F5 BIG-IP can be programmed in Tcl. While it is a programming language, I have only seen it programmed by non-developers. With copy paste code, repeated string constants all over the place and no unit tests.
I agree that load balancer a do need the expressiveness of programming languages, but ideally that would only be with some typing and ability to easily un it test.
Yes! And a good surface API, OpenResty (nginx + lua) is reasonably powerful but you're really limited based on the events they give you.
I'm really hopeful about deno (https://github.com/denoland/deno) for this. TypeScript is nice, the deno TCP perf is good, all it needs is some good proxy libraries.
I agree that load balancer a do need the expressiveness of programming languages, but ideally that would only be with some typing and ability to easily un it test.