A Rust macros use case: Tightly-coupled API definitions for a client and server (opens in new tab)

I’m working on a Kubernetes operator and an API server for it to interface with. Both of these are crates in the same Rust workspace. The motivation for this was that I wanted to define all of the types used by the two services in one place, and keep the services tightly-coupled. When writing the operator, I wrote a protocol to define the HTTP requests the operator sends to the server: