Ruby - share logger instance among module/classes

Question

Working on a little Ruby script that goes out to the web and crawls various services. I\'ve got a module with several classes inside:

module Crawler
  class          


        

Answer 1

Although an old question, I thought it worthwhile to document a different approach.

Building on Jacob's answer, I would suggest a module that you can add in as and when needed.

My version is this:

# saved into lib/my_log.rb

require 'logger'

module MyLog

  def self.logger
    if @logger.nil?
      @logger = Logger.new( STDERR)
      @logger.datetime_format = "%H:%M:%S "
    end
    @logger
  end

  def self.logger=( logger)
    @logger = logger
  end

  levels = %w(debug info warn error fatal)
  levels.each do |level|
    define_method( "#{level.to_sym}") do |msg|
      self.logger.send( level, msg)
    end
  end
end

include MyLog

I have this saved into a library of handy modules, and I would use it like this:

#! /usr/bin/env ruby
#

require_relative '../lib/my_log.rb'

MyLog.debug "hi"
# => D, [19:19:32 #31112] DEBUG -- : hi

MyLog.warn "ho"
# => W, [19:20:14 #31112]  WARN -- : ho

MyLog.logger.level = Logger::INFO

MyLog.logger = Logger.new( 'logfile.log')

MyLog.debug 'huh'
# => no output, sent to logfile.log instead

I find this a lot easier and more versatile than other options I've looked at so far, so I hope it helps you with yours.