Abstracting your Application away from Rails

Ruby on Rails makes building web applications extremely easy. All you need is an idea, the Rails Guides, and a little programming experience and you can have an application up and running in no time. However, time after time we have seen businesses paralyzed by applications built in this manner. As the business grows, the application must grow as well to accommodate the changing needs of the business. However, as a result of the coupling to Rails, the growing application becomes rigid (hard to change), fragile (easy to break), and immobile (hard to reuse). Eventually, development will slow to a halt and the business will have no room to grow. In this talk I discuss how abstracting your application away from Rails will allow you to continuously improve the application without bringing development to a halt. I will also analyze the costs and the benefits of this abstraction, as well as a case study on how to do it.

Transcript

1. Abstracting your Application away from Rails Myles Megyesi
2. Continuously deliver business value
3. • Maintainable • Extensible • Flexible
4. • Rigid (hard to change) • Fragile (easy to break) • Immobile (hard to reuse) However...
5. Business is crippled
6. Symptoms • Rigid • Fragile • Immobile • Viscous • Needless Complexity • Needless Repetition • Opacity
7. Poor Design
8. What is the design of a Rails app?
9. The design of an application is an abstract construct that has to do with the overall shape and structure of the program as well as the detailed shape and structure of each module, class and method. [Robert Martin, Agile Software Development: Principles Patterns and Practices, 87]
10. Two levels of design... • Overall • Detailed
11. What defines the overall behavior of a Rails app?
12. What defines the detailed behavior of a Rails app?
13. How does this go wrong?
14. Designs start to degrade because business requirements change in ways that the initial design did not anticipate. Often, these changes need to be made quickly, and they may be made by developers who are not familiar with the original design philosophy. [Martin 89]
15. The original design did not respond well to change.
16. If we want our Rails apps to be successful, we need to have extensible designs.
17. How do we do this?
18. What makes a designs hard to change?
19. Class Client Client Client Client Client Client Client Client Client Client Client Client Client Client Client Client Client Client Client Client
20. Controllers Controllers Controllers Controllers Controllers Controllers Models Business Rule Business Rule Business Rule Business Rule Business Rule Business Rule Models Business Rule Business Rule Business Rule Business Rule Business Rule Business Rule Models Business Rule Business Rule Business Rule Business Rule Business Rule Business Rule Models Business Rule Business Rule Business Rule Business Rule Business Rule Business Rule Models Business Rule Business Rule Business Rule Business Rule Business Rule Business Rule Models Views Views Views Views Views Views
21. Dependency Inversion Depend on abstractions, not concretions
22. Controllers Controllers Controllers Controllers Controllers Controllers Views Views Views Views Views Views Abstraction Models Business Rule Business Rule Business Rule Business Rule Business Rule Business Rule Models Business Rule Business Rule Business Rule Business Rule Business Rule Business Rule Models Business Rule Business Rule Business Rule Business Rule Business Rule Business Rule Models Business Rule Business Rule Business Rule Business Rule Business Rule Business Rule Models Business Rule Business Rule Business Rule Business Rule Business Rule Business Rule Business Rules
23. How do we make business rules an abstraction? Move them out of Rails.
24. Payroll
25. Employee Payment Classification Hourly Salary Commission
26. Rails Application Data Store
27. Cost
28. Its hard...
29. ...and there is no perfect solution.
30. Benefit
31. Extensible
32. Build abstractions around your business rules to adapt well to change
33. Continuously deliver business value