Enforcing Architecture in Legacy Systems

1. Enforcing Architecture in Legacy Systems @rweisleder.de roland.weisleder@arcndev.com
2. Whoever wishes to build high towers must spend much time near the foundation. Anton Bruckner
3. Source: https://unsplash.com/photos/AF36q06J8fQ
4. Source: https://xkcd.com/2347/
5. Source: https://www.monkeyuser.com/2019/v-201/
6. Source: https://unsplash.com/photos/snNHKZ-mGfE
7. Compatibility Portability Maintainability Security Performance effiency Reliability Usability Functional suitability Evolution Value Chain Genesis Custom Built Product Commodity visible invisible Based on: https://www.innoq.com/en/blog/quality-value-chain-evolution/
8. Challenge: Architecture Code Gap { }
9. Architecture Tests as Guardrails • Make architecture explicit • Prevent architectural erosion • Guide continuous change
10. Demo
11. Enforcing Architecture Stepwise Technical Architecture • Naming conventions • Layered architecture • Framework boundaries • Dependency rules Domain Architecture • Module boundaries • Dependency directions • Cycle prevention • Public APIs Cross-Cutting Concerns Security Transaction Auditing Observability
12. Best Practices in Legacy Systems • Start with the thing that causes the most issues • Use freezing if you can’t fix it immediately • Resolve violations stepwise
13. Challenge: Architecture Code Gap { } Easy to use in legacy projects ☺
14. https://github.com/rweisleder/archunit-spring
15. With ArchUnit, the Leaning Tower of Pisa would not have happened. Some AI trying to summarize this talk
16. Testing can detect only the presence of errors, not their absence.
17. Enforcing Architecture in Legacy Systems Code github.com/rweisleder/archunit-spring github.com/rweisleder/archunit-talk-examples github.com/TNG/ArchUnit-Examples Docs archunit.org archunitnet.readthedocs.io ts-arch.github.io/ts-arch/ pypi.org/project/PyTestArch/ Slides speakerdeck.com/rweisleder Need help with your Legacy Code? Contact me! roland.weisleder@arcndev.com in/roland-weisleder @rweisleder.de