golang protobuf remove omitempty tag from generated json tags

Question

I am using google grpc with a json proxy. for some reason i need to remove the omitempty tags from the struct generated in the *.pb.go files.

if i have a proto message like this

message Status {
  int32 code = 1;
  string message = 2;
}

The generated struct looks like this

type Status struct {
  Code int32 `protobuf:"varint,1,opt,name=code" json:"code,omitempty"`
  Message string `protobuf:"bytes,2,opt,name=message" json:"message,omitempty"`
}

But My need is to remove the omitempty tag from the generated structs. How can i do this?

Answer 1

If you are using grpc-gateway and you need the default values to be present during json marshaling, you may consider to add the following option when creating your servemux

    gwmux := runtime.NewServeMux(runtime.WithMarshalerOption(runtime.MIMEWildcard, &runtime.JSONPb{OrigName: true, EmitDefaults: true}))

Outside of grpc-gateway, if you want to marshal your protocul buffer message, use github.com/golang/protobuf/jsonpb package instead of encoding/json

func sendProtoMessage(resp proto.Message, w http.ResponseWriter) {
    w.Header().Set("Content-Type", "application/json; charset=utf-8")
    m := jsonpb.Marshaler{EmitDefaults: true}
    m.Marshal(w, resp) // You should check for errors here
}