Book Image

Get Your Hands Dirty on Clean Architecture

By : Tom Hombergs
Book Image

Get Your Hands Dirty on Clean Architecture

By: Tom Hombergs

Overview of this book

Building for maintainability is key to keeping development costs low and processes easy. The second edition of Get Your Hands Dirty on Clean Architecture is here to equip you with the essential skills and knowledge to build maintainable software. With this comprehensive guide, you’ll explore the drawbacks of conventional layered architecture and the advantages of domain-centric styles such as Robert C. Martin's Clean Architecture and Alistair Cockburn's Hexagonal Architecture. Then, you’ll dive into hands-on explanations on how to convert hexagonal architecture into actual code. You'll learn in detail about different mapping strategies between the layers of hexagonal architecture and discover how to assemble the architectural elements into an application. Additionally, you’ll understand how to enforce architecture boundaries, which shortcuts produce what types of technical debt, and how, sometimes, it is a good idea to willingly take on those debts. By the end of this second edition, you'll be armed with a deep understanding of the hexagonal architecture style and be ready to create maintainable web applications that save money and time.
Table of Contents (13 chapters)

Slicing Port Interfaces

One question that comes to mind when implementing services is how to slice the port interfaces that define the database operations available to the application core.

It's common practice to create a single repository interface that provides all database operations for a certain entity, as shown in the following figure:

Figure 6.2: Centralizing all database operations into a single outgoing port interface makes all services depend on methods they don't need

Each service that relies on database operations will then have a dependency on this single "broad" port interface, even if it uses only a single method from the interface. This means we have unnecessary dependencies in our codebase.

Dependencies on methods that we don't need in our context make the code harder to understand and to test. Imagine we are writing a unit test for RegisterAccountService from the preceding figure. Which of the methods of the AccountRepository interface...