A flakey worker that parses all incoming messages as integers

parser.ex

defmodule Parser do
  use GenServer
  
  def start_link() do
    GenServer.start_link(__MODULE__, :ok, [])
  end
  
  def handle_call(message, _from, state) do
    i = String.to_integer(message)
    {:reply, i, state}
  end
end