module ControllerMethods
  def self.included(base)
    base.extend(ClassMethods)
  end

  module ClassMethods
    def class_get_config(key)
      -> { puts "#{key} #{self}" }
    end
  end

  def public_instance_get_config(key)
    -> { puts "#{key} #{self}" }
  end

  private

  def private_instance_get_config(key)
    -> { puts "#{key} #{self}" }
  end

  def apply_config(key)
    self.class.class_get_config(key).call
    self.public_instance_get_config(key).call
    self.instance_exec &private_instance_get_config(key)
  end
end

class MyController
  include ControllerMethods

  def test
    apply_config :param
  end
end

MyController.new.test