Simple logger using Ruby's built in Singleton module

singleton_logger.rb

require 'singleton'

class SimpleLogger
  include Singleton
  
  attr_accessor :level
  
  ERROR=1
  WARNING=2
  INFO=3
  
  def initialize
    @log = File.open("log.txt", "w")
    @level = WARNING
  end
  
  def error(msg)
    @log.puts(msg)
    @log.flush
  end
  
  def warning(msg)
    @log.puts(msg) if @level >= WARNING
    @log.flush
  end
  
  def info(msg)
    @log.puts(msg) if @level >= INFO
    @log.flush
  end
  
  
end

logger = SimpleLogger.instance
logger.level = SimpleLogger::INFO

logger.info('Doing the first thing')
logger.info('Doing the second thing')