Others pointed plenty of arguments, but the ones I find most compelling (not necessarily useful in this context) are:
- you can serve any number of disjoint websocket services via same port via HTTP routing
- this also means you can do TLS termination in one place, so downstream websocket service doesn't have to deal with the nitty-gritty of certificates.
Sure, it adds a hop compared to socket passing, and there are ways to get similar fanout with TCP with a custom protocol. But you need to add this to every stack that interacting components use, while websockets libraries exist for most languages that are likely to be used in such an endeavor.
- you can serve any number of disjoint websocket services via same port via HTTP routing - this also means you can do TLS termination in one place, so downstream websocket service doesn't have to deal with the nitty-gritty of certificates.
Sure, it adds a hop compared to socket passing, and there are ways to get similar fanout with TCP with a custom protocol. But you need to add this to every stack that interacting components use, while websockets libraries exist for most languages that are likely to be used in such an endeavor.