Derive macros to create protobuf schema from Rust types

[xgreenx]

I couldn't find derive macro(or any kind of macros) to generate protobuf schema from the Rust type.

Is it implemented somewhere? If not, is there a reason(maybe some limitations) why is was not done yet?

[ArtifyCZ]

Yeah, this could be pretty nice and useful! 🤩

Would it be too much of work to make it a function on the Message trait returning some kind of representation of the schema of the type the Message trait is implemented for. I'd guess it wouldn't be so difficult to implement some kind of schema description of a message type, though it couldn't really describe "the schema as a whole", I think. I'd say it might be possible to implement similar way the Display trait works—to be specific, it could be done through some kind of "Protobuf schema builder" (Protobuf type description builder, or whatever, hope you get the idea) with every single type we want to include adding its own schema/message description into the builder. 🤔

Anyway, I hope that this comment will be found by anyone useful! 😅

Just have a question though, is actual server reflection implemented for Tonic or some other gRPC implementation based on the Prost implementation of Protobuf? I mean, I see how the Protobuf schema description building impl (as I described earlier in this comment) would allow the server reflection to be done fully and automatically.

[4r33x]

https://github.com/4r33x/proto-rs

But its not fully polished yet, main branch should be pretty stable for proto_dump and proto_rpc macros

proto_message and proto_rpc do internal conversions between macro-generated prost and native types, which is not ideal; look into proto_ext branch if you need more performance