Define gRPC service used by Stub and Server. You should use Protobuf to to generate code instead of using this module directly.

It imports DSL functions like rpc/4 and stream/1 for defining the RPC functions easily:

defmodule Greeter.Service do
  use GRPC.Service, name: "helloworld.Greeter"

  rpc :SayHello, HelloRequest, stream(HelloReply)
end

option (google.api.http) annotations are supported for gRPC http/json transcoding. Once generated the 4th argument to rpc/4 contains the Google.Api.HttpRule option.

defmodule Greeter.Service do
  use GRPC.Service, name: "helloworld.Greeter"

  rpc(:SayHello, Helloworld.HelloRequest, Helloworld.HelloReply, %{
    http: %{
      type: Google.Api.PbExtension,
      value: %Google.Api.HttpRule{
        __unknown_fields__: [],
        additional_bindings: [],
        body: "",
        pattern: {:get, "/v1/greeter/{name}"},
        response_body: "",
        selector: ""
      }
    }
  })
end