Ruby Fundamental - Módulos para definir métodos globais

modulos_metodos_globais_01.rb

require 'logger'

module CoolLog
  def logger
    @cool_log_logger ||= ::Logger.new(STDOUT)
  end

  def level
    @cool_log_level ||= :info
  end

  def level=(value)
    @cool_log_level = value
  end

  def log(message)
    logger.send(level, message)
  end
end

modulos_metodos_globais_02.rb

class MyClass1
  include CoolLog
end

m1 = MyClass1.new

m1.level # => :info
m1.log "Informando..." # => I, [2012-04-30T08:25:22.436474 #2601]  INFO -- : Informando...

m1.level = :debug
m1.log "Debugando..." # => D, [2012-04-30T08:25:22.437045 #2601] DEBUG -- : Debugando...

modulos_metodos_globais_03.rb

class MyClass2
  extend CoolLog
end

MyClass2.level # => :info
MyClass2.log "Informando..." # => I, [2012-04-30T08:43:37.252694 #2654]  INFO -- : Informando...

MyClass2.level = :debug
MyClass2.log "Debugando..." # => D, [2012-04-30T08:43:37.252736 #2654] DEBUG -- : Debugando...

modulos_metodos_globais_04.rb

class MyClass3
  extend CoolLog
end

class MyClass4
  extend CoolLog
end

MyClass3.level # => :info
MyClass4.level # => :info

MyClass3.level = :debug

MyClass3.level # => :debug
MyClass4.level # => :info

modulos_metodos_globais_05.rb

module MyModule
  extend CoolLog
end

MyModule.level # => :info
MyModule.log "Informando..." # => I, [2012-04-30T09:07:20.251521 #2740]  INFO -- : Informando...

MyModule.level = :debug
MyModule.log "Debugando..." # => D, [2012-04-30T09:07:20.251561 #2740] DEBUG -- : Debugando...