Configurable websocket keep-alive interval

[walfie]

For websocket subscriptions, keep-alive messages are sent every 5 seconds. Is it possible to have this value be configurable? For example if I wanted to set it to 30 seconds instead, or disable it entirely.

It looks like it's hard-coded at the moment (assuming I'm looking at the right place):

graphql-engine/server/src-lib/Hasura/GraphQL/Transport/WebSocket.hs

Line 189 in b81d22f

threadDelay $ 5 * 1000 * 1000

[arpitjacob]

Hey guys any way to change this?

[abooij]

To clarify on this, the goal would be to add a configuration flag similar to --stringify-numeric-types that has to be threaded through the codebase to the relevant place (namely server/src-lib/Hasura/GraphQL/Transport/WebSocket.hs). So the steps are:

1. Add a new KeepAliveDelay newtype wrapper around the Seconds data type (the latter is defined in server/src-lib/Data/Time/Clock/Units.hs).
2. Expand the ServeOptions data type in server/src-lib/Hasura/Server/Init/Config.hs to additionally store a KeepAliveDelay.
3. Expand server/src-lib/Hasura/Server/Init.hs to support parsing a --websocket-keepalive flag, that takes a number of seconds, and stores this value in the ServeOptions object.
4. Somehow pass this value to onConn in server/src-lib/Hasura/GraphQL/Transport/WebSocket.hs. It may be desirable to pass it using MonadReader, using the same style that is used for --stringify-numeric-types which is passed in a QueryContext object. That way, one could simply add a reader constraint to onConn, and ask the compiler where this constraint needs to be satisfied, rather than having to change the number of arguments of many functions.

[KarolKalbarczyk]

I am going to give this issue a try.

[v0d1ch]

@KarolKalbarczyk I noticed some time passed since your last message and decided to try to tackle this for fun. Please close my PR if you did some work already locally, I didn't mean to steal your thunder just to explore the codebase a bit.

@abooij I think the argument passing through some of the related functions could use some love but I didn't want to go out of scope of the task. If you want this handled just create the issue and I'd be happy to help out.