An example of using STDOUT Logger in Ruby

logger_example_stdout.rb

# http://www.ruby-doc.org/stdlib-2.1.0/libdoc/logger/rdoc/Logger.html
require 'logger'

class CoffeeShop
  attr_reader :logger

  def initialize(name)
    @name = name
    @menu = []
    @logger = Logger.new(STDOUT)
  end

  def introduce_coffee(coffee)
    logger.debug "introducing a new coffee #{coffee}"
    @menu.push(coffee)
    log_menu_item_count
  end

  def withdraw_coffee(coffee)
    logger.debug "withdrawing a new coffee #{coffee}"
    @menu.delete(coffee)
    log_menu_item_count
  end

private
  def log_menu_item_count
    logger.debug "menu item count: #{@menu.count}"
  end
end

shop = CoffeeShop.new("Costa")
shop.introduce_coffee("Angkorian")
shop.introduce_coffee("Vietnamese")
shop.withdraw_coffee("Angkorian")