Running mix tasks in production

Question

I have a number of tasks and jobs that I would like to be able to execute manually on a production elixir application. Currently, I have been performing them by running the code inside the remote_console. I Attempted to run them by using /bin/my_app command MyModule my_func, but I get errors about resources being used by another Erlang node.

I would prefer to use the /bin/my_app command MyModule my_func style so I can run the bash scripts using ssh.

What's is the recommended way to run remote tasks on Elixir application?

Answer 1

Running mix tasks in production is not possible, since mix is not part of the application release.

However, it is obviously possible to include any code in the final application release, so you can add the code that would run migrations on app start.

Documentation for Ecto.Migrator module contains a sample migration runner:

defmodule MyApp.Release do
  @app :my_app

  def migrate do
    for repo <- repos() do
      {:ok, _, _} = Ecto.Migrator.with_repo(repo, &Ecto.Migrator.run(&1, :up, all: true))
    end
  end

  def rollback(repo, version) do
    {:ok, _, _} = Ecto.Migrator.with_repo(repo, &Ecto.Migrator.run(&1, :down, to: version))
  end

  defp repos do
    Application.load(@app)
    Application.fetch_env!(@app, :ecto_repos)
  end
end

Then, a command to run migration can be included as part of the release start up:

bin/my_app eval "MyApp.Release.migrate"