DigitalOcean Ubuntu 18.04 x64 + Rails 5 + Nginx + Unicorn + PostgreSQL9.6 + Capistrano 3

### DigitalOcean Ubuntu 18.04 x64 + Rails 5 + Nginx + Unicorn + PostgreSQL9.6 + Capistrano 3

SSH into Root

    $ ssh [email protected]

Change Root Password

    $ passwd

Add Deploy User

    $ adduser deployer
    $ sudo chown deployer:deployer /var/www/

Update Sudo Privileges

    $ visudo
    username ALL=(ALL:ALL) ALL
    
Generate public key
    $ su - deployer
    $ mkdir ~/.ssh
    $ cd ~/.ssh
    $ ssh-keygen
    
Add authorized_keys
    $ nano authorized_keys # then add your key

Install Curl

    $ sudo apt-get update
    $ sudo apt-get install curl

Install RVM

    $ curl -L get.rvm.io | bash -s stable
    $ source /etc/profile.d/rvm.sh
    $ usermod -a -G rvm deployer
    $ rvm requirements
    $ rvm install 2.4.2
    $ rvm use 2.4.2 --default
    $ rvm rubygems current

Install PostgreSQL
	visit: https://www.postgresql.org/download/linux/ubuntu/
	or: https://askubuntu.com/questions/1052079/unable-to-install-postgresql-9-6-in-ubuntu-18-04
    $ sudo sh -c 'echo "deb http://apt.postgresql.org/pub/repos/apt/ `lsb_release -cs`-pgdg main" >> /etc/apt/sources.list.d/pgdg.list'
    $ wget -q https://www.postgresql.org/media/keys/ACCC4CF8.asc -O - | sudo apt-key add -
    
    $ sudo apt-get update  
    $ sudo apt-get upgrade
    $ sudo apt-get install postgresql-9.6 postgresql-server-dev-9.6
    $ gem install pg -- --with-pg-config=/usr/bin/pg_config

Create Postgres User

    $ sudo -u postgres psql
    create user deployer with password 'xxxxxxxx';
    alter role deployer superuser createrole createdb replication;
    create database MYAPP_DATABASE owner deployer;

Install GIT

    $ sudo apt-get install git-core

Install Bundler

    $ gem install bundler

Setup Nginx

    $ sudo apt-get install nginx
    $ nginx -h
    $ cat /etc/init.d/nginx
    $ /etc/init.d/nginx -h
    $ sudo service nginx start
    $ sudo vim /etc/nginx/sites-enabled/default

    upstream unicorn {
      server unix:/var/www/rails/MYAPP/current/tmp/sockets/unicorn.myapp.sock fail_timeout=0;
    }

    server {
      listen 80 default deferred;
      # server_name example.com;
      root /var/www/rails/MYAPP/current/public;

      location ^~ /assets/ {
		gzip_static on;
                expires max;
                add_header Cache-Control public;
      }

	location ~ ^/(robots.txt|sitemap.xml.gz)/ {
                root /var/www/rails/MYAPP/current/public;
        }

        try_files $uri/index.html $uri @unicorn;

        location @unicorn {
                proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
                proxy_set_header Host $http_host;
                proxy_redirect off;
                proxy_pass http://unicorn;
        }

        error_page 500 502 503 504 /500.html;
        client_max_body_size 4G;
        keepalive_timeout 10;
    }
    
Exit from ssh
	$ exit

Add Unicorn

	$ vim Gemfile
	
	gem "capistrano", "3.10"
	gem 'capistrano-rvm'
	gem 'capistrano-bundler'
	gem 'capistrano-rails'
	gem 'unicorn'
	gem 'capistrano3-unicorn'    

Update Unicorn Config

	$ vim config/unicorn/production.rb

    	root = "/var/www/rails/MY_APP/current"
	working_directory root

	pid "#{root}/tmp/pids/unicorn.pid"

	stderr_path "#{root}/log/unicorn_error.log"
	stdout_path "#{root}/log/unicorn_output.log"

	# worker_processes Integer(ENV['WEB_CONCURRENCY'])

	worker_processes 2
	timeout 10
	preload_app true

	listen "#{root}/tmp/sockets/unicorn.myapp.sock", backlog: 64

	before_fork do |server, worker|
	  Signal.trap 'TERM' do
	    puts 'Unicorn master intercepting TERM and sending myself QUIT instead'
	    Process.kill 'QUIT', Process.pid
	  end

	  defined?(ActiveRecord::Base) and
	    ActiveRecord::Base.connection.disconnect!
	end

	after_fork do |server, worker|
	  Signal.trap 'TERM' do
	    puts 'Unicorn worker intercepting TERM and doing nothing. Wait for master to send QUIT'
	  end

	  defined?(ActiveRecord::Base) and
	    ActiveRecord::Base.establish_connection
	end

	# Force the bundler gemfile environment variable to
	# reference the capistrano "current" symlink
	before_exec do |_|
	  ENV['BUNDLE_GEMFILE'] = File.join(root, 'Gemfile')
	end

Install Capistrano

    $ bundle exec cap install

Update Capistrano Capfile

	$ vim Capfile

    	# Load DSL and set up stages
	require "capistrano/setup"

	# Include default deployment tasks
	require "capistrano/deploy"

	# Load the SCM plugin appropriate to your project:
	#
	# require "capistrano/scm/hg"
	# install_plugin Capistrano::SCM::Hg
	# or
	# require "capistrano/scm/svn"
	# install_plugin Capistrano::SCM::Svn
	# or
	require "capistrano/scm/git"
	install_plugin Capistrano::SCM::Git

	# Include tasks from other gems included in your Gemfile
	#
	# For documentation on these, see for example:
	#
	#   https://github.com/capistrano/rvm
	#   https://github.com/capistrano/rbenv
	#   https://github.com/capistrano/chruby
	#   https://github.com/capistrano/bundler
	#   https://github.com/capistrano/rails
	#   https://github.com/capistrano/passenger
	#
	require "capistrano/rvm"
	# require "capistrano/rbenv"
	# require "capistrano/chruby"
	require "capistrano/bundler"
	# require "capistrano/rails/assets"
	require "capistrano/rails/migrations"
	# require "capistrano/passenger"
	require 'capistrano3/unicorn'

	# Load custom tasks from `lib/capistrano/tasks` if you have any defined
	Dir.glob("lib/capistrano/tasks/*.rake").each { |r| import r }

    
Update Capistrano Deploy Config

	$ vim config/deploy.rb

	# config valid for current version and patch releases of Capistrano
	# lock "~> 3.10.0"

	set :application, "MYAPP"
	set :repo_url, "[email protected]:dev-team-alpha/MYAPP.git"

	# Default branch is :master
	# ask :branch, `git rev-parse --abbrev-ref HEAD`.chomp

	# Default deploy_to directory is /var/www/my_app_name
	set :deploy_to, "/var/www/rails/MYAPP"

	# Default value for :format is :airbrussh.
	# set :format, :airbrussh

	# You can configure the Airbrussh format using :format_options.
	# These are the defaults.
	# set :format_options, command_output: true, log_file: "log/capistrano.log", color: :auto, truncate: :auto

	# Default value for :pty is false
	# set :pty, true

	# Default value for :linked_files is []
	append :linked_files, "config/database.yml", "config/application.yml"

	# Default value for linked_dirs is []
	append :linked_dirs, "log", "tmp/pids", "tmp/cache", "tmp/sockets", "public/system"

	# Default value for default_env is {}
	# set :default_env, { path: "/opt/ruby/bin:$PATH" }

	# Default value for local_user is ENV['USER']
	# set :local_user, -> { `git config user.name`.chomp }

	# Default value for keep_releases is 5
	set :keep_releases, 5

	# Uncomment the following to require manually verifying the host key before first deploy.
	# set :ssh_options, verify_host_key: :secure

	namespace :deploy do

	  desc 'Restart application'
	  task :restart do
	    on roles(:web), in: :sequence, wait: 5 do
	      execute :touch, release_path.join('tmp/restart.txt')
	    end
	  end

	end

	after 'deploy:restart', 'unicorn:duplicate'
    
Update Production Deploy Config

	$ vim config/deploy/production.rb

	set :port, 22
	set :user, 'ubuntu'
	set :deploy_via, :remote_cache
	set :use_sudo, false

	server '123.123.123.123', port: fetch(:port), user: fetch(:user), roles: %w{app db web}

	set :stage, :production
	set :rails_env, :production
	set :unicorn_env, :production
	set :unicorn_rack_env, 'production'
	set :branch, "master"
  

Add SSH Key to DigitalOcean

    $ cat ~/.ssh/id_rsa.pub | ssh -p 22 [email protected] 'cat >> ~/.ssh/authorized_keys'
    
Say Hi to Github

    # follow the steps in this guide if receive permission denied(public key)
    # https://help.github.com/articles/error-permission-denied-publickey
    $ ssh [email protected]    

Check Deployment (Commit and Push)

    $ cap production deploy:check
    
Deploy & restart unicorn

    $ cap production deploy
    $ bundle exec cap production unicorn:stop
    $ bundle exec cap production unicorn:start