http middleware for converting connect http request to grpc request

[rauanmayemir]

I'm building a gRPC-server as a mux handler that is supposed to chain via http middlewares and then ultimately apply grpcServer.ServeHTTP(writer, req).

What is a proper way to set up http middleware for connect converter that does not know anything about grpc/protobuf types (an isolated http handler func)?

Basically, I want to transiently convert inbound http request into a grpc-compliant http request with all appropriate headers, etc.
Docs only provide examples where I'm building a connectrpc server which is not my case.

Seeing the envoy http filter I am sure this is possible as envoy.filters.http.connect_grpc_bridge has no knowledge of protobuf types.

[rauanmayemir]

Jus discovered https://github.com/connectrpc/vanguard-go, but IIUIC it needs to wrap the grpcServer and what I need should only work with http.Request

[rauanmayemir]

Vanguard generally looks like a perfect tool for the job. 😍

[timostamm]

Hey Rauan, it is correct that it's possible to convert a Connect request to a gRPC request without knowledge of the Protobuf schema - as long as both use the same codec (JSON or Protobuf binary).

This is out of scope for connect-go, but Vanguard supports this translation (and a bit more) and should do what you want - vanguard.Transcoder is a http.Handler. If you have any questions or feature request, it's best to open an issue in the Vanguard repository.

[rauanmayemir]

Thanks you, will start experimenting with vanguard! 🙏