Any plan for handling "ka" (keep-alive) and ping-pong checks?

[sneko]

Hi @leszekhanusz ,

I'm wondering if there is any plan to support the keep-alive message? It comes from the server to make sure the connection is still alive, and if the client receives no KA within a specific timeout defined, it behaves as the connection was lost.

When seeing:

gql/gql/transport/websockets.py

Line 186 in d7d871f

"""Wait for the connection_ack message. Keep alive messages are ignored

and:

gql/gql/transport/websockets.py

Line 316 in d7d871f

# KeepAlive message

I understand that's not implemented, but just wondering if it's in the pipe.

Also, in the same kind of standards, Keep-Alive makes sure the client will react in case of lost connection, but on it's end the server won't know if the connection was lost (router shut down for example, or loss of connectivity, that are not proper terminations). This is usually handled for websockets by an end-to-end "ping-pong" protocol between the client and the server:

• The server sends a "ping" every X interval
• The client has to reply "pong" within a timeout defined otherwise the server considers the connection as lost (which help freeing memory and doing specific stuff like updating client status in the database...)

Is it also something on your plan? It would definitely help.

Thank you,

[sneko]

@leszekhanusz I'm almost done with implementing the keep-alive part. I will do a PR tomorrow.

I hope to start and finish tomorrow for receiving a ping from the server and sending back the pong.

Also, I'm not that familiar with Python tests and I'm not sure how to proceed (even after looking at yours). For now I'm testing with real software... After PRs I would be glad if you could take a look to see how new tests could fit the commits.

[leszekhanusz]

Hi @sneko

You are right, it could be a good idea to implement closing the connection if we don't receive a keep-alive message.
We could add a keep_alive_timeout argument to the __init__ method of WebsocketsTransportwhich is None by default (Keep Alives are just ignored as it is now) and if we don't receive a keep alive during this time raise a TimeoutError.

On the other hand, the client should never send something in response because the WebsocketsTransport transport should follow the specification

Any deviation from this protocol should be done in a custom class created by the user.

[sneko]

[EDIT]

@leszekhanusz I saw interesting work in the underlying websockets library python-websockets/websockets#928 . It already manages the ping-pong logic (responding a pong as client when receiving the ping).

I will make the PR about keep-alive with the ka messages since I still think it will help and that's another "pattern".