Async task

gistfile1.ex

defmodule Alchemy.Time do
  @author "Iuri L. Machado <[email protected]>"
  @copyright "2015 .Fix."
  @license "BSD"

  use GenServer
  require Logger

  @moduledoc """
    RFC 1123 Time compatible. It caches time on an ets table that is updated
    every second and all time API calls come from the cached time, so it
    provides very fast date/time computations. Based on cowboy.
  """

  def start_link do
    GenServer.start_link __MODULE__, []
  end

  @doc """
    Starts the time process and sets up the ets table.
  """
  def init _args do
    Logger.info "Initializing Time."
    :ets.new :time_cache, [:set, :public, :named_table,
                          {:read_concurrency, true}]
    utc = :erlang.universaltime
    :ets.insert :time_cache, {:time, utc}
    Task.async fn ->
      :erlang.universaltime |> update_internal_time
    end
    # spawn(fn ->
    #   :erlang.universaltime |> update_internal_time
    # end)
    {:ok, "Time Initialization Done"}
  end

  @doc """
    Gets current time.
  """
  def get_rfc1123 do
    GenServer.call __MODULE__, :now
  end

  def handle_call :now do
    time = :ets.lookup :time_cache, :time
    {:reply, time}
  end

  def handle_cast {:update_time, "start"} do
    :erlang.universaltime |> update_internal_time
    {:noreply, :ok}
  end

  defp update_internal_time utc do    # Updates the internal time on ets.
    :timer.sleep 1000
    Logger.info "#{__MODULE__}: Updating internal time."
    :ets.insert :time_cache, {:time, utc}
    :erlang.universaltime |> update_internal_time
  end

  defp day num do
    case num do
      1 -> "Sun"
      2 -> "Mon"
      3 -> "Tue"
      4 -> "Wen"
      5 -> "Thu"
      6 -> "Fri"
      7 -> "Sat"
    end
  end

end