View Source mix eval (Mix v1.18.0)

Evaluates the given code within a configured application.

$ mix eval "IO.puts(1 + 2)"

The given code is evaluated after the current application has been configured but without loading or starting them (some applications may be loaded as part of booting but that's not guaranteed). See mix run for running your application and scripts within a started application.

This task is designed to mirror the bin/my_app eval command in releases. It is typically used to invoke functions already defined within your application. For example, you may have a module such as:

defmodule MyApp.ReleaseTasks do
  def migrate_database do
    Application.load(:my_app)
    ...
  end
end

Once defined, you can invoke this function either via mix eval or via bin/my_app eval inside a release as follows:

$ mix eval MyApp.ReleaseTasks.migrate_database
$ bin/my_app eval MyApp.ReleaseTasks.migrate_database

As you can see, the current application has to be either explicitly loaded or started in your tasks, either by calling Application.load/1 or Application.ensure_all_started/1. This gives you full control over the application booting life cycle. For more information, see the Application module.

This task is automatically re-enabled, so it can be called multiple times with different arguments.

Command-line options

  • --no-archives-check - does not check archives
  • --no-compile - does not compile even if files require compilation
  • --no-deps-check - does not check dependencies
  • --no-elixir-version-check - does not check the Elixir version from mix.exs
  • --no-mix-exs - allows the command to run even if there is no mix.exs