Event Collaboration for the Rubyist

Transcript

1. Event Collaboration for the Rubyist by Luismi Cavallé
2. twitter.com/cavalle github.com/cavalle
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
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