Johannes Brüderl Lead Software Engineer – E.ON SE Johannes is a Software Engineer for life. He enjoys working on distributed systems and open source products. His preferred tech-stack at this time includes Kubernetes, Apache Kafka and Go. Currently he is working in the IoT Area and leads the development of E.ON’s global IoT Platform to serve E.ON’s products. He is also an active open source contributor and enjoys fixing bugs & writing enhancements for upstream open source projects.

1. Mono-Repo and
Microservices - a
contradiction?
Johannes Bruederl - Software Engineer
github.com/birdayz

2. Who is this guy?
- Programmer for life, <3 Go
- <3 Open Source
- Distributed Systems
- <3 k8s, Kafka
- Currently active in the IoT Area

3. What we will cover
- We talk about repository setups
- Focus on Microservices
- Pro/Con
- Tooling recommendations

4. This topic is
super controversial

5. Kinds of Repositories
- Multi-repo
- Organization Monorepo
- Project Monorepo
- Anything between those
- Don’t be dogmatic

6. Multi-Repo
- Repo per service
- Self-contained services
- Infrastructure as Code
- Consider overarching infrastructure
- Templates
- Automated PRs & Cleanup processes

7. Many repos...

8. The Project Mono-Repo
- Multiple applications/libraries
- Related code, or not
- Many commits & committers
- Build extensive tooling around repo
- Everything is versioned together in lock-step

9. Example: Babel

10. The conflict with Microservices
- Monoliths favor Mono-Repos
- Microservices strive for separation
- Cost of additional Repo
- Smaller services favor Mono-Repo
- Microservices vs Nanoservices vs Serverless

11. Sharing Code
- Breaking services you don’t even know about
- Anxiety to make changes
- Large changesets: It’s a hassle
- Avoid friction
- Avoid silos

12. Refactoring
- Frequent refactoring
- Do it faster
- Immediate feedback
- Confidence in large changesets
- Simplify updating APIs

13. Visibility & Discoverability
- Cloning many repos
- Pull request across multiple packages
- Exploring the codebase
- Access control problematic

14. Building tools around the Repo
- More complex
- Build duration
- Idempotent builds
- Governance
- Use task runners
- Version the scripts

15. TL;DR
- Faster changes
- Safer changnes
- Visibility
- More effort for DevOps
- Superior Developer UX
- Easier style standardization

16. Some tools
- Build tools
- Java: https://github.com/GoogleContainerTools/jib
- Go: Idempotent & fast builds by default
- Buck https://github.com/facebook/buck
- Bazel https://bazel.build/
- Task Runner:
- https://taskfile.org/
- https://magefile.org/
- Make
- Lerna: https://lernajs.io/

17. Thank you!