How to approach simultaneous description and generation of an HTTP and gRPC and however many operations contracts?

[artsiommiksiuk]

If I were to emmit and implement simultaneously functionally equivalent contracts in HTTP and gRPC how would I declare and emit them in a non conflicting way?

E.g, simplest protocol independent definition of some operation.

op createEntity(id: string): { id: number };
op get(id: string): Entity | undefined;

For Http case definition will look like this:

@post
op createEntity(@path id: string): OkResponse & { id: number };
@get
op get(@path id: string): (OkResponse & Entity) | NotFoundResponse;

For gRPC case it might look like:

@rpc
op createEntity(@field(0) id: string): { id: number };
@rpc
op get(@field(0) id: string): Entity;

It is clear that two definitions are not compatible and I don't know clear ways of separating them for two emitters, except having two different definitions, which kinda sucks, as I was thinking that typespec can achieve common ground and declare once and emit to multiple targets.

So, how would one achieve that with TypeSpec?

[artsiommiksiuk]

Hm. Look at this, my example is not actually fully equivalent for the get, because common implementation declaring two possibilities, entity found and entity not found, which I'm basically ommiting in gRPC case.

@rpc
op createEntity(@field(0) id: string): grpcOk & { id: number };
@rpc
op get(@field(0) id: string): (grpcOk & Entity) | grpcNotFound;

Assuming there are some equivalent ok and notFound structures to mix in, though structurally different, still is not clear how to then proceed? Filter out by decorators, like with json-schema?

Then merged definition might be

@post
@rpc
op createEntity(@field(0) @path id: string): OkResponse & grpcOk & { id: number };
@get
@rpc
op get(@field(0) @path id: string): (OkResponse & grpcOk & Entity) | (NotFoundResponse & grpcNotFound);