Road From Hex. Architecture to Event Sourcing
Download as PPTX, PDF3 likes1,750 views
1) The document describes Carlos Buenosvinos' maturity model for application architecture, starting from "Spaghetti Architecture" and progressing through "Framework Fanboy Architecture", "Hexagonal Architecture", adding domain events, CQRS, and eventually event sourcing with CQRS. 2) It tells a story of one company's journey applying these architectural approaches to address issues like complexity, dependencies, bugs, and performance as their codebase and features grew over time. 3) Advancing through the levels involved techniques like separating concerns, delaying infrastructure decisions, improving testability, handling tasks asynchronously, splitting read and write models, and ultimately reconstructing entities from event logs for benefits like historical data and auditability.
Road From Hex. Architecture to Event Sourcing
- 1. Road from Hex. Architecture to Event Sourcing Carlos Buenosvinos (@buenosvinos) February, 05th , 2019 Porto
- 2. Carlos Buenosvinos @buenosvinos 2 VP Technology @ XING Consultant and Trainer as Hobby +10 years as CTO, VPs, Director Teams up to 100 people E-Commerce, E-Learning, Payments, Classifieds, Recruiting Atrápalo (500M EUR), PCComponentes (300M EUR)
- 3. Domain-Driven Design in PHP Carlos Buenosvinos, Christian Soronellas and Keyvan Akbary https://leanpub.com/ddd-in-php
- 9. Buenosvinos Maturity Model Level 1: Spaghetti Level 2: Framework Fanboy Level 3: Hexagonal Architecture Level 4: Hex. + Domain Events Level 5: Stepping Stone (CQRS) Level 6: Event Sourcing + CQRS 9
- 10. Buenosvinos Maturity Model Level 1: Spaghetti Level 2: Framework Fanboy Level 3: Hexagonal Architecture Level 4: Hex. + Domain Events Level 5: Stepping Stone (CQRS) Level 6: Event Sourcing + CQRS 10
- 11. I want to tell 1 1 you a real story about…
- 13. I don’t rewrite Apps from Scratch 13
- 16. Level 1: Spaghetti Architecture • Multiple Application Entry Points - create_user.php, delete_user.php, … • Infrastructure and Domain Together - PHP and SQL within HTML • Lack of Testing • Difficult to Maintain 1 6
- 17. New App Old App Matching by URL Moving Away: Middleware Approach https://carlosbuenosvinos.com/migrating-progressively-to-symfony-without-pain-with-stackphp/
- 18. Level 2: Layered Architecture / Framework Fanboy Architecture • Single Application Entry Point - app.php • Some structure is present (MVC) • Still Mixing Infrastructure and Domain - Long Controllers with SQL and Business Logic, Dummy Entities (getters and setters) • No testing or using Web Framework • Difficult to upgrade Infrastructure Components 1 8
- 26. Moving to Hexagonal Architecture • Pick an action in the Web Controller - Coloring Exercise: Identify Infrastructure references (ORM, HTTP Rest Calls, Caching, etc.) - Extract Variable and to the top • Extract Business Logic into Application Services (Copy and Paste) • Move Infrastructure references away - Interfaces Infrastructure and the Rest - Database Tx can be move to Repositories • Start Unit Testing from Application Services 26
- 30. Benefits of Hexagonal Architecture • Separation of Concerns • Decoupled from the Framework • Delays Infrastructure Decisions - Persistence Storage or Delivery Mechanism (Web, API, CLI, etc.) • Easy to Test - Testing Application Services (or CH) - Testing Entities - Mocking between the boundaries 30
- 32. New Tech Policies in the Team: 1. Everything New: Hexagonal Architecture 2. Touching an Old Feature: Boy Scout Rule ("Always leave the campground cleaner than you found it.”) 3. 100% Coverage in the Application Services 32
- 34. Buenosvinos Maturity Model Level 1: Spaghetti Level 2: Framework Fanboy Level 3: Hexagonal Architecture Level 4: Hex. + Domain Events Level 5: Stepping Stone (CQRS) Level 6: Event Sourcing + CQRS 34
- 35. At this point, 35 you can be consultant too!
- 36. “… and I want to notify the user by email, logging and sending a BI tracking” Company’s Product Owner 36
- 37. 2 2
- 38. Team starts to face new issues • # of Dependencies Grows • Application Service complexity Grows • More Chances to Introduce Bugs - More developers touching the same file (Main Task and Subtasks mixed) • More Subtasks in the same feature, Worse Performance!! 38
- 49. TechPoliciesAdded (ok, it’s a bad joke!) 1. Subtasks of a Feature are developed in a different Application Service and attached via Listener 2. Fire any new Event that Business may be interested 3. Let’s have a TV screen to monitor realtime Business metrics to be proactive. 49
- 51. Buenosvinos Maturity Model Level 1: Spaghetti Level 2: Framework Fanboy Level 3: Hexagonal Architecture Level 4: Hex. + Domain Events Level 5: Stepping Stone (CQRS) Level 6: Event Sourcing + CQRS 51
- 52. “Hey team! Have you realised that the item page is getting quite slow?” Company’s Product Owner 52
- 53. Perfomance! 53 Multiple Costly Requests (#, external, joins, etc.)
- 55. 55
- 56. Restaurant Page 1 Query Redis o Elastic WorkerDomain Event Command (Application Service) RESPONSIBILITY SEGREGATION (CQRS)
- 58. NOT PROPER CQRS
- 59. Problem #1: 2 Infras / 1 Tx 59
- 60. What strategies to deal with these inconsistencies can we follow? • Let inconsistencies happen - The Command Handler will manage itself (firing ArticleWasAdded, sent to RabbitMQ, but failed Database Tx) - Feasible for most operational tasks (sending email, non-critical tracking, etc.) • New Article Added Action and its Event persisted in the same Tx. Then Worker to move Events to Rabbit. • Global TX (Noooooooooo!) 60
- 65. Buenosvinos Maturity Model Level 1: Spaghetti Level 2: Framework Fanboy Level 3: Hexagonal Architecture Level 4: Hex. + Domain Events Level 5: Stepping Stone (CQRS) Level 6: Event Sourcing + CQRS * Tested with just 20 companies aprox. 65
- 67. Buenosvinos Maturity Model Level 1: Spaghetti Level 2: Framework Fanboy Level 3: Hexagonal Architecture Level 4: Hex. + Domain Events Level 5: Stepping Stone (CQRS) Level 6: Event Sourcing + CQRS 67
- 68. Moving to Event Sourcing • Every Entity is reconstituted from Events • Benefits: • Historical Logs of our Entities • Audit Environments • Realtime processing • Reproduce environments up to specific state 68
- 70. Our Main Database is nothing but a Cache (Can we get rid of it? How much does it cost?) 70
- 74. Buenosvinos Maturity Model Level 1: Spaghetti Level 2: Framework Fanboy Level 3: Hexagonal Architecture Level 4: Hex. + Domain Events Level 5: Stepping Stone (CQRS) Level 6: Event Sourcing + CQRS 74
- 76. @buenosvinos 7 6
- 77. Thank you for your attention.