The Long Ball: Upgrading Rails from 1.2 -> 4.0

RailsConf 2013 - Explore tips to upgrade from each major version to the other, and how to efficiently tackle a 1.2 -> 4.0 upgrade through two different case studies.
The velocity of change for Rails versions has a side effect -- businesses hesitate to update to the latest version until their productivity drops and they're forced to update. What happens then? Let's explore a case study of a Rails app that followed this pattern.

Transcript

1. The Long Ball:
   Upgrading Rails
   From 1.2 → 4.0
   Jesse Wolgamott | @jwo
   Thursday, May 2, 13
   

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2. Most Rails apps don't live as long as
   your entire career
   Thursday, May 2, 13
   

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3. but... what if they do?
   Thursday, May 2, 13
   

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4. Rails is not
   Wordpress and
   you cannot press
   "Upgrade".
   Thursday, May 2, 13
   

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5. In Rails, the code is
   changing constantly.
   Thursday, May 2, 13
   

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6. Thursday, May 2, 13
   

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7. And this is a good
   thing
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8. •Features
   •Security Updates
   •End of Life
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9. there are many Rails 2.3
   applications out there right
   now, chugging away and
   providing business value.
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10. What should we
    do with them?
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11. Life in a 1.x App
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12. page.replace_html('tasks-completed',
    Task.completed_count)
    page.visual_effect(:highlight,
    'task-item-' + @task.id.to_s,
    :duration => 1.0)
    http://viget.com/extend/getting-started-with-rjs-in-rails
    Thursday, May 2, 13
    

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13. <%= link_to_remote 'Mark as Complete',
    :update =>, 'task-status-' + @task.id.to_s,
    :url => {:controller => 'task',
    :action => 'mark_complete',
    :id => @task
    }
    %>
    http://viget.com/extend/getting-started-with-rjs-in-rails
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14. svn import . svn://localhost/blab -m "initial import" --
    username rbates
    cd ../
    svn co svn://localhost/blab/trunk blab
    cd blab
    cp config/database_example.yml config/database.yml
    svn propset svn:ignore database.yml config/
    svn propset svn:ignore "*" log/
    svn propset svn:ignore "*" tmp/
    http://railscasts.com/episodes/36-subversion-on-rails
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15. Life in a 2.3 App
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16. Rails::Initializer.run do |config|
    config.gem "haml"
    config.gem "chronic", :version => '0.2.3'
    config.gem "hpricot", :source => "http://
    code.whytheluckystiff.net"
    config.gem "aws-s3", :lib => "aws/s3"
    end
    rake gems:install
    http://archives.ryandaigle.com/articles/2008/4/1/what-s-
    new-in-edge-rails-gem-dependencies
    Thursday, May 2, 13
    

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17. User.find(:all, :limit => 1)
    User.find(:all)
    User.find(:first)
    User.first(:conditions => {:name => 'lifo'})
    User.all(:joins => :items)
    http://m.onkey.org/active-record-query-interface
    Thursday, May 2, 13
    

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18. How We
    Romanticize
    Rails 2.3
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19. Life in a 3.0 App
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20. Article.where("published_at <= ?", Time.now).includes(:comments)
    scope :published, lambda { where(published: true)}
    Article.first
    http://railscasts.com/episodes/202-active-record-queries-in-
    rails-3
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21. class Person
    include ActiveModel::Validations
    attr_accessor :title
    validates :title, :presence => true
    end
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22. Railscasts::Application.routes.draw do
    root :to => "episodes#index"
    resources :spam_checks
    resources :spam_reports do
    member do
    post :confirm
    end
    end
    end
    http://railscasts.com/episodes/226-upgrading-to-rails-3-
    part-2
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23. Life in a 3.1 App
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24. //= require jquery
    //= require jquery_ujs
    //= require_tree .
    http://guides.rubyonrails.org/asset_pipeline.html
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25. /*
    *= require_self
    *= require_tree .
    */
    http://guides.rubyonrails.org/asset_pipeline.html
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26. http://guides.rubyonrails.org/asset_pipeline.html
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27. Life in a 3.2 App
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28. • .pluck(:id)
    • Better all around (faster)
    • mass_assignment (attr_accessible)
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29. Quick look at 4.0
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30. • Wicked Awesome Postgres Features
    • Cooler Caching & strong_parameters
    • Turbolinks
    • Best Rails I’ve used
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31. Upgrade by
    Rewrite
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32. Upgrade by
    Refactor
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33. The Decision to Rewrite
    is not a technical decision
    - it is a organizational
    decision
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34. If you rewrite,
    you’ll likely fail
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35. Fail to: Recreate
    every single
    feature
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36. Fail to: Keep
    product
    momentum
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37. Fail to: Show users
    you did anything
    worthwhile
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38. When should you
    rewrite?
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39. php on Rails
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40. Vendored Rails /
    Gems
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41. Instead: Rewrite
    by Refactoring
    Tiny Wins
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42. The main upgrade
    pains
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43. Rails 2.3 Rails 3.0 Rails 3.1 Rails 4.0
    Gems Router
    JavaScript
    Queries
    CSS
    JavaScript
    Forms
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44. • Get to Rails 2.3 with bundler
    • Get to Rails 3.0 with Arel
    • Get to Rails 3.1 with Asset Pipeline
    • Get to Rails 4.0 with Gemfile
    updates
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45. • Tip! use featured extracted gems
    during your 3.0 upgrade
    • prototype_rails
    • rails_autolink
    • deprecated_finders
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46. Let's talk about
    Authentication
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47. Thursday, May 2, 13
    

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48. Always be
    Upgrading
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49. The Checklist
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50. rails-upgrade-
    checklist.com
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51. Thursday, May 2, 13
    

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52. Thursday, May 2, 13
    

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53. Thursday, May 2, 13
    

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54. @jwo
    Ruby o Rails
    rails-upgrade-
    checklist.com
    Thursday, May 2, 13
    

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