Get started with Component-Based Rails @ RailsConf 2015

Component-based Rails helps you regain control over your sprawling Rails application. It helps you structure your new Rails application in a way that it will stay more manageable longer. It helps you think completely differently about writing applications - not just in Ruby and Rails!

This session will help you pass the initial hurdle of getting started with component-based Rails. While there is nothing really new, there is a lot that is just a little different. We will go over those differences so your start with component-based Rails is a smooth one.

Transcript

1. $ git clone https://github.com/shageman/sportsball.git $ cd sportsball $ ./build.sh
2. What brings you here?
3. Getting started with #cbra Component-Based Rails Applications RailsConf 2015, Labs Workshop
4. Stephan Hagemann @shageman shagemann@pivotal.io Pivotal Labs
5. Why #cbra?
6. Improved Communication Improved Collaboration Improved Creation Improved Maintenance Improved Comprehension
8. Communication
10. Collaboration
13. Creation
14. graphs on/off
15. Maintenance
16. reports2
17. Comprehension
20. $ git clone https://github.com/shageman/sportsball.git $ cd sportsball $ ./build.sh
21. Sportsball - what does it do?
22. Status Quo
23. Sportsball App Rails Engine Gem
24. Code Review!
25. Code Review Recap • No app folder! • App gem loaded through path (Gemfile) • App is an engine (engine.rb) • App is mounted (config/routes.rb) • App routes defined in engine (app/config/routes.rb) • App defines and loads migrations (app/db/migrate/, engine. rb) • Non-published gems are funky (both Gemfiles) • Tests are at the appropriate levels and aggregated via scripts (build.sh, test.sh) • Deployment is unchanged
26. Finding Components
27. What should be extracted first?
28. Sportsball App Rails Engine Gem
29. What is the intrinsic structure of this app?
30. 1st Refactor Extract Domain Gem
31. Sportsball App Rails Engine Gem
32. Sportsball App Rails Engine Gem Predictor
33. bundle gem predictor #answer questions rm -rf predictor/.git* Move classes, move tests Rename module (in gem) Fix tests (in gem) Load gem (in engine) Fix tests (in engine) Check build (in main app) DIY - Extract Predictor Gem
34. Code Review!
35. Code Review Recap • path … do (Gemfile) • Require gem in (lib/app.rb) • Non-test code changes only in Module names (prediction_controller.rb) • OpenStruct App::Team and App::Game (predictor_spec.rb) • Test runner is simplified (predictor/test.sh)
36. Lessons Learned • Have good tests around the refactor • Keep running those tests! • Run tests inside out (up the dependency graph) • Reduce component dependencies as much as possible ◦ Simplifies component ◦ Fewest possible reasons to change ◦ Keeps dependency graph flat
37. Sportsball App Rails Engine Gem predictor
38. What else is in this app?
39. Sportsball Rails Engine Gem Predictor Team UI Game UI Prediction UI Teams Games
40. 2nd & 3rd Refactor Push Persistence Down
41. Sportsball Rails Engine Gem Predictor Team UI Game UI Prediction UI Teams Games AR Engine
42. Sportsball Rails Engine Gem Predictor Team UI Game UI Prediction UI Teams Games AR Engine
43. rails plugin new --help rails plugin new teams -BGVSJT --mountable \ --dummy-path=spec/dummy Move classes, move tests, move migration Create table renaming migration (in teams engine) Rename module (in teams engine) Fix tests (in teams engine) Load gem (in app engine) Create testhelper (in teams engine) and use (in app engine) Fix tests (in app engine) Check build (in main app) DIY - Push Teams Persistence Down
44. Code Review!
45. Code Review Recap • Dummy app (teams/spec/dummy) • String renames of AR associations! (app/game.rb) • Teams test helper ◦ Create test helper (teams/spec/support/object_creation_methods.rb) ◦ Expose test helper (teams/lib/teams/test_helpers.rb) ◦ Use teams test helper (app/spec/spec_helper.rb)
46. Lessons Learned • Two ways of engine-out-of-engine extraction ◦ Create fresh + move + rename ◦ Duplicate + delete + rename • Don’t mess with existing migrations! ◦ Move affected existing migrations ◦ Create new migration for table rename • Test helpers nice for ActiveRecord models • “App” is a terrible name to refactor away from
47. 4th Refactor Better Naming of Component
48. Sportsball Rails Engine Gem Predictor Team UI Game UI Prediction UI Teams Games Layout WebUI AR Engine
49. Common Base Misc General Lib <My Company name> Side note: If you feel like naming your engine...
50. Everything Cruft Random Don’t Know Don’t Care Duh Here are some alternatives
51. Everything Cruft Random DontKnow DontCare Duh Here are some alternatives (Proper module names)
52. Give the most specific name you can think of refactor a lot continue the conversation
53. Sportsball Rails Engine Gem Predictor Team UI Game UI Prediction UI Teams Games AR Engine
54. Sportsball Rails Engine Gem Predictor Team UI Game UI Prediction UI Teams Games AR Engine Can we split up WebUI?
55. 5th Refactor Extract Layout and Style
56. Sportsball Rails Engine Gem Predictor Team UI Game UI Prediction UI Teams Games WebStyle AR Engine UI Engine
57. Copy WebUI into WebStyle Remove everything but assets/layout - don’t forget vendor! (in WebStyle) Remove assets (in WebUI) Fix asset loading (in WebUI) Check build (in main app) DIY - Extract WebStyle
58. Code Review!
59. Code Review Recap • No tests in WebStyle • Application layout (web_style/application.html.slim) • Layout selection (web_ui/application_controller.rb)
60. Lessons Learned • You won’t know what components you will need to extract until you try to extract something
61. 6th, 7th, 8th Refactor Separate independent UIs
62. Sportsball Rails Engine Gem Predictor Team UI Game UI Prediction UI Teams Games WebStyle AR Engine UI Engine
63. Sportsball Rails Engine Gem Predictor Team UI Game UI Prediction UI Teams Games WebStyle AR Engine UI Engine
64. Sportsball Rails Engine Gem Predictor Team UI Game UI Prediction UI Teams Games WebStyle AR Engine UI Engine
65. Sportsball Welcome UI Rails Engine Gem Predictor Team UI Game UI Prediction UI Teams Games WebStyle AR Engine UI Engine
66. Pick any one of the potential UI engines DIY - Split off a UI Engine
67. Code Review!
68. Code Review Recap • Rerouting necessary ◦ App routes (config/routes.rb) ◦ Engine routes (*_ui/config/routes.rb) ◦ Tests
69. Lessons Learned
70. Sportsball Welcome UI Rails Engine Gem Predictor Team UI Game UI Prediction UI Teams Games WebStyle AR Engine UI Engine That’s it!
71. Now - Your App!
72. leanpub.com/cbra/c/railsconf
73. cbra.info