router.erl

-module(router).
-author("ROJO01").
-export([start/2]).

start(N, F) ->
  Workers = spawn_workers(N, [], F),
  spawn(fun() -> round_robin_router(Workers, 0) end).

round_robin_router(Workers, Next) ->
  receive
    stop ->
      stop_workers(Workers);
    Any ->
      forward_message(Next, Workers, Any),
      round_robin_router(Workers, Next + 1)
  end.

stop_workers(Workers) ->
  io:format("Stopping workers~n"),
  lists:foreach(fun(Pid) -> exit(Pid, ok) end, Workers),
  ok.

forward_message(Next, Workers, Any) ->
  Capped = Next rem length(Workers) + 1,
  Pid = lists:nth(Capped, Workers),
  Pid ! Any.

spawn_workers(0, Workers, _) ->
  Workers;
spawn_workers(N, Workers, F) ->
  Worker = spawn(F),
  spawn_workers(N - 1, Workers ++ [Worker], F).