Strategic Design with Monorepos
What is a monorepo?
Monorepo —
a single repository holding the code of multiple projects which may or may not be related in some way
In some cases the monorepo contains nearly all of the projects in a given organization
Colossal
- All modules in one place
- Versioned centrally
- Dependencies managed
Project
- Entire application stack
- GraphQL + Web + Native + Shared
- Test / Build / Deploy together
Micro Platform
Why Monorepos?
+1 buzzword 😏
So how to:
- feel safe and confident putting new changes/features
- help more people more easily collaborate on one project
How easy is it to:
- get started
- submit changes
- test
- deploy
- identify faults
- revert
Polyrepo
+ Flexibility
+ Encapsulating complexity
+ Easy to deploy
+ Clear ownership and politics
- Scattered developer env
- Complex lint / test / build / release
- Cross repo changes hard
- Cross repo rollbacks terrifying
- Difficulty enforcing conventions
- Context loss
Monorepo Advantages
Developer environment
+ Every service in one place
+ Backend, Frontend, DB
+ Top level yarn && yarn start
Common configuration
+ Top level ESLint / Prettier / Babel etc.
+ Reduce convention switching
+ No orphaned packages
Code reuse
+ Can split common code into modules
+ Use and dependencies versioned
+ Breaking changes visible
Cross project changes
+ 1 PR for multi module features
+ 1 PR to review with full context
+ 1 PR to revert if it goes wrong
Single release process
+ Everything needed to build available
+ Everything needed to test available
+ Release / Revert with confidence
Single culture
“Software is Easy, People are Hard”
Polyrepo
+ Flexibility
+ Encapsulating complexity
+ Easy to deploy
+ Clear ownership and politics
- Scattered developer env
- Complex lint / test / build / release
- Cross repo changes hard
- Cross repo rollbacks terrifying
- Difficulty enforcing conventions
- Context loss
Monorepo
+ Unified developer environment
+ Single lint / test / build / release
+ Cross module changes
+ Cross module rollbacks
+ Code reuse / sharing
+ Shared culture
Why NOT?
Monorepo Disadvantages
- the repo will be bigger — more code to handle
- CI / CD pipeline
- less mature tooling
- fewer stackoverflow posts
- organizations
How do I get Monorepo?
How do we
- manage dependencies
- version, test, build a whole repo
- continually integrate / deploy
- manages dependencies
- eliminates redundancy
- exposes current co-packages
- single yarn install and go
- manages testing
- manages versioning
- manages building
- manages releasing
- used by plenty of projects
Structure of the project
"first" package
"app"
package.json
package.json
Adding lerna
lerna.json
Nx
First-class support
nx dep-graph
