This document contains notes from a Domain-Driven Design workshop on separating user profile, authentication, and profiling subdomains into distinct bounded contexts with their own models and databases. It discusses using UUIDs to decentralize ID generation across the contexts and monitoring domain events using ActiveSupport::Notifications to help maintain consistency between bounded contexts while keeping them loosely coupled and easy to test. Some tradeoffs of this approach are that it can expose more business domain complexity, require more code, and potentially impact database performance and consistency maintenance due to data duplication.

2. Volodymyr Byno
github.com/vbyno
volodymyr.byno@gmail.com
development lead at

3. Data & Bounded
Contexts

4. Robert
Andrzej
Mirosław
Rails DDD-workshop
19-20th September, 2016. Wroclaw

5. User.columns.count => ?
Why classes eventually reach 50 columns and hundreds of methods

9. 1 model, 3 subdomains

12. def current_user
def user_signed_in?
def authenticate_user!
def user_session

15. Authentication
Profiling
Authorization

17. how to start using UUID
decentralize id generation
"A UUID is 128 bits long, and can guarantee uniqueness across space and time."
UUID

18. 3 subdomains, 3 contexts
UUID

20. Profile

21. Authentication
Profiling

26. Events
ActiveSupport::Notifications

28. Pros:
Cons:
• Expose Business Domain Complexity
• Low Coupling
• Easy testing
• Consistency maintenance
• More code
• DB performance
• Data Duplication