Deploying on Ruby on Rails using Unicorn, PostgreSQL and Capistrano 3 for Ubuntu on DigitalOcean

DigitalOcean

Create a droplet and install the Ubuntu 16.04 system. Following that, login into your droplet using ssh:

$ ssh [email protected]

Fixing the irritating locale error.

Run the following commands:

$ nano /etc/environment

Add the lines below and save:

LANG=en_US.UTF-8
LC_ALL=en_US.UTF-8

Setting up user

$ sudo adduser deploy $ password deployer $ adduser deploy sudo

## Enabling SSH Authentication

$ ssh-add ~/.ssh/id_rsa

$ ssh-copy-id -i ~/.ssh/id_rsa.pub [email protected]

Now you can access to server:

$ ssh [email protected]

Installing Ruby

The first step is to install some dependencies for Ruby.

sudo apt-get update
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

Installing with rbenv is a simple two step process. First you install rbenv, and then ruby-build:

cd
git clone https://github.com/rbenv/rbenv.git ~/.rbenv
echo 'export PATH="$HOME/.rbenv/bin:$PATH"' >> ~/.bashrc
echo 'eval "$(rbenv init -)"' >> ~/.bashrc
exec $SHELL

git clone https://github.com/rbenv/ruby-build.git ~/.rbenv/plugins/ruby-build
echo 'export PATH="$HOME/.rbenv/plugins/ruby-build/bin:$PATH"' >> ~/.bashrc
exec $SHELL

rbenv install 2.3.1
rbenv global 2.3.1
ruby -v

Tell Rubygems not to install the documentation locally, and then install bundler

echo "gem: --no-ri --no-rdoc" > ~/.gemrc

gem install bundler

and run

rbenv rehash

after installing bundler.

Installing Nginx

sudo apt-get install nginx

So now we have Nginx installed, and we can start the Nginx webserver by using the service command:

sudo service nginx start

The service command also provides some other methods such as restart and stop that allow you to easily restart and stop your webserver.

PostgreSQL Database Setup

All you need to do in order to install PostgreSQL is to run the following command:

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

Next we need to setup our postgres user:

sudo su - postgres
createuser --your_user
exit

The password you type in here will be the one to put in your my_app/current/config/database.yml later when you deploy your app for the first time.

Capistrano Setup

The first step is to add Capistrano to your development group Gemfile:

group :development do
  gem 'capistrano', '~> 3.6', '>= 3.6.1'
  gem 'capistrano-rails', '~> 1.1', '>= 1.1.7'
  gem 'capistrano-rbenv', '~> 2.0', '>= 2.0.4'
end

After that, run bundle --binstubs and then cap install STAGES=production to generate your capistrano configuration.

Next we need to make some additions to our Capfile to include bundler, rails, and rbenv. Edit your Capfile and add these lines:

require "capistrano/setup"
require "capistrano/deploy"
require "capistrano/rbenv"
require 'capistrano/bundler'
require 'capistrano/rails'

Now we can configure the config/deploy.rb to setup our general configuration for our app. Edit that file and make it like the following replacing "myapp" with the name of your application and git repository:

set :application, 'myapp'

set :repo_url, "[email protected]:myapp.git"

set :deploy_to, '/var/www/myapp'

set :unicorn_pid, "#{deploy_to}/shared/pids/unicorn.pid"

set :unicorn_config, "#{current_path}/config/unicorn.rb"

set :unicorn_binary, "unicorn"

append :linked_files, 'config/database.yml', 'config/secrets.yml'

append :linked_dirs, 'log', 'tmp/pids', 'tmp/cache', 'tmp/sockets', 'public/system'

namespace :unicorn do
  desc 'Stop Unicorn'
  task :stop do
    on roles(:app) do
      if test("[ -f #{fetch(:unicorn_pid)} ]")
        execute :kill, capture(:cat, fetch(:unicorn_pid))
      end
    end
  end

  desc 'Start Unicorn'
  task :start do
    on roles(:app) do
      within current_path do
        with rails_env: fetch(:rails_env) do
          execute :bundle, "exec unicorn -c #{fetch(:unicorn_config)} -D"
        end
      end
    end
  end

  desc 'Reload Unicorn without killing master process'
  task :reload do
    on roles(:app) do
      if test("[ -f #{fetch(:unicorn_pid)} ]")
        execute :kill, '-s USR2', capture(:cat, fetch(:unicorn_pid))
      else
        error 'Unicorn process not running'
      end
    end
  end

  desc 'Restart Unicorn'
  task :restart
  before :restart, :stop
  before :restart, :start
end

after "deploy:cleanup", "unicorn:restart"

Unicorn namespace need to do in order for restart unicorn server after deploy automatically, or we can do this with a special command:

$ cap production unicorn:restart
$ cap production unicorn:start
$ cap production unicorn:stop

Now we need to edit our config/deploy/production.rb

set stage: :production

server 'xxx.xxx.xxx.xx', user: 'deploy', roles: %w{web app db}

set :rbenv_ruby, '2.3.1'

set :rbenv_type, :user

Replace xxx.xxx.xxx.xx with your server's IP address and set your actual ruby version for rbenv_ruby option.