ruby parallelism

console

irb(main):003:0> fs.fetch_serial
Google
Google
SPIEGEL ONLINE - Nachrichten
IT-News, c't, iX, Technology Review, Telepolis | heise online
Golem.de: IT-News für Profis
Planet RubyOnRails | Working with a wealth of web servers and databases
Ruby on Rails
took: 12.69326297 seconds
=> nil
irb(main):004:0> fs.fetch_parallel
Google
Google
Golem.de: IT-News für Profis
SPIEGEL ONLINE - Nachrichten
Ruby on Rails
IT-News, c't, iX, Technology Review, Telepolis | heise online
Planet RubyOnRails | Working with a wealth of web servers and databases
took: 2.317157908 seconds

fetch sites

class FetchSites
  attr_reader :sites
  def initialize
    @sites = ["google.com", "google.de", "spiegel.de", "heise.de", "golem.de", "planetrubyonrails.org", "rubyonrails.org"]
  end

  def fetch_serial
    start_time = Time.now
    sites.each do |site|
      agent = Mechanize.new
      page = agent.get("http://#{site}")
      puts page.title
    end

    end_time = Time.now
    puts "took: #{end_time - start_time} seconds"
  end

  def fetch_parallel
    start_time = Time.now
    threads = []

    sites.each do |site|
      threads << Thread.new do
        agent = Mechanize.new
        page = agent.get("http://#{site}")
        puts page.title
      end
    end

    threads.each do |thread|
      thread.join
    end

    end_time = Time.now
    puts "took: #{end_time - start_time} seconds"
  end
end

Gemfile

source 'https://rubygems.org'

gem 'rails', '3.2.8'

# Bundle edge Rails instead:
# gem 'rails', :git => 'git://github.com/rails/rails.git'

gem 'sqlite3'


# Gems used only for assets and not required
# in production environments by default.
group :assets do
  gem 'sass-rails',   '~> 3.2.3'
  gem 'coffee-rails', '~> 3.2.1'

  # See https://github.com/sstephenson/execjs#readme for more supported runtimes
  # gem 'therubyracer', :platforms => :ruby

  gem 'uglifier', '>= 1.0.3'
end

gem 'jquery-rails'
gem 'ember-rails'
gem 'therubyracer'
gem 'mechanize'

# To use ActiveModel has_secure_password
# gem 'bcrypt-ruby', '~> 3.0.0'

# To use Jbuilder templates for JSON
# gem 'jbuilder'

# Use unicorn as the app server
# gem 'unicorn'

# Deploy with Capistrano
# gem 'capistrano'

# To use debugger
# gem 'debugger'