An example of using a file Logger in Ruby

logger_file_example.rb

require 'logger'

class CoffeeShop
  attr_reader :std_logger, :file_logger

  def initialize(name)
    @name = name
    @menu = []
    @std_logger = Logger.new(STDOUT)
    @file_logger = Logger.new('./coffee_shop.log')
  end

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

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

  def log(message, level=Logger::INFO)
    std_logger.add level, message, "#{self.class} (#{@name})"
    file_logger.add level, message, "#{self.class} (#{@name})"
  end
end

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