What's the best pattern for a pubsub event listener? GenServer seems like the wrong choice

Questions & Help Questions
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This seems ok, because at least it’s async to the user liking the message, but now all “notification_events” (let’s say those are :liked_message and :message_reply) are handled sequentially.

This is a fact, but whether it’s a problem or not depends on your specific use case.

For instance, it provides a free guarantee that notifications are handled in precisely the order transmitted.

  def handle_info({:liked_message, msg}, state) do
    Task.start(__MODULE__, :create_notification_here, [msg])
    {:noreply, state}
  end

Be careful with patterns like this - if a LOT of messages come in at once, there’s no limit on how many processes this tries to start. Consider using something like :poolboy to get parallel workers with bounded resource consumption.