Awesome that we get the health check for free! I assume we'll need to implement something on the client for that to work, yes? The Tunnelbroker client in keyserver currently uses the ws library for Node.js

In D9158#269711, @ashoat wrote:

Awesome that we get the health check for free! I assume we'll need to implement something on the client for that to work, yes? The Tunnelbroker client in keyserver currently uses the ws library for Node.js

We tested that with @kamil and fortunately no client changes are needed. The client library is already handling upgrade requests properly.

I'm asking specifically about the health check. It's my understanding that the WebSocket protocol does not have any built-in health checks. Given we're using the Node.js ws library directly on the keyserver side, it seems like we'll either need to switch to using a compatible (Rust-based?) client, OR we'll need to do some additional work on the keyserver to implement this health check. Is that accurate?

This health check is only needed by AWS to check if the instance endpoint is healthy. It's more related to ENG-4470.

It's my understanding that the WebSocket protocol does not have any built-in health checks.

That's right. The check endpoint is pure HTTP, it has nothing in common with WebSocket, except port number. If you really want to check health on client side, you can simply fetch('http://tunnelbroker.host:websocket_port/health').

Or, if you mean a kind of ping-pong heartbeat, this is unrelated to this particular health check, I see there's a task for it (ENG-4313) - that can be implemented e.g. as a separate tunnelbroker message type and sent repeatedly after the connection (websocket session) is already established.

Ah sorry, I misunderstood!