koraktor/steam-condenser-ruby

# This code is free software; you can redistribute it and/or modify it under
# the terms of the new BSD License.
#
# Copyright (c) 2013, Sebastian Staudt

require 'logger'

# This module is included by all classes of Steam Condenser that log events
#
# It is a lightweight wrapper around Ruby's `Logger` class from the standard
# library.
module SteamCondenser::Logging

  @@formatter = ::Logger::Formatter.new

  @@level = ::Logger::Severity::WARN

  @@logdev = STDOUT

  # Creates a logger for the class that includes this module
  #
  # Additionally it defines a `.log` singleton method for the class that
  # includes this module
  #
  # @param [Class] klass The class that includes this module
  def self.included(klass)
    klass.send :class_variable_set, :@@logger, nil
    klass.define_singleton_method :log do
      logger = class_variable_get :@@logger
      if logger.nil?
        logger = ::Logger.new @@logdev
        logger.formatter = @@formatter
        logger.level = @@level
        logger.progname = klass.name

        class_variable_set :@@logger, logger
      end
      logger
    end
  end

  # Sets the default formatter to use for all logging events in Steam
  # Condenser
  #
  # @param [#call] formatter The formatter to use when logging
  def self.formatter=(formatter)
    @@formatter = formatter
  end

  # Sets the default logging device to use for all logging events in Steam
  # Condenser
  #
  # @param [IO] logdev For example an output stream or file to log to
  def self.logdev=(logdev)
    @@logdev = logdev
  end

  # Sets the default log level to use for filtering all logging events in
  # Steam Condenser
  #
  # @param [Fixnum] level The log level to use when logging
  def self.level=(level)
    @@level = level
  end

  # Returns the logger for the current class
  #
  # @return [Logger] The logger for the current class
  def log
    self.class.log
  end

end