This is a really neat demo, but there's a few limitations that are glaring issues for a chat server or most scenarios I can think of that I would want to use websockets. As many have mentioned, the 250 connection limit per instance is crazy. You can get 200x that many easily on a single 1 VCPU box.

The second problem is that really the demo has just kicked your scaling problem over to redis. The demo isn't doing anything actually interesting, redis is doing all the work. The reality is that one of the best parts of Cloud Run over something like serverless functions is that you can have state in your server. You don't need redis at all if you are doing the same demo in Kubernetes without Cloud Run, since it's pretty easy to use channels in golang to do the same thing. However, in order for you to really make that work, you need some way to at the very least route the traffic consistently so that people watching the same resource get routed to the same server, or to be able to have cross node communication.

So this is a great start, but a little work to go before many people would be able to switch over to something like this due.