google.protobuf.Empty import not generating properly

[PranavSathy]

Hi All, I have a very simple .proto file:

syntax = "proto3";
package service;

import "google/api/annotations.proto";
import "google/protobuf/empty.proto";

service TestService {
    rpc PrintAuth(google.protobuf.Empty) returns (google.protobuf.Empty) {
        option (google.api.http) = {
            get: "/client/print"
        };
    }
}

And I am compiling it using the two commands:

protoc -I/usr/local/include -I. \
        -I$GOPATH/src \
        -I$GOPATH/src/github.com/grpc-ecosystem/grpc-gateway/third_party/googleapis \
        --go_out=Mgoogle/api/annotations.proto=github.com/grpc-ecosystem/grpc-gateway/third_party/googleapis/google/api,Mgoogle/protobuf/empty.proto=github.com/golang/protobuf/ptypes/empty,plugins=grpc:. \
        service/test_service.proto

protoc -I/usr/local/include -I. \
        -I$GOPATH/src \
        -I$GOPATH/src/github.com/grpc-ecosystem/grpc-gateway/third_party/googleapis \
        -I$GOPATH/src/github.com/golang/protobuf/ptypes/empty \
        --grpc-gateway_out=logtostderr=true,Mgoogle/protobuf/empty.proto=github.com/golang/protobuf/ptypes/empty:. \
        service/test_service.proto

However, I get this weird issue in my "test_service.pb.gw.go" file, where it imports github.com/golang/protobuf/ptypes/empty but the handler produces the following lines of code:

func request_TestService_PrintAuth_0(ctx context.Context, marshaler runtime.Marshaler, client TestServiceClient, req *http.Request, pathParams map[string]string) (proto.Message, runtime.ServerMetadata, error) {
    var protoReq google_protobuf.Empty
    var metadata runtime.ServerMetadata

    msg, err := client.PrintAuth(ctx, &protoReq, grpc.Header(&metadata.HeaderMD), grpc.Trailer(&metadata.TrailerMD))
    return msg, metadata, err

}

The issue there is is that google_protobuf.Empty should be empty.Empty. How can I fix this, is there something in particular I am doing wrong?

[yugui]

Can't reproduce. This is what I got from the steps you had shown.

func request_TestService_PrintAuth_0(ctx context.Context, marshaler runtime.Marshaler, client TestServiceClient, req *http.Request, pathParams map[string]string) (proto.Message, runtime.ServerMetadata, error) {
        var protoReq empty.Empty
        var metadata runtime.ServerMetadata

        msg, err := client.PrintAuth(ctx, &protoReq, grpc.Header(&metadata.HeaderMD), grpc.Trailer(&metadata.TrailerMD))
        return msg, metadata, err

}

[PranavSathy]

Could it be an issue with my libprotoc (v3.0.0)? I made sure to run go get -u on all the major packages (including github.com/golang/protobuf).

[yugui]

@PranavSathy I don't think so. But it might be worth to reinstall the latest stable version of protoc just in case.