pretty_log_formatting.rb

class ActiveSupport::BufferedLogger
  def formatter=(formatter)
    @log.formatter = formatter
  end
end

class Formatter
  SEVERITY_TO_TAG_MAP     = {'DEBUG'=>'meh', 'INFO'=>'fyi', 'WARN'=>'hmm', 'ERROR'=>'wtf', 'FATAL'=>'omg', 'UNKNOWN'=>'???'}
  SEVERITY_TO_COLOR_MAP   = {'DEBUG'=>'0;37', 'INFO'=>'32', 'WARN'=>'33', 'ERROR'=>'31', 'FATAL'=>'31', 'UNKNOWN'=>'37'}
  PROTOCOL_COLOR          = 34
  USE_HUMOROUS_SEVERITIES = false
  USE_COLOR_PROTOCOL      = true

  def call(severity, time, progname, msg)
    if USE_HUMOROUS_SEVERITIES
      formatted_severity = sprintf("%-3s","#{SEVERITY_TO_TAG_MAP[severity]}")
    else
      formatted_severity = sprintf("%-5s","#{severity}")
    end

    formatted_time = time.strftime("%Y-%m-%d %H:%M:%S.") << time.usec.to_s[0..2].rjust(3)
    color = SEVERITY_TO_COLOR_MAP[severity]

    unless msg.blank?
      msg.gsub!(/POST|GET|PUT|DELETE/) {|r| "\033[#{PROTOCOL_COLOR}m#{r}\033[0m"} if USE_COLOR_PROTOCOL
      "\033[0;37m#{formatted_time}\033[0m [\033[#{color}m#{formatted_severity}\033[0m] #{msg.strip} (pid:#{$$})\n"
    end
  end

end

Rails.logger.formatter = Formatter.new