Managing monorepos with Lerna

Monorepos are useful but they are difficult to manage. Lerna is a tool to simplify your daily work with JS monorepos.

I gave this talk in the SevillaJS meetup. You can watch it in spanish in https://youtu.be/y8MGSdaPlS8.

Transcript

1. angelmm.rocks
2. @_angelmm UX Engineer at @bitnami Full stack developer that loves videogames and photography angelmm.rocks
3. What's a monorepo? A monorepo is a single repository that hosts more than one individual project
4. What's a monorepo? frontend backend library-1
5. What's a monorepo? frontend backend library-1
6. Who uses monorepos?
7. Who uses monorepos? "Facebook’s main source repository is enormous—many times larger than even the Linux kernel, which checked in at 17 million lines of code and 44,000 files in 2013." Facebook team
8. Who uses monorepos? 17 million of LOC 44000 files In 2013!
9. Why monorepos? • Single source of truth • Simplify the management of dependencies • Minify the issues with cross-project changes • Improve integration testing
10. Where's the poop? • Need specific tooling to work with it • High operation times • Tagging could be a mess • Large files • …
11. So, should I migrate all my code to a monorepo? Nope. Just use a monorepo when it makes sense for you. You can have several monorepos
12. Managing a JS monorepo github.com/bitnami/hex
13. HEx monorepo hex hex-core hex-js .git hex-docs
14. HEx challenges • Keep all the code in the same repo • Support several "compilation" pipelines • Manage cross-dependencies • Generate separate assets and packages • Versioning • Be able to add more packages in the future
15. HEx packages Project Dependencies Pipeline npm hex-core - gulp* yes hex hex-core gulp* yes hex-js - webpack yes hex-docs hex, hex-core gulp** nope
16. Lerna lernajs.io
17. Who is using lerna?
18. lerna init
19. lerna init
20. lerna init
21. Every package inside the packages folder is an independent project. All of them have their own package.json file lerna init
22. Resolve the dependencies of the projects, even the cross-projects dependencies lerna bootstrap
23. lerna bootstrap
24. Run npm scripts in your packages lerna run
25. lerna run start
26. lerna run --stream start
27. lerna run --parallel start
28. lerna run --stream --scope @bitnami/hex-js start
29. Check the changes you are going to deploy in the new version lerna diff && lerna updated
30. lerna updated
31. Let's publish the new awesome version of your projects lerna publish
32. lerna publish 1. Run ~lerna updated to get updated packages 2. Increment versions 3. Update dependencies 4. Create a commit and a tag 5. Publish the packages to npm
33. lerna publish
34. lerna publish
35. Publishing HEx hex hex-core hex-js
36. angelmm.rocks