Lerna 101

Basics of Lerna and Monorepo, presented at catch.com.au

Transcript

1. LERNA 101 @BLINKWALKER
2. LERNA 101 What’s A Monorepo? ▸ The repository contains more than one logical project ▸ These projects are most likely unrelated, loosely connected or can be connected by other means (via dependency) ▸ Google has one single Monstrous Monorepo with 9 millions unique source files.
3. LERNA 101 Why? @Catch/catch-live @Catch/search @Catch/notification @Catch/style-guide v1.0.0 @Catch/style-guide v2.0.0
4. LERNA 101 What do we have now - Cotd & Unity ▸ Large codebase with multiple modules / components ▸ Share resources within the big repo ▸ No package management per module ▸ No tagged version per module ▸ No independent installation
5. LERNA 101 What do we have now - Micro Services ▸ Smaller codebase ▸ Module has its own config ▸ Independent installation available ▸ Dedicated CI/CD ▸ Tagged version per module
6. LERNA 101 What’s Lerna? ▸ A tool for managing a javascript projects with multiple packages. ▸ Started by people behind Babel to manage more than 100 packages.
7. LERNA 101 Lerna CLI ▸ npm install lerna -g ▸ Lerna init ▸ Lerna bootstrap ▸ Lerna run ▸ Lerna publish
8. LERNA 101 Lerna modes ▸ Fixed / Locked mode (default) ▸ Independent mode: lerna init —independent
9. LERNA 101 Structure and Strategy ▸ Yarn handles deps ▸ Lerna handles tasks across 
 multiple packages ▸ One folder per package ▸ Build a generator so all packages have similar 
 structure ▸ Each package defines only its
 runtime deps ▸ Each package contains required
 own configurations, such as Babel, 
 eslint etc. But these configuration can be imported 
 from a shared location. ▸ All packages can have their own versions or 
 they can just have one big version in lerna.json
10. DEMO
11. LERNA 101 Benefits ▸ Manage multiple packages from high-level ▸ One place to manage CI/CD and release scripts ▸ One place to manage PR ▸ Bootstrap makes linking much easier ▸ Publish makes release much easier ▸ Changes and diff can be tracked easily across packages ▸ You can target single package with —scope ▸ Two modes to manage package versions ▸ Lerna import can absorb existing GitHub repos
12. LERNA 101 Any downside? ▸ One large repo is not friendly to new developers ▸ Bootstrap may take very long time for the first time and longer when it grows bigger ▸ Tests take long time to run if you don’t target a package ▸ Webpack needs to be configured carefully ▸ Who owns this repo?
13. LERNA 101 Who are using Lerna? ▸ Babel ▸ Create-react-app ▸ React-router ▸ Jest ▸ Storybook ▸ Vue-cli ▸ Many many more
14. LERNA 101 Resources ▸ Monorepos in the wild ▸ Monorepos in Git ▸ lerna.io ▸ Monorepo setup with Lerna
15. QUESTIONS?