golang protobuf remove omitempty tag from generated json tags

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 protocol buffer message, use google.golang.org/protobuf/encoding/protojson (*) package instead of encoding/json

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

(*) google.golang.org/protobuf replaces the now deprecated github.com/golang/protobuf and its jsonpb package.