exuma.ex

defmodule Exuma do
  def doing_work(pid) do
    IO.puts("Some work, like a DB fetch")
    results = [1, 2, 42]
    send(pid, {:update_state, results})
  end
end

defmodule Exuma.StateHolderThingy do
  use GenServer

  def start_link do
    GenServer.start_link(__MODULE__, :ok)
  end

  def init(:ok) do
    Process.send_after(self(), :tick, 100)
    {:ok, nil}
  end

  def handle_info(:tick, state) do
    Process.send_after(self(), :tick, 300_000)
    schedule_work()
    {:noreply, state}
  end

  def handle_info({:update_state, results}, _state) do
    {:noreply, results)}
  end

  def schedule_work() do
    spawn &(Exuma.doing_work(self()))
  end
end