Clean Architecture

Recording https://www.youtube.com/watch?v=5vVtBSaSxog

Transcript

1. Ivan Paulovich @ivanpaulovich Stockholm, 2020 Nov 18th Clean Architecture
2. @ivanpaulovich
3. The “Software Architecture” Presentation Layer ASP.NET MVC and Autofac Business Layer MediatR and AutoMapper Data Layer Entity Framework and Dapper Database and Messaging SQL Server and RabbitMQ IDE and Tools Visual Studio, Resharper and .NET Framework 3 @ivanpaulovich
4. The “Software Architecture” Presentation Layer ASP.NET MVC and Autofac Business Layer MediatR and AutoMapper Data Layer Entity Framework and Dapper Database and Messaging SQL Server and RabbitMQ IDE and Tools Visual Studio, Resharper and .NET Framework 4 @ivanpaulovich Not a Software Architecture!
5. What is the Clean Architecture Style? @ivanpaulovich
6. Each of these architectures produce systems that are: • Independent of Frameworks. • Testable. • Independent of UI. • Independent of Database. • Independent of any external agency. https://blog.cleancoder.com/uncle-bob/2012/08/13/the-clean-architecture.html “ @ivanpaulovich
7. @ivanpaulovich
8. Clean Architecture Style @ivanpaulovich Clean Architecture Style
9. Clean Architecture Style @ivanpaulovich Clean Architecture Style Hexagonal Architecture Style Clean Architecture Style @ivanpaulovich
10. Clean Architecture Style @ivanpaulovich Clean Architecture Style Hexagonal Architecture Style Ports and Adapters Pattern Dependency Inversion
 Principle Test-Driven Development Clean Architecture Style @ivanpaulovich
11. Clean Architecture Style Hexagonal Architecture Style Ports and Adapters Pattern Dependency Inversion
 Principle Test-Driven Development Clean Architecture Style Object-Oriented Design
 Principles Use Cases as Central Organising Structure Pluggable User Interface @ivanpaulovich
12. Hexagonal Architecture Style 1. Ports and Adapters pattern. 2. The implementation is guided by tests. 3. It is decoupled from technology details. @ivanpaulovich
13. Business @ivanpaulovich 13 Ports and Adapters Cloud 
 Messaging UI In Memory 
 Persistence 
 Tests In Memory 
 Messaging 
 SQL
14. Business @ivanpaulovich 14 Ports and Adapters Cloud 
 Messaging UI In Memory 
 Persistence 
 Tests In Memory 
 Messaging 
 SQL Ports
15. Ports @ivanpaulovich
16. Business v @ivanpaulovich 16 Ports and Adapters Cloud 
 Messaging UI In Memory 
 Persistence 
 Tests In Memory 
 Messaging 
 SQL Adapters
17. Adapters
18. Application Unit Test Web Database Domain Primary Actors Secondary Actors @ivanpaulovich 18 Infrastructure Ports and Adapters
19. A Web of Objects @ivanpaulovich
20. ? ? ? Test Expectations @ivanpaulovich A Web of Objects
21. The First Test Deposit 
 Use Case Customer 
 Repository Account Repository Test Expectations @ivanpaulovich
22. The Walking Skeleton Deposit 
 Use Case Customer 
 Repository Account Repository Fakes User 
 Interface @ivanpaulovich
23. Deposit 
 Use Case Customer 
 Repository Account Repository Fakes User 
 Interface Integration Tests s Account Repository Test Customer 
 Repository
24. A Wallet Application Deposit Withdraw Transfer Close Account Open Account Database Persistence Exchange Service User Interface Exchange Rates API In Memory SQL In Memory Security @ivanpaulovich
25. Services Controllers Repositories Use Cases Domain Unit Tets Fake API Fake DB Unit Tests @ivanpaulovich
26. Services Controllers Repositories Use Cases Domain Component 
 Tests HTTP Component Tests @ivanpaulovich Fake API Fake DB
27. Services Controllers Repositories Use Cases Domain External APIS Database TCP HTTP Integration Tests Integration Tests @ivanpaulovich
28. Application External APIS Database End to End 
 Tests HTTP TCP HTTP End to End Tests @ivanpaulovich
29. Use Cases • Use Cases show the intent of a system. • Use Cases are delivery independent. • Use Cases are algorithms that interpret the input to generate the output data. • Use Cases diagrams highlight the Primary and secondary actors. 29 @ivanpaulovich
30. Controller Use Case Core User Interface @ivanpaulovich Request Response Input Output • Abstract • General • Stable • Consistent • Concrete • Speci f i c • Unstable • Inconsistent
31. Deposit Use Case @ivanpaulovich
32. Deposit Use Case Input and Output Messages @ivanpaulovich
33. Object-Oriented Design Principles
34. Entities Entities Clean Architecture Entities Use Cases Controllers Gatew ays Presenters D evices W eb UI DB External Interfaces @ivanpaulovich •Abstractness increases with stability. •Modules depend in the direction of stability. •Classes that change together are packaged together.
35. Entities Use Cases Controllers Presenters Gateways Devices UI DB Web External Interfaces Abstract,
 General,
 Stable,
 Consistent Concrete,
 Speci f i c, 
 Unstable, Inconsistent Level Clean Architecture @ivanpaulovich
40. Takeaways • Clean Architecture is about usage and the use cases are the central organising structure. • Use cases implementation are guided by tests. • The User Interface and Persistence adapters are designed to ful f i l the core needs (not the opposite!). • Defer decisions by implementing the simplest component f i rst. 40 @ivanpaulovich
41. @ivanpaulovich