Debug Logging for Rails Autoloading

autoload-logging.rb

# Include this in the config/application.rb of your rails application

require 'colorize'
ActiveSupport::Dependencies.singleton_class.prepend(Module.new do
  def load_missing_constant(*args)
    arg_str = args.map(&:to_s).select { |arg| arg != 'Object' }.join('::').green
    start   = Time.now
    result  = nil

    mv_with_indent do |indent|
      indent_space = ' ' * indent * 4
      puts "AUTOLOADING START: #{indent_space} +-> #{arg_str}"

      begin
        result = super
        puts "AUTOLOADING DONE : #{indent_space} +-> #{arg_str} -- #{mv_duration_string(start)}"
      rescue StandardError => e
        puts "AUTOLOADING FAIL : #{indent_space} +-> #{arg_str} #{e} -- #{mv_duration_string(start)}"
        raise
      end
    end

    result
  end

  def mv_with_indent
    Thread.current[:_auto_reload_indent] ||= 0
    Thread.current[:_auto_reload_indent] += 1
    yield Thread.current[:_auto_reload_indent]
  ensure
    Thread.current[:_auto_reload_indent] -= 1
  end

  def mv_duration_string(start, finish: Time.now)
    duration = (finish - start) * 1000.0
    duration_str = "#{duration.round(2)}ms"
    if duration > 10
      duration_str.red
    elsif duration > 1
      duration_str.yellow
    else
      duration_str
    end
  end
end)