Whoops! Where did my architecture go?

Slides of the talk I gave at GOTO London, 2016.

Transcript

1. Whoops!
   Where did my architecture go? In between a monolith and a system of systems mess… / @olivergierke
4. Background Consulting & engineering @ Pivotal Lots of code reviews Eoin Woods‘ talk on InfoQ
5. Roadmap Divide and conquer Of layers and slices The modular monolith
6. Divide and conquer
7. Component Single unit to understand
8. Component Single unit to change
9. Component Scope of risk of change
10. B Smaller unit to understand A
11. B Reduced risk of change A
12. B Cost of separation A
13. B Definition and maintenance
    of dependencies A
14. Of layers
    and slices…
15. Presentation Service Data Access Billing Inventory Order
16. Layers Well understood Known to developers Less important to business
17. Slices Hardly understood New to developers Key for business requirements
18. Presentation Service Data Access Billing Inventory Order
19. Monolith
 VS.
    System of Systems
20. Monolith VS. System of Systems Order Inventory Billing Order Inventory Billing
21. In-process calls VS. Inter-process calls Order Inventory Billing Order Inventory Billing
22. Performance? Overhead? Error scenarios? Order Inventory Billing Order Inventory Billing
23. " If you can’t build a modular monolith, why do you think microservices are the answer? — Simon Brown
24. How to manage modularity in different architectural contexts?
25. Means to enforce context boundaries? Order Inventory Billing Order Inventory Billing
26. The modular monolith
27. How to implement
 a modular monolith?
28. How to maintain
 a modular monolith?
29. Bounded Context
 all the things! Domain-Driven Design is a great idea! Surprise! In a monolith, too!
30. Architecturally- evident code
31. Code analysis jDepend Sonarcube Structure 101 / Sonargraph jQAssistant
32. A plain Java
    based approach
33. How to write code that’s less likely to deteoriate?
34. Presentation Service Data Access Billing Inventory Orders
35. Packages
36. ….layer.slice
    ….slice.layer
    ….slice
37. ….web.core
    ….service.core
    ….repository.core
38. ….core.web
    ….core.service
    ….core.repository
39. ….core
    ….customer
    ….account
40. Does it make a difference?
41. Dependency management
42. Orders Inventory Billing Orders Inventory Billing
43. A rule violation is just an @Inject away! Orders Inventory Billing
44. You only need to manage
 what you can refer to…
45. Layers first Leaks slice internals Lower layers visible to everyone
46. Needs to be public :( Allows other code to circumvent business logic
47. Slices only Keeps technical division private Encapsulates business module Internals understood anyway
48. All package protected Compiler induced dependency control
49. Presentation Service Data Access Billing Inventory Order
50. Presentation Service Data Access Billing Inventory Order
51. Resources Blogpost Sonargraph jQAssistant Spring Data JPA @ GitHub
52. Sample Code http://github.com/olivergierke/
 whoops-architecture
53. Thanks & Credits Eoin Woods — Talk @ InfoQ Stefan Tilkov — Talk @ InfoQ