Switch to gRPC API

[peburrows]

Once River is ready, we'll use that as the basis for our gRPC support.

[mitcheaton1]

Is diplomat currently using grpc? Or is it making requests over http?

[peburrows]

Diplomat currently talks to Google over http/1.1. My progress on River (my http/2 client) has stalled a bit because of lack of time, but my hope is to pick it back up again soon. Once River is finished, switching Diplomat to full grpc should be pretty straightforward since it already uses the protobuf APIs.

[lpil]

There are a few existing HTTP2 clients in the Erlang ecosystem, could we possibly use one of those?

https://github.com/ninenines/gun
https://github.com/CrowdHailer/Ace

[peburrows]

Most recently, my plan has shifted to use https://github.com/tony612/grpc-elixir for the grpc piece. Under the hood, it currently uses chatterbox, but that's not really of consequence to Diplomat.