Monorepos in the Wild

Managing multi-package Node.js projects using a Monorepo approach and Lerna

Transcript

1. Managing multi-package Node.js projects using a Monorepo approach and Lerna Monorepos in the Wild
2. About me • (Frontend) Web Developer @ karriere.at • Web Tinkerer @ github.com/maoberlehner (node-sass-magic-importer, avalanche,…) • Blogger @ markus.oberlehner.net 13.01.18 2
3. What is a Monorepo? 13.01.18 3
4. Multiple projects in a single repository • A single repository containing the code of multiple projects • Projects may or may not be related • Projects can be dependents of each other (e.g. React and react-dom) 13.01.18 4
5. Examples for Monorepos • The code of a website, apps and an API in a single repository • All the code and assets of a (tech) company in a single repository • The core functionality and related components in a single repository 13.01.18 5
6. Isn‘t that a horrible idea? 13.01.18 6
7. Not necessarily (if you’re doing it right) 13.01.18 7
8. Modern-day software development • Package managers • Micro services • Modularization 13.01.18 8
9. Modular code & monolithic source control • Modular open source projects are using Monorepos • Micro services based infrastructures are built using Monorepos 13.01.18 9
10. The best of two worlds • Modular code is easier to share and reuse • Code in a single repository is easier to maintain and refactor • Monolithic source control != tightly coupled code • Code in a Monorepo can be modular and maintainable 13.01.18 10
11. Pros & cons of Monorepos 13.01.18 11
12. Cons • Increased codebase complexity • Potential scaling problems • Harder to implement access control • Potential build and test bloat 13.01.18 12
13. Pros • One source of truth • Extensive code sharing and reusing • Large scale refactoring made easy • Easier collaboration across teams 13.01.18 13
14. Two types of Monorepos 13.01.18 14
15. Monstrous Monorepos • All the code of a (tech) company is stored in a single repository • Twitter: Git fork, several GB • Facebook: Mercurial, over 50GB • Google: Piper, Clients in the Cloud, over 90TB 13.01.18 15
16. Project Monorepos • The core functionality and optional components in a single repository • Components may depend on each other • Examples: React, Babel, Ember, Symfony,… 13.01.18 16
17. Babel • 100+ components managed in one Monorepo • Uses Lerna to manage the multi-package repository • Fixed versions, all packages have the same version number • Packaging via NPM 13.01.18 17
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19. Symfony • 30+ components managed in one Monorepo • Combination of Monorepo and Manyrepo approach • Automatic generation of read-only Manyrepos with splitsh • Packaging via Composer 13.01.18 19
20. From Manyrepos to Monorepo 13.01.18 20
21. Modular SASS framework avalanche • 40+ NPM packages / 40+ GitHub repositories • Major refactoring would have been very hard to do • Tooling (linting, testing,…) repeated in every repository 13.01.18 21
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24. Working with Lerna 13.01.18 24
25. Configuring Lerna 13.01.18 25
26. Importing Git repositories • Merge existing repositories into a Monorepo • Keep commit history 13.01.18 26
27. Basic Lerna workflow 13.01.18 27 • Install (cross) dependencies • Publish new releases of (modified) packages
28. Recap 13.01.18 28
29. Summary • Monolithic source control != monolithic software • Two types of Monorepos • Tools: splitsh, Lerna 13.01.18 29
30. 13.01.18 30 Thank You. Markus Oberlehner Web Developer https://markus.oberlehner.at https://github.com/maoberlehner https://twitter.com/maoberlehner