Option for automatic graceful shutdown

Would it be possible to publicly expose the self._invocations dictionary (https://github.com/crossbario/autobahn-python/blob/2e94d12c176eb34e74c788ceb4ada0b7bef916f6/autobahn/wamp/protocol.py#L356) in the WAMP protocol? For background, we want to be able to wait on all pending incoming requests to complete when we are shutting down a WAMP session. Alternatively, if there is a way to guarantee that the incoming requests are completed before disconnecting, that would work too.

[asgoel]

@oberstet wouldn’t we want to do 2 before 1?

[oberstet]

Here is a possible design I think would cover the use case.

Add a new option to leave:

def leave(self, reason=None, message=None, graceful_leave=0):

If graceful_leave>0, then:

1. wait at most graceful_leave seconds for any outstanding calls, invocations and acknowledged publications to finish
2. unsubscribe and unregister any subscriptions and registrations
3. send wamp.message.Goodbye

If graceful_leave==0, then send wamp.message.Goodbye immediately

Note: according to the WAMP protocol, a peer must not send anything after sending a GOODBYE message, and must respond by replying GOODBYE after receiving such message (it must not send anything else)