This document discusses delayed_job, a database backed asynchronous processing gem for Ruby on Rails. It introduces why background processing is needed for tasks like sending emails, resizing images, and geocoding. Delayed_job allows these types of tasks to be processed asynchronously in the background without blocking the user experience. The document provides an overview of how to setup delayed_job, enqueue jobs, and run worker processes to process the queued jobs. It recommends delayed_job for any site with significant background processing needs.

1. "Maybe we should have a talk on delayed_job"
@subelsky

2. An Introduction to
delayed_job
@bmoreonrails
2009-11-10

3. I’m @jonathanjulian

4. Why do we need
background processing?

5. User Experience

6. Sending an email

7. Resizing an image

8. Updating a web service

9. Geocoding

10. Batch import

12. Delayed::Job
“Extracted from Shopify”
database-persisted queue
0..n runners

13. tobi/delayed_job

14. collectiveidea/delayed_job

15. Setup

16. gem

17. The Queue

18. One db migration

20. Let’s delay something

21. Notifier.deliver_activation_instructions(self)

22. Notifier.send_later(:deliver_activation_instructions,
self)

23. Easy!

24. class Notifier
def deliver_activation_instructions(user)
# ...
end
handle_asynchronously :deliver_activation_instructions
end

25. Custom jobs

26. class LongRunningJob < Struct.new(:id)
def perform
# do some crazy long calculations
end
end
Delayed::Job.enqueue LongRunningJob.new(42)

27. Who runs the jobs?

29. Workers

30. rake jobs:work # Start a delayed_job worker.

31. script/delayed_job start
* collectiveidea/delayed_job only

32. Production Deployment

33. # play nice with Passenger
require 'delayed/recipes'
after "deploy:update_code", "delayed_job:stop"
after "deploy:restart", "delayed_job:start"

34. http://railstips.org/
2008/11/19/delayed-
gratification-with-rails

35. "I highly recommend
DelayedJob to anyone
whose site is not 50%
background work."
@defunkt

36. @jonathanjulian
http://jonathanjulian.com/

37. Photo Attributions
• http://www.flickr.com/photos/aloshbennett/540105576/
• http://www.flickr.com/photos/gyrus/132436475/
• http://www.flickr.com/photos/gavatron/866650954/