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https://github.com/beberlei/composer-monorepo-plugin

Integrates Composer into monolithic repositories with many packages.
https://github.com/beberlei/composer-monorepo-plugin

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Integrates Composer into monolithic repositories with many packages.

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README

        

# Composer Monorepo Plugin

Note: this project is still experimental. Please provide feedback!

This plugin adds support for Monorepos when using Composer package manager. It
introduces a maintainable approach to managing dependencies for multiple
packages in a single repository, without losing the benefits of having explicit
dependencies for each separate package.

Repositories managed with this plugin contain two kinds of packages:

1. Composer packages defined by a single global `composer.json` with all external dependencies at the root of the repository.
2. Many monorepo packages in sub-folders of the project, each with its own
`monorepo.json`, a simplified `composer.json` file.

Dependencies in monorepos can be either a third party Composer package that
is listed in the ``composer.json`` or a monorepo package contained in the project.

This plugins build step generates autoloaders with `vendor/autoload.php` files for
each package with access to the explicitly specified dependencies only.

The following steps are performed by this plugin when building the autoloads:

1. It detects `monorepo.json` files in subdirectories excluding `vendor/` and marks
them as roots of packages.
2. It then fetches all composer packages from the locally installed packages.
3. Finally for each package with `monorepo.json` it generates a
`vendor/autoload.php` file using all the dependencies defined in that
package from either other monorepo packages or regular Composer packages.

This plugin draws inspiration from Google [Blaze/Bazel](http://bazel.io/) and
Facebook [Buck](http://facebook.github.io/buck/) implementing a single
monolithic repository for whole projects/company. It's the missing piece for
the monolithic repository workflow using PHP and Composer.

More details about reasoning on Gregory Szorc's blog:

- [On Monlithic Repositories](http://gregoryszorc.com/blog/2014/09/09/on-monolithic-repositories/)
- [Notes from Facebooks Developer Infrastructure at Scale F8 talk](http://gregoryszorc.com/blog/2015/03/28/notes-from-facebook's-developer-infrastructure-at-scale-f8-talk/)

## Backwards Incompatible Changes in v0.12

In v0.12 we removed the `fiddler` script and the possibility to build a PHAR archive.
This project is now a first-class composer plugin only and requires Composer v1.1+
for the `composer monorepo:` commands to be available.

The `fiddler.json` files must be renamed to `monorepo.json`.

Use v0.11.6 or lower if you don't want to break this in your project yet.

## Installation

Add the composer monorepo plugin to your root composer.json with:

$ composer require beberlei/composer-monorepo-plugin

It will be automatically added as a Composer plugin.

## Usage

Whenever Composer generates autoload files (during install, update or
dump-autoload) it will find all sub-directories with `monorepo.json` files and
generate sub-package autoloaders for them.

You can execute the autoload generation step for just the subpackages by
calling:

$ composer monorepo:build

You create a `composer.json` file in the root of your project and use
this single source of vendor libraries across all of your own packages.

This sounds counter-intuitive to the Composer approach at first, but
it simplifies dependency management for a big project massively. Usually
if you are using a composer.json per package, you have mass update sprees
where you upate some basic library like "symfony/dependency-injection" in
10-20 packages or worse, have massively out of date packages and
many different versions everywhere.

Then, each of your own package contains a `monorepo.json` using almost
the same syntax as Composer:

{
"deps": [
"components/Foo",
"vendor/symfony/symfony"
],
"autoload": {
"psr-0": {"Foo\\": "src/"}
}
}

You can then run `composer dump-autoload` in the root directory next to
composer.json and this plugin will detect all packages, generate a custom
autoloader for each one by simulating `composer dump-autoload` as if a
composer.json were present in the subdirectory.

This plugin will resolve all dependencies (without version constraints, because it
is assumed the code is present in the correct versions in a monolithic
repository).

Package names in `deps` are the relative directory names from the project root,
*not* Composer package names.

You can just `require "vendor/autoload.php;` in every package as if you were using Composer.
Only autoloads from the `monorepo.json` are included, which means all dependencies must be explicitly
specified.

## Configuration Schema monorepo.json

For each package in your monolithic repository you have to add `monorepo.json`
that borrows from `composer.json` format. The following keys are usable:

- `autoload` - configures the autoload settings for the current package classes and files.
- `autoload-dev` - configures dev autoload requirements. Currently *always* evalauted.
- `deps` - configures the required dependencies in an array (no key-value pairs with versions)
using the relative path to the project root directory as a package name.
- `deps-dev` - configures the required dev dependencies
- `replace` - configures the packages's replacements.

## Git Integration for Builds

In a monorepo, for every git commit range you want to know which components changed.
You can test with the `git-changed?` command:

```bash
composer monorepo:git-changed? components/foo $TRAVIS_COMMIT_RANGE
if [ $? -eq 0 ]; then ant build fi
```