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Development Dependencies Install

This guide covers how to set up an environment for Ruby on Rails core development.

After reading this guide, you will know:

How to set up your machine for Rails development

The Easy Way

The easiest and recommended way to get a development environment ready to hack is to use the Rails development box.

The Hard Way

In case you can't use the Rails development box, see the steps below to manually build a development box for Ruby on Rails core development.

Install Git

Ruby on Rails uses Git for source code control. The Git homepage has installation instructions. There are a variety of resources on the net that will help you get familiar with Git:

Try Git course is an interactive course that will teach you the basics.
The official Documentation is pretty comprehensive and also contains some videos with the basics of Git.
Everyday Git will teach you just enough about Git to get by.
GitHub offers links to a variety of Git resources.
Pro Git is an entire book about Git with a Creative Commons license.

Clone the Ruby on Rails Repository

Navigate to the folder where you want the Ruby on Rails source code (it will create its own rails subdirectory) and run:

$ git clone https://github.com/rails/rails.git
$ cd rails

Install Additional Tools and Services

Some Rails tests depend on additional tools that you need to install before running those specific tests.

Here's the list of each gems' additional dependencies:

Action Cable depends on Redis
Active Record depends on SQLite3, MySQL and PostgreSQL
Active Storage depends on Yarn (additionally Yarn depends on Node.js), ImageMagick, FFmpeg, muPDF, and on macOS also XQuartz and Poppler.
Active Support depends on memcached and Redis
Railties depend on a JavaScript runtime environment, such as having Node.js installed.

Install all the services you need to properly test the full gem you'll be making changes to.

NOTE: Redis' documentation discourage installations with package managers as those are usually outdated. Installing from source and bringing the server up is straight forward and well documented on Redis' documentation.

NOTE: Active Record tests must pass for at least MySQL, PostgreSQL, and SQLite3. Subtle differences between the various adapters have been behind the rejection of many patches that looked OK when tested only against single adapter.

Below you can find instructions on how to install all of the additional tools for different OSes.

macOS

On macOS you can use Homebrew to install all of the additional tools.

To install all run:

$ brew bundle

You'll also need to start each of the installed services. To list all available services run:

$ brew services list

You can then start each of the services one by one like this:

$ brew services start mysql

Replace mysql with the name of the service you want to start.

Ubuntu

To install all run:

$ sudo apt-get update
$ sudo apt-get install sqlite3 libsqlite3-dev mysql-server libmysqlclient-dev postgresql postgresql-client postgresql-contrib libpq-dev redis-server memcached imagemagick ffmpeg mupdf mupdf-tools libxml2-dev

# Install Yarn
$ curl -sS https://dl.yarnpkg.com/debian/pubkey.gpg | sudo apt-key add -
$ echo "deb https://dl.yarnpkg.com/debian/ stable main" | sudo tee /etc/apt/sources.list.d/yarn.list
$ sudo apt-get install yarn

Fedora or CentOS

To install all run:

$ sudo dnf install sqlite-devel sqlite-libs mysql-server mysql-devel postgresql-server postgresql-devel redis memcached imagemagick ffmpeg mupdf libxml2-devel

# Install Yarn
# Use this command if you do not have Node.js installed
$ curl --silent --location https://rpm.nodesource.com/setup_8.x | sudo bash -
# If you have Node.js installed, use this command instead
$ curl --silent --location https://dl.yarnpkg.com/rpm/yarn.repo | sudo tee /etc/yum.repos.d/yarn.repo
$ sudo dnf install yarn

Arch Linux

To install all run:

$ sudo pacman -S sqlite mariadb libmariadbclient mariadb-clients postgresql postgresql-libs redis memcached imagemagick ffmpeg mupdf mupdf-tools poppler yarn libxml2
$ sudo mariadb-install-db --user=mysql --basedir=/usr --datadir=/var/lib/mysql
$ sudo systemctl start redis mariadb memcached

NOTE: If you are running Arch Linux, MySQL isn't supported anymore so you will need to use MariaDB instead (see this announcement).

FreeBSD

To install all run:

$ pkg install sqlite3 mysql80-client mysql80-server postgresql11-client postgresql11-server memcached imagemagick ffmpeg mupdf yarn libxml2
# portmaster databases/redis

Or install everything through ports (these packages are located under the databases folder).

NOTE: If you run into troubles during the installation of MySQL, please see the MySQL documentation.

Database Configuration

There are couple of additional steps required to configure database engines required for running Active Record tests.

In order to be able to run the test suite against MySQL you need to create a user named rails with privileges on the test databases:

$ mysql -uroot -p

mysql> CREATE USER 'rails'@'localhost';
mysql> GRANT ALL PRIVILEGES ON activerecord_unittest.*
       to 'rails'@'localhost';
mysql> GRANT ALL PRIVILEGES ON activerecord_unittest2.*
       to 'rails'@'localhost';
mysql> GRANT ALL PRIVILEGES ON inexistent_activerecord_unittest.*
       to 'rails'@'localhost';

PostgreSQL's authentication works differently. To set up the development environment with your development account, on Linux or BSD, you just have to run:

$ sudo -u postgres createuser --superuser $USER

and for macOS:

$ createuser --superuser $USER

Then, you need to create the test databases for both MySQL and PostgreSQL with:

$ cd activerecord
$ bundle exec rake db:create

NOTE: You'll see the following warning (or localized warning) during activating HStore extension in PostgreSQL 9.1.x or earlier: "WARNING: => is deprecated as an operator".

You can also create test databases for each database engine separately:

$ cd activerecord
$ bundle exec rake db:mysql:build
$ bundle exec rake db:postgresql:build

and you can drop the databases using:

$ cd activerecord
$ bundle exec rake db:drop

NOTE: Using the Rake task to create the test databases ensures they have the correct character set and collation.

If you're using another database, check the file activerecord/test/config.yml or activerecord/test/config.example.yml for default connection information. You can edit activerecord/test/config.yml to provide different credentials on your machine if you must, but obviously you should not push any such changes back to Rails.

Install JavaScript dependencies

If you installed Yarn, you will need to install the javascript dependencies:

$ yarn install

Install Bundler gem

Get a recent version of Bundler

$ gem install bundler
$ gem update bundler

and run:

$ bundle install

or:

$ bundle install --without db

if you don't need to run Active Record tests.

Contribute to Rails

After you've set up everything, read how you can start contributing.