[DISCUSS] Dubbo support Google Protobuf generic reference#PR:3825

[vio-lin]

support Google Pb generic invocation

purpos

Currently, Generic Reference cannot support Google Protobuf. With bride usage of Google PB, we are going to support it via Generic Reference.

problem

Google protobuf entity generated by builder. It can't be created by generic filter.

Util Used

There are some project can convert json and google protobuf entity java-protobuf-util .

how to invoke service

1. build serviceDefinition metadata of protobuf service. We can build typeDefinition by parsing methods of Innner Builder of entity.
2. client generates json string by service metadata.
3. modify generic filter in provider to support serialize json to Pb object.
4. add ProtobufUtil.class to serialize /deserialize Google Protobuf Object

feedback wanted

To support Google PB Testing, GenericFilter is part of my change, also Service Metadata have to support that. I want to know if it is gracefull enough to solve this problem.