Monorepo vs Multirepo

A comparison of the two approaches to code repository structure.

Transcript

1. Monorepo vs Multirepo Which is the superior approach? Jochen Lillich @geewiz • DrupalCamp Scotland 2019 1 / 28
2. Multirepo aka Manyrepo @geewiz • DrupalCamp Scotland 2019 2 / 28
3. Monorepo Centralisation Visibility Synchronisation Completeness Standardisation @geewiz • DrupalCamp Scotland 2019 3 / 28
4. Example SaaS product Web application API Client applications (iOS, Android) Shared libraries @geewiz • DrupalCamp Scotland 2019 4 / 28
5. About me Jochen Lillich Founder/CTO freistil.it freistilbox.com Managed Drupal Hosting @geewiz • DrupalCamp Scotland 2019 5 / 28
6. Monorepo users Google, Facebook, Twitter as well as Symfony, Laravel, Symplify, Shopsys, Contao, ... @geewiz • DrupalCamp Scotland 2019 6 / 28
7. Multirepo Management overhead Silos Dependency hell Complex cross-project changes @geewiz • DrupalCamp Scotland 2019 7 / 28
8. Monorepo Visibility Synchronisation Completeness Standardisation @geewiz • DrupalCamp Scotland 2019 8 / 28
9. Visibility Finding and discovering code Development in the open Code sharing Cross-pollination @geewiz • DrupalCamp Scotland 2019 9 / 28
10. Synchronisation Single history timeline Full-scope CI/CD Version-less dependency management Atomic cross-cutting changes @geewiz • DrupalCamp Scotland 2019 10 / 28
11. Dependency management From "pull" to "push": Pull Dependency Management: Consumer is responsible Push Dependency Management: Maintainer is responsible @geewiz • DrupalCamp Scotland 2019 11 / 28
12. You break it, you fix it. @geewiz • DrupalCamp Scotland 2019 12 / 28
13. Completeness No external dependencies No downloads No "download failed" @geewiz • DrupalCamp Scotland 2019 13 / 28
14. Standardisation Central issue tracking Common tooling Common practices (testing etc) Single CI integration Shared coding style guides @geewiz • DrupalCamp Scotland 2019 14 / 28
15. Strengths More transparency Easier access Less overhead Simplified workflows Faster feedback loops Higher code quality Improved application security @geewiz • DrupalCamp Scotland 2019 15 / 28
16. Weaknesses Volume of code Intimidating Long build times IDE lag Unclear ownership New tooling Broken master ! @geewiz • DrupalCamp Scotland 2019 16 / 28
17. Monorepo best practices Build everything from source for every change Have clear ownership Set a file size limit Avoid breaking changes Use feature flags Use only short-lived branches @geewiz • DrupalCamp Scotland 2019 17 / 28
18. Trunk Based Development "A source-control branching model, where developers collaborate on code in a single branch called ‘trunk’, resist any pressure to create other long-lived development branches by employing documented techniques. They therefore avoid merge hell, do not break the build, and live happily ever after." trunkbaseddevelopment.com @geewiz • DrupalCamp Scotland 2019 18 / 28
19. Build tools Bazel (Google, Asana, Braintree, Dropbox) Buck (Facebook) Lerna (Babel, Cloudflare, WP Gutenberg) monobuild symplify/monorepobuilder shopsys/monorepo-tools @geewiz • DrupalCamp Scotland 2019 19 / 28
20. Which approach should you choose? @geewiz • DrupalCamp Scotland 2019 20 / 28
21. Why not both? " @geewiz • DrupalCamp Scotland 2019 21 / 28
22. The "Splitrepo" hybrid A monorepo split into read-only project repositories Example: symfony/symfony splits into: symfony/console symfony/dom-crawler etc @geewiz • DrupalCamp Scotland 2019 22 / 28
23. Splitting a monorepo git subtree split git filter-branch Monorepo-specific tools, e.g. split.sh @geewiz • DrupalCamp Scotland 2019 23 / 28
24. Using git (lter-branch to split a monorepo @geewiz • DrupalCamp Scotland 2019 24 / 28
25. Learn more @geewiz • DrupalCamp Scotland 2019 25 / 28
26. Background Awesome Monorepo Monorepos in Git Monorepo: From Zero to Hero Advantages of Monolithic Version Control Monorepo? Please do! Why don't you have a monorepo? Advantages and Disadvantages of a Monolithic Codebase @geewiz • DrupalCamp Scotland 2019 26 / 28
27. Case studies "Why is Babel a monorepo?" "Monorepo to Multirepo and back again" "The Symfony Monolith Repository" "The Many Benefits of a Monorepo" @geewiz • DrupalCamp Scotland 2019 27 / 28
28. Thanks! Slides: http://bit.ly/monorepo-dcscot19 Feedback: @geewiz jochen@freistil.it @geewiz • DrupalCamp Scotland 2019 28 / 28