#367 Celluloid pro

Jul 18, 2012 | 11 minutes | Tools

Celluloid puts an object-oriented spin on multi-threaded development. Here I cover the fundamental features of Celluloid in several examples.

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terminal

gem install celluloid
irb -r ./rocket
ruby feed_counter.rb http://rss.cnn.com/rss/cnn_topstories.rss http://feeds.feedburner.com/railscasts http://stackoverflow.com/feeds
irb -r ./feed_counter

irb

r = Rocket.new
r.launch
r.launch!
r2 = Rocket.new
Thread.list.size
r.launch!; r2.launch!
l = Launcher.new
l.launch_rocket
Rocket.supervise(true)
f = FeedCounter.new("http://feeds.feedburner.com/railscasts")
future = f.future(:count)
future.value

rocket.rb

require 'celluloid'
class Rocket
 include Celluloid
 
 def initialize(autolaunch = false)
 launch! if autolaunch
 end
 def launch
 3.downto(1) do |n|
 puts "#{n}..."
 sleep 1
 raise "Houston, we have a problem" if [true, false].sample
 end
 puts "Blast off!"
 end
end
class Launcher
 include Celluloid
 trap_exit :relaunch
 def launch_rocket
 Rocket.new_link.launch!
 end
 
 def relaunch(actor, reason)
 launch_rocket
 end
end

feed_counter.rb

require 'rss'
require 'open-uri'
require 'celluloid'
class FeedCounter
 include Celluloid
 
 def count(url)
 open(url) do |f|
 rss = RSS::Parser.parse(f.read, false)
 count = rss.items.size
 puts "#{count} in #{url}"
 count
 end
 end
end
pool = FeedCounter.pool(size: 6)
futures = $*.map { |url| pool.future(:count, url) }
total = futures.map(&:value).inject(:+)
puts "#{total} total" if total