After you set up your server, its time to deploy applications into it. One of the most popular web application frameworks is Ruby on Rails. This is built using the Ruby programming language and it enables developers to create web applications ranging from quick prototypes and Minimum Viable Products (MVPs) up to large distributed applications. Rails is an opinionated framework, meaning there is a standard way of doing things, but it can also be modified to suit your preferred architecture and coding style. By default however, Rails provides sensible and secure defaults that will help you run and deploy your applications quickly. Through using Ruby gems to augment functionality, you can create a fully-functional web application in a short amount of time.

We will start the process by setting up the dependencies needed for Ruby on Rails.

(Updated March 2018)

Install Git

Git is perhaps the most popular version control system today. By utilizing small functions and commands that do only one task (and does it well), it achieves tremendous flexibility and power.

Git is basically a command-line tool, however there are several graphical user interfaces (GUIs) built that support all major operating systems. A sample list can be found at https://git-scm.com/downloads/guis.

If you are using Ubuntu or any other Linux distribution, you can install git using the default package manager:

sudo apt-get install git

It is useful to specify global parameters in git, like your name and email address so that you do not need to specify it whenever you push to your repository.

git config --global user.name "Juan dela Cruz"
git config --global user.email "[email protected]"

To list the git configurations in your system:

git config --list

Install Ruby

Ruby is a programming language designed for developer happiness. It provides an elegant syntax that makes programming enjoyable. As Ruby on Rails is built on Ruby, we need to install Ruby itself in the system.

First we need to install the dependencies needed to compile and install Ruby. If you are using Ubuntu, this is as simple as the below command (other operating systems will have their equivalent packages):

sudo apt-get install git-core curl zlib1g-dev build-essential libssl-dev libreadline-dev libyaml-dev libsqlite3-dev sqlite3 libxml2-dev libxslt1-dev libcurl4-openssl-dev python-software-properties libffi-dev

If you plan on using ImageMagick for image processing in your application, like if you have a photo upload feature that requires the image to be resized, you also need to install these dependencies:

sudo apt-get install imagemagick libmagickwand-dev

Managing Ruby versions

There are times when you need to run applications using different Ruby versions. In this case it is important to properly manage the Ruby versions installed in your system. Two of the most popular version managers are RVM and rbenv. As these two work essentialy the same, it is up to you which one you should choose to use. There are arguments that RVM muddles more on your system than rbenv, although personally I have used both in my projects and they both work quite well.

In this article we will use rbenv as our Ruby version manager. If you opt to use RVM instead, their website includes a tutorial on how to install RVM.

Basically we will fetch a predefined install script from the git repository and run that script in our system. Security-aware individuals may cringe at this method, but at the moment this is the simplest and quickest way to install programs.

git clone https://github.com/rbenv/rbenv.git ~/.rbenv

echo 'export PATH="$HOME/.rbenv/bin:$PATH"' >> ~/.bashrc

echo 'eval "$(rbenv init -)"' >> ~/.bashrc
exec $SHELL

Then we install the script that makes it easy to build, compile and install Ruby:

mkdir -p "$(rbenv root)"/plugins

git clone https://github.com/rbenv/ruby-build.git "$(rbenv root)"/plugins/ruby-build

Once that is all set, we are now ready to install Ruby using rbenv:

rbenv install --list

rbenv install -v 2.4.3
rbenv global 2.4.3

Just replace the version number with the Ruby version you want to install. You can also install Ruby from source but take note that doing this will install Ruby in your local system and will not be managed in rbenv.

Install Bundler and Rails

When you installed Ruby, the package manager called Rubygems is also installed by default. Rubygems lets you install Ruby libraries called gems that provide specific functionality that you can include in your application. Ruby on Rails, the application framework that we will use, is also packaged as a gem. Ruby Toolbox is an awesome tool to find gems depending on your desired usage, and ranks it by popularity or activity.

When installing Ruby gems, the documentation is also installed by default. While there are cases when this local documentation is useful, most of the time you can refer to the internet for the documentation when you need it. You can opt not to include the gem documentation when you install gems and this will make the install faster and will consume less disk space.

To exclude the documentation when installing gems, use this command:

gem install rails --no-rdoc --no-ri

As typing this whenever you install gems can be tedious, you can also make this as the system default. Add the –no-document flag to your gemrc file:

echo "gem: --no-document" > ~/.gemrc

Make sure that Rubygems is updated to the latest stable version:

gem update --system

Now we are ready to install Bundler and Rails

gem install bundler
gem install rails

Bundler makes it easy to manage gems in your application using a configuration file called a Gemfile where you specify which gems and versions your application uses.

After installing new gems, we need to tell rbenv to use the latest binaries/executables that are included in the new installs.

rbenv rehash

Install a Javascript runtime library

Ruby on Rails’ asset pipeline requires a Javascript runtime library to be installed as well. Therubyracer is a Ruby gem that you can use for this purpose, however, the gem’s size can be an issue.

I recommend installing NodeJS and use it as the runtime library. You can install it from source from their home page, or you can use Ubuntu’s package manager to install it for you:

Add the NodeJS repository so Ubuntu can fetch it:

curl -sL https://deb.nodesource.com/setup | sudo bash -
sudo apt-get update
sudo apt-get install nodejs

Set up the database

A fully-functional web application needs a database to run. There are many free and available databases available and you should pick one that suits your needs. Relational databases like MySQL and PostgreSQL and document-oriented databases like MongoDB are some of the most popular choices.

In this article we will set up either MySQL or PostgreSQL.

Install MySQL

In Ubuntu, its pretty straightforward to install MySQL:

sudo apt-get install mysql-server

During the installation process, it will ask for the root password. Take note of this root password as you will need it to set up your application later on.

The configuration file is located at:

/etc/mysql/my.cnf

By default no configuration is needed and the MySQL service should be up and running. If you edited the configuration file or just need to restart the service in case of an issue:

sudo service mysql restart

In case you misplaced the root password, you can re-set the password using this command:

sudo dpkg-reconfigure mysql-server-5.5

Just replace the version number with the one installed in your system.

Install PostgreSQL

In Ubuntu, install the following packages:

sudo apt-get install postgresql postgresql-contrib libpq-dev

During the installation process, it will set up a default user called postgres. We will use this default user to create the database user we will use in our applications. In this example, we will create the pguser user.

sudo -u postgres createuser -s pguser

We then change the password of pguser using the PostgreSQL console:

sudo -u postgres psql

Inside the console, type the following commands:

\password pguser
...
(change password prompt)
...

While we are in the console, we can also create the PostgreSQL database that our application will use, and set the pguser user as the database owner so we get full access:

CREATE DATABASE webapp_development OWNER pguser;
\q

Create a new Rails application

Now that we have Ruby and a database installed, we can now create our Rails application. Let’s start by calling Rails’ new command to set up our application (called “awesomeapp” in this example).

rails new awesomeapp

Rails will automatically generate files inside the “awesomeapp” folder that contains everything necessary to run your application. It will also try to run bundle install and install the default Ruby gems set by Rails.

Open the Gemfile in the application folder and add the database wrapper gem that you need to use:

source 'https://rubygems.org'

gem 'rails', '4.2.4'
# If you are using MySQL
gem 'mysql2'
# If you are using PostgreSQL
gem 'pg'
# If you are using MongoDB
gem 'mongoid'
gem 'bson_ext'

...(your other gems below)...

After changing the Gemfile, install the new gems by running:

bundle install

We then need to set the database connection for our application by editing config/database.yml. The configuration will differ depending on which database you are using. If you are using MySQL:

development:
  adapter: mysql2
  database: awesomeapp_development
  username: root
  password: rootpassword
  host: localhost
  socket: /var/run/mysqld/mysqld.sock

If you are using PostgreSQL:

development:
  adapter: postgresql
  encoding: unicode
  host: localhost
  username: pguser
  password: pguserpassword
  database: awesomeapp_development
  pool: 5

We can now run our (empty) application using this command:

rails s

This command will spin up a local web server (Webrick by default) and run your application on port 3000. To visit your application using a browser, go to this URL:

http://localhost:3000

If you are using MySQL and encounter this error when accessing the above URL:

Specified 'mysql2' for database adapter, but the gem is not loaded. Add `gem 'mysql2'` to your Gemfile (and ensure its version is at the minimum required by ActiveRecord).

This is a known issue between the mysql2 gem and Rails, and you can solve it by using an older version of the mysql2 gem in your Gemfile:

gem 'rails', '4.2.4'
gem 'mysql2', '0.3.20'

If everything goes well, you will see this message in your browser:

Congratulations! You have successfully installed Ruby on Rails in your system and ready to create that awesome app!