Close connections gracefully.

[Lukasa]

We should send GoAway frames when we close a connection.

[jdecuyper]

Hi @Lukasa!

Spec says: Endpoints SHOULD send a GOAWAY frame when ending a connection, providing that circumstances permit it.

So when shutting down gracefully we need to call close on all streams and then send a final GoAway frame on the connection control stream, something like:

# Close all streams
for stream in list(self.streams.values()):
   print("Closing stream with id %d" % stream.stream_id)
   stream.close()

# Send GoAway frame to the server
   self._send_cb(GoAwayFrame(0), True)

I think we should also close the stream for connection control with id 0, but I'm not sure yet where it is.

On a related matter, the spec also says An endpoint that receives an unexpected stream identifier MUST respond with a connection error (Section 5.4.1) of type PROTOCOL_ERROR. I don't think we are validating if the stream identifier actually exists or not on the client side. Code looks as follow right now:

self.streams[frame.stream_id].receive_frame(frame)

I guess we should validate first if this stream_id exists inside the streams collection, right?

[Lukasa]

I think we should also close the stream for connection control with id 0, but I'm not sure yet where it is.

Stream zero always exists, and there is no need to explicitly close it.

I guess we should validate first if this stream_id exists inside the streams collection, right?

A try...except block would be better style, but yes. =)

So when shutting down gracefully we need to call close on all streams and then send a final GoAway frame on the connection control stream

Sounds like a good idea to me!