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)

Clean Architecture

Robert C. Martin cemented the term "clean architecture" in his book of the same name (Clean Architecture by Robert C. Martin, Prentice Hall, 2017, Chapter 22). In clean architecture, in his opinion, the business rules are testable by design and independent of frameworks, databases, UI technologies, and other external applications or interfaces.

That means that the domain code must not have any outward-facing dependencies. Instead, with the help of the DIP, all dependencies point toward the domain code.

The following figure shows how such an architecture might look on an abstract level:

Figure 2.3: In a clean architecture, all dependencies point inward toward the domain logic. Source: "Clean Architecture" by Robert C. Martin

The layers in this architecture are wrapped around each other in concentric circles. The main rule in such an architecture is the dependency rule, which states that all dependencies between those layers must point inward...