Custom logger on Sinatra

app.rb

class App < Sinatra::Base
  configure do
    set :logger_level, :warn
    set :logger_log_file, File.join(root, 'log', "#{environment}.log")
  end

  configure :development do
    set :logger_level, :debug
  end

  configure :prodcution do
    set :logger_level, :info
  end

  configure do
    logger_log_file.tap do |file|
      fd = File.open(file, 'ab')
      fd.sync = true
      logger = ActiveSupport::Logger.new(fd)
      logger.level = ActiveSupport::Logger.const_get(logger_level.to_s.upcase)
      ActiveSupport.on_load(:active_record) { self.logger ||= logger }
      set :logger, logger
    end
  end

  helpers do
    def logger
      self.class.logger
    end
  end
  
  get '/hello' do
    logger.info('hello')
    'hello'
  end
end