How can I schedule code to run every few hours in Elixir or Phoenix framework?

elixir phoenix-framework
NoDisplayName picture NoDisplayName · Aug 19, 2015 · Viewed 26.8k times · Source

So let's say I want to send a bunch of emails or recreate sitemap or whatever every 4 hours, how would I do that in Phoenix or just with Elixir?

Answer

José Valim picture José Valim · Aug 19, 2015

There is a simple alternative that does not require any external dependencies:

defmodule MyApp.Periodically do
  use GenServer

  def start_link do
    GenServer.start_link(__MODULE__, %{})
  end

  def init(state) do
    schedule_work() # Schedule work to be performed at some point
    {:ok, state}
  end

  def handle_info(:work, state) do
    # Do the work you desire here
    schedule_work() # Reschedule once more
    {:noreply, state}
  end

  defp schedule_work() do
    Process.send_after(self(), :work, 2 * 60 * 60 * 1000) # In 2 hours
  end
end

Now in your supervision tree:

worker(MyApp.Periodically, [])

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