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Event Collaboration for the Rubyist

Event Collaboration for the Rubyist

Luismi Cavallé

December 29, 2011
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  1. Event Collaboration for the Rubyist by Luismi Cavallé

  2. twitter.com/cavalle github.com/cavalle

  3. None
  4. Event Collaboration?

  5. Multiple components work together by communicating with each other by

    sending events when their internal state changes. — Martin Fowler http://tinyurl.com/eaaDev
  6. Given one task is pending When I complete it Then

    my boss is noti ed Given I completed one task in 1 day And I completed other task in 2 days When I see the performance report Then my performance is 1.5 tasks/day
  7. class Task def mark_as_completed! update_attributes! :completed => true notify_boss update_progress_report

    end def notify_boss # ... end def update_progress_report # ... end end
  8. The Single Responsibility Principle “An object should have only a

    single responsibility.” — Uncle Bob http://tinyurl.com/OOPrinciples
  9. class Task def mark_as_completed! update_attributes! :completed => true Notifier.notify_task_completed self

    ProgressReport.update_performance self end end
  10. The Open Closed Principle “[An object] should be open for

    extension, but closed for modi cation.” — Uncle Bob http://tinyurl.com/OOPrinciples
  11. class Task def mark_as_completed! update_attributes! :completed => true publish_event :task_completed,

    :task_name => name, :by => user.name end # ... end
  12. class Notifier on :task_completed do |event| Notifier.new(:email => find_boss_email(event.by), :subject

    => "Task #{event.task_name} completed").send! end # ... end
  13. module PerformanceStats on :task_created do |event| start_times[event.task_name] = Time.now end

    on :task_completed do |event| completion_time_sum += Time.now - start_times.delete(event.task_name) completion_time_count += 1 end def self.average_performance completion_time_sum / completion_time_count end # ... end
  14. Task Noti er Performance Stats

  15. Loose coupling Maintainability Scalability

  16. Un momento de relax…

  17. Eventwire Event Collaboration for the Masses http://github.com/cavalle/eventwire

  18. Interface Middleware Adapters Your App Workers RabbitMQ Redis MongoDB ZeroMQ

  19. Interface: Publisher class MyPublisher include Eventwire::Publisher def my_method publish_event :task_completed,

    :task_name => 'Name of the task', :username => 'Username' end end
  20. Interface: Subscriber class MySubscriber include Eventwire::Subscriber on :task_completed do |data|

    puts "Task completed #{data.task_name}" end end
  21. Adapters AMQP Redis MongoDB ZeroMQ Bunny InProcess Syslog

  22. Middleware MsgPack ErrorHandler Logger DataObjects JSON BSON

  23. Workers $ rake eventwire:work $ rake environment eventwire:work

  24. Con guration Eventwire.configure do |config| config.adapter = :AMQP config.logger =

    Rails.logger config.middleware << MyCustomMiddleware end
  25. P1 P2 S1 S3 S2 S2 S2 Pub / Sub

    Bus Sub. Balancing Messaging Patterns
  26. None
  27. Current status Not released to Rubygems yet Some adapters are

    very experimental Next milestone: Production at BeBanjo
  28. Future Measure & Improve Adapters New Adapters Documentation Front-end ala

    Resque
  29. Some tradeoffs Another layer of abstraction Lost messages Messages out

    of order
  30. References http://github.com/cavalle/eventwire http://tinyurl.com/eaaDev http://rubyamqp.info/

  31. ¡Gracias! twitter.com/cavalle github.com/cavalle speakerdeck.com/u/cavalle