If you’re like me, you probably spend a lot of time in the Rails console interrogating objects and fiddling with data to debug your application. As I work on a project, I end up with a growing list of useful snippets to lightly modify and paste into the console to complete common tasks.

A tweet by Sebastien Auriault showed me that you can define methods that will be directly accessible in your Rails console without necessarily affecting your production code.

How?

Depending on where you want these methods to be available, you can add the following code to config/initializers/console_methods.rb or to lib/console_methods.rb and require the file in the appropriate environment(s).

module Rails::ConsoleMethods
  # Grab your favourite test user without having
  # having to remember or type much about them
  def test_user
    User.find_by(email: 'my_test_user@example.com')
  end
  
  # Reset your test user back to some baseline
  def reset_test_user
    test_user.update(
      status: :pending,
      registration_confirmed_at: nil,
      current_balance: 0
    )
  end
  
  # Quickly benchmark some code
  def bm(&block)
    puts "Running a quick benchmark:"
    puts Benchmark.measure(&block)
  end
  
  # Clear all of your queued Sidekiq jobs
  def nuke_sidekiq
    Sidekiq::Queue.new.clear
  end
end

Why?

None of these examples are breathtaking. Why bother at all?

  1. Sharing knowledge. A shared, well-documented set of custom commands allows the entire team to take advantage of these little time-savers.
  2. Safety. If you mistype reset_test_user you’re a lot less likely to encounter unexpected behaviour than if you attempt to manually update records by hand.
  3. Repeatability. Encouraging developers to use the existing methods for common tasks makes it easier to add appropriate guard rails and logging, and ensures that the action is performed in the same way every time.

Why not?

Consider the following example which puts an app into maintenance mode, logging users out and preventing further access.

module Rails::ConsoleMethods
  def enable_maintenance_mode!
    authenticate_developer
    log_action(:enabled_maintenance_mode)
    
    MaintenanceMode.enable!
  end
end

This is a good idea on the surface, but there’s nothing to prevent a developer from bypassing the authentication and logging entirely and calling MaintenanceMode.enable! directly on the console. As cool as this technique is, if security and auditing is a priority, it’s not sufficient to trust developers to use the approved methods.

If these issues are relevant to your use case, you’d be better off looking at this technique in conjunction with something like Basecamp’s console1984 which is a more robust attempt to provide secure authentication and logging in Rails console sessions.