memEx/lib/lokal/release.ex

defmodule Lokal.Release do
  @moduledoc """
  Contains mix tasks that can used in generated releases
  """

  @app :lokal

  def rollback(repo, version) do
    load_app()

    {:ok, _fun_return, _apps} =
      Ecto.Migrator.with_repo(repo, &Ecto.Migrator.run(&1, :down, to: version))
  end

  defp load_app do
    Application.load(@app)
  end

  def migrate do
    load_app()

    for repo <- Application.fetch_env!(@app, :ecto_repos) do
      {:ok, _fun_return, _apps} =
        Ecto.Migrator.with_repo(repo, &Ecto.Migrator.run(&1, :up, all: true))
    end
  end
end