task.ex

defmodule Ploy.Task do
  use GenEvent

  def start do
    result = {:ok, pid} = GenEvent.start_link([])
    GenEvent.add_handler(pid, Ploy.Task, [])
    result
  end

  def run(pid) do
    GenEvent.notify(pid, :run)
  end

  def handle_event(:run, state) do
    Port.open({:spawn, "ruby sup.rb"}, [:stderr_to_stdout, :binary, :exit_status])

    {:ok, state}
  end

  def handle_info({_port, {:data, data}}, state) do
    IO.puts(data)
    {:ok, state}
  end

  def handle_info({_port, {:exit_status, 0}}, state) do
    IO.puts("done")
    {:ok, state}
  end

  def handle_info({_port, {:exit_status, status}}, _state) do
    raise "exited with status: #{status}"
  end
end