All You Always Wanted to Know About Monorepo But Were Afraid To Ask

2019-10-28

What is Monorepo?

A repository that contains multiple packages or projects. Those projects can, but don't have to be related. Most famous monorepo pioneers are Google, Facebook and Twitter.

The most famous monorepos in PHP are Symfony, Laravel, Symplify, Sylius, Yii2 or Shopsys.

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Monorepo vs. Multirepo

Single-repo or split-repo?

Monorepo is split into many single-repos, e.g. Symfony/Symfony is split into Symfony/Console, Symfony/Validator etc. Each single-repo repository is read-only. You can change its code via pull-request to the monorepo.

Many-repo

The other approach to manage multiple repositories. 1 package = 1 own repository. Each package has it's own development, tagging and even maintainers. E.g. Doctrine 2 or Nette 2.

Monolith

Monolith ≠ monorepo. Monolith is huge amount of coupled code of 1 application that is hell to maintain.

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Why is Monorepo so Awesome?

• Simplified organization

• Easy to coordinate changes across modules.

• Simplified dependencies

• Single lint, build, test and release process

• Tooling

• Single place to report issues

• Cross-project changes

• Tests across modules are run together → finds bugs that touch multiple modules easier

These are cherry-picked reasons from legendary Advantages of Monolithic Version Control. Read it to get deeper insight.

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Tools that make using Monorepo Easy

• Symplify/MonorepoBuilder - simpler, written in PHP

  • init, setup and auto-split monorepo in minutes - great for start from scratch

• shopsys/monorepo-tools - advanced, shell scripts

  • init, setup and auto-split monorepo in minutes - great for start from scratch
  • merges history of multiple repos to one and more - great for start for code with many repositories with long history

What to Read Next?

• Why Google stores billions of lines of code in a single repository (2016)
• Monorepos in Git (2015)
• korfuri/awesome-monorepo