[DevoxxFR 2023] Hexagonal Architecture in 15 Minutes: Simplifying Complex Systems
Introduction
Julien Topçu, a tech lead at LesFurets, delivers a concise yet powerful Devoxx France 2023 quickie titled “L’architecture hexagonale en 15 minutes.” In this 17-minute talk, Topçu introduces hexagonal architecture (also known as ports and adapters) as a solution for building maintainable, testable systems. Drawing from his experience at LesFurets, a French insurance comparison platform, he provides a practical guide for developers navigating complex codebases.
Key Insights
Topçu explains hexagonal architecture as a way to decouple business logic from external systems, like databases or APIs. At LesFurets, where rapid feature delivery is critical, this approach reduced technical debt and improved testing. The architecture organizes code into:
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Core Business Logic: Pure functions or classes that handle the application’s rules.
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Ports: Interfaces defining interactions with the outside world.
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Adapters: Implementations of ports, such as database connectors or HTTP clients.
Topçu shares a refactoring example, where a tightly coupled insurance quote system was restructured. By isolating business rules in a core module, the team simplified unit testing and swapped out a legacy database without changing the core logic. He highlights tools like Java’s interfaces and Spring’s dependency injection to implement ports and adapters efficiently. The talk also addresses trade-offs, such as the initial overhead of defining ports, balanced by long-term flexibility.
Lessons Learned
Topçu’s insights are actionable:
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Decouple Early: Separating business logic prevents future refactoring pain.
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Testability First: Hexagonal architecture enables comprehensive unit tests without mocks.
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Start Small: Apply the pattern incrementally to avoid overwhelming teams.
These lessons resonate with developers maintaining evolving systems or adopting Domain-Driven Design. Topçu’s clear explanations make hexagonal architecture accessible even to newcomers.
Conclusion
Julien Topçu’s quickie offers a masterclass in hexagonal architecture, proving its value in real-world applications. His LesFurets example shows how to build systems that are robust yet adaptable. This talk is essential for developers aiming to create clean, maintainable codebases.