A gRPC server which handles requests by calling user-defined functions.

You should pass a GRPC.Service in when use the module:

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

  rpc :SayHello, Request, Reply
  rpc :SayGoodbye, stream(Request), stream(Reply)
end

defmodule Greeter.Server do
  use GRPC.Server, service: Greeter.Service

  def say_hello(request, _stream) do
    Reply.new(message: "Hello")
  end

  def say_goodbye(request_enum, stream) do
    requests = Enum.map request_enum, &(&1)
    GRPC.Server.send_reply(stream, reply1)
    GRPC.Server.send_reply(stream, reply2)
  end
end

Your functions should accept a client request and a GRPC.Server.Stream. The request will be a Enumerable.t(created by Elixir's Stream) of requests if it's streaming. If a reply is streaming, you need to call send_reply/2 to send replies one by one instead of returning reply in the end.