714
• gh-113538: Allow client connections to be closed #114432
• gh-113538: Revert "gh-113538: Add asycio.Server.{close,abort}_clients (#114432)" #116632
• gh-113538: Allow client connections to be closed #116784