I have something like this. There is probably a much better way of doing it.

defmodule Learnp.LayoutView do
  use Learnp.Web, :view
  import Learnp.Router.Helpers

  def show_notification(conn) do
    conn
    |> get_flash
    |> flash_message
  end

  def flash_message(%{"info" => message}) do
    render "components/_notification.html", class: "primary", message: message
  end

  def flash_message(%{"error" => message}) do
    render "components/_notification.html", class: "danger", message: message
  end

  def flash_message(_), do: nil

end

And on my templates I can call it with <%= show_notification(@conn)%> and it will render the partial web/templates/layout/components/_notification.html.eex.

It’s just some HTML with Bootstrap markup

<div class="callout <%= @class %>" data-closable>
  <button class="close-button" aria-label="Fechar alerta" type="button" data-close>
    <span aria-hidden="true">&times;</span>
  </button>
     <%= @message %>
</div>