Here is a Go operator based the on Kubebuilder framework; for those who can follow Kubebuilder too simple example and cannot follow the next too complex one.
Update (Aug 2018)- There is a better option than this ; there is a GRPC-Web project from Google; Please check this first https://medium.com/@alexcpn/interface-grpc-with-web-using-grpc-web-and-envoy-possibly-the-best-way-forward-3ae9671af67