Mina deployment file to setup new host for Rails applications. Creates the folder structure, fill up the database.yml file, create the associated DB and user and set up new Apache virtual host file.

deploy.rb

require 'mina/bundler'
require 'mina/rails'
require 'mina/git'
require 'mina/rvm'

# Usually mina focuses on deploying to one host and the deploy options are therefore simple.
# In our case, there is a number of possible servers to deploy to, it is therefore necessary to
# specify the host that we are targeting.
server = ENV['server']
# Since the same host can have multiple applications running in parallel, it is necessary to
# specify further which application we want to deploy
version = ENV['version']

# Set the repository (here on BitBucket)
set :repository, '[email protected]:username/project.git'
# setting the term_mode to system disable the "pretty-print" but prevent some other issues
set :term_mode, :system

# Manually create these paths in shared/ (eg: shared/config/database.yml) in your server.
# They will be linked in the 'deploy:link_shared_paths' step.
set :shared_paths, ['config/database.yml', 'log']

# Optional SSH settings:
# SSH forward agent to ensure that credentials are passed through for git operations
set :forward_agent, true

##########################################################################
#
# Setup environment
#
##########################################################################

# This task is the environment that is loaded for most commands, such as
# `mina deploy` or `mina rake`.
task :environment do
  # Ensure that a server has been set
  unless server
    print_error "A server needs to be specified."
    exit
  end

  # Remote application folder
  set :deploy_to, "/home/username/project/#{version}"

  # Set the basic environment variables based on the server and version
  case server
  when 'qa'
    # The hostname to SSH to
    set :domain, 'qa-domain.com'
    # SSH Optional settings
    set :user, 'foobar'    # Username in the server to SSH to.
    # set :port, '30000'     # SSH port number.
    # Rails environment
    set :rails_env, 'qa'
  when 'prod'
    # The hostname to SSH to
    set :domain, 'prod-domain.com'
    # SSH Optional settings
    set :user, 'foobar'    # Username in the server to SSH to.
    # set :port, '30000'     # SSH port number.
    # Rails environment
    set :rails_env, 'production'
  end

  # For those using RVM, use this to load an RVM version@gemset.
  invoke :'rvm:use[ruby-1.9.3-p327@project]'
end

##########################################################################
#
# Create new host tasks
# Tasks below are related to deploying a new version of the application
#
##########################################################################

# Function extracted from http://blog.nicolai86.eu/posts/2013-05-06/syncing-database-content-down-with-mina
# allowing to read the content of the database.yml file
RYAML = <<-BASH
function ryaml {
  ruby -ryaml -e 'puts ARGV[1..-1].inject(YAML.load(File.read(ARGV[0]))) {|acc, key| acc[key] }' "$@"
};
BASH

# Execute all setup tasks defined below
desc "Create new folder structure + database.yml + DB + VirtualHost"
task :'setup:all' => :environment do
  queue! %[echo "-----> Setup folder structure on server"]
  invoke :setup
  queue! %[echo "-----> Setup the DB (create user / DB)"]
  invoke :'setup:db'
  queue! %[echo "-----> Setup Apache VirtualHost Configuration"]
  invoke :'setup:apache'
  queue! %[echo "-----> Deploy Master for this version"]
  invoke :deploy
  queue! %[echo "-----> Enable Apache host and restart Apache"]
  invoke :'apache:enable'
end

# Put any custom mkdir's in here for when `mina setup` is ran.
# For Rails apps, we'll make some of the shared paths that are shared between
# all releases.
task :setup => :environment do
  queue! %[mkdir -p "#{deploy_to}/shared/log"]
  queue! %[chmod g+rx,u+rwx "#{deploy_to}/shared/log"]

  queue! %[mkdir -p "#{deploy_to}/shared/config"]
  queue! %[chmod g+rx,u+rwx "#{deploy_to}/shared/config"]

  queue! %[touch "#{deploy_to}/shared/config/database.yml"]
  queue  %[echo "-----> Fill in information below to populate 'shared/config/database.yml'."]
  invoke :'setup:db:database_yml'
end

# Populate file database.yml with the appropriate rails_env
# Database name and user name are based on convention
# Password is defined by the user during setup
desc "Populate database.yml"
task :'setup:db:database_yml' => :environment do
  puts "Enter a name for the new database"
  db_name = STDIN.gets.chomp
  puts "Enter a user for the new database"
  db_username = STDIN.gets.chomp
  puts "Enter a password for the new database"
  db_pass = STDIN.gets.chomp
  # Virtual Host configuration file
  database_yml = <<-DATABASE.dedent
    #{rails_env}:
      adapter: mysql2
      encoding: utf8
      database: #{db_name}
      username: #{db_username}
      password: #{db_pass}
      host: localhost
      timeout: 5000
  DATABASE
  queue! %{
    echo "-----> Populating database.yml"
    echo "#{database_yml}" > #{deploy_to!}/shared/config/database.yml
    echo "-----> Done"
  }
end

# Create the new database based on information from database.yml
# In this application DB, user is given full access to the new DB
desc "Create new database"
task :'setup:db' => :environment do
  queue! %{
    echo "-----> Import RYAML function"
    #{RYAML}
    echo "-----> Read database.yml"
    USERNAME=$(ryaml #{deploy_to!}/#{shared_path!}/config/database.yml #{rails_env} username)
    PASSWORD=$(ryaml #{deploy_to!}/#{shared_path!}/config/database.yml #{rails_env} password)
    DATABASE=$(ryaml #{deploy_to!}/#{shared_path!}/config/database.yml #{rails_env} database)
    echo "-----> Create SQL query"
    Q1="CREATE DATABASE IF NOT EXISTS $DATABASE;"
    Q2="GRANT USAGE ON *.* TO $USERNAME@localhost IDENTIFIED BY '$PASSWORD';"
    Q3="GRANT ALL PRIVILEGES ON $DATABASE.* TO $USERNAME@localhost;"
    Q4="FLUSH PRIVILEGES;"
    SQL="${Q1}${Q2}${Q3}${Q4}"
    echo "-----> Execute SQL query to create DB and user"
    echo "-----> Enter MySQL root password on prompt below"
    #{echo_cmd %[mysql -uroot -p -e "$SQL"]}
    echo "-----> Done"
  }
end

# Create a new VirtualHost file
# Server name is defined by convention
# Script executes some sudo operations
desc "Create Apache site file"
task :'setup:apache' => :environment do
  # Get variable for virtual host configuration file
  fqdn = get_fqdn(server, version)
  fqdn_ext = external_fqdn(server, version)
  # Virtual Host configuration file
  vhost = <<-HOSTFILE.dedent
    <VirtualHost *:80>
      ServerAdmin [email protected]
      ServerName #{get_fqdn(server, version)}
      DocumentRoot #{deploy_to!}/#{current_path!}/public
      RailsEnv #{rails_env}
      <Directory #{deploy_to!}/#{current_path!}/public>
        Options -MultiViews
        AllowOverride all
      </Directory>
      PassengerMinInstances 5
      # Maintenance page
      ErrorDocument 503 /503.html
      RewriteEngine On
      RewriteCond %{REQUEST_URI} !.(css|gif|jpg|png)$
      RewriteCond %{DOCUMENT_ROOT}/503.html -f
      RewriteCond %{SCRIPT_FILENAME} !503.html
      RewriteRule ^.*$ - [redirect=503,last]
    </VirtualHost>
  HOSTFILE
  queue! %{
    echo "-----> Create Temporary Apache Virtual Host"
    echo "#{vhost}" > #{fqdn}.tmp
    echo "-----> Copy Virtual Host file to /etc/apache2/sites-available/ (requires sudo)"
    #{echo_cmd %[sudo cp #{fqdn}.tmp /etc/apache2/sites-available/#{fqdn}]}
    echo "-----> Remove Temporary Apache Virtual Host"
    rm #{fqdn}.tmp
    echo "-----> Done"
  }
end

# Enable the new Virtual Host and restart Apache
desc "Enable new Apache host file"
task :'apache:enable' => :environment do
  fqdn = get_fqdn(server, version)
  queue! %{
    echo "-----> Enable Apache Virtual Host"
    #{echo_cmd %[sudo a2ensite #{fqdn}]}
    echo "-----> Remove Temporary Apache Virtual Host"
    #{echo_cmd %[sudo service apache2 reload]}
  }
end

##########################################################################
#
# Deployment related task
#
##########################################################################

desc "Deploys the current version to the server."
task :deploy => :environment do
  deploy do
    # Put things that will set up an empty directory into a fully set-up
    # instance of your project.
    invoke :'git:clone'
    invoke :'deploy:link_shared_paths'
    invoke :'bundle:install'
    invoke :'rails:db_migrate'
    invoke :'rails:assets_precompile:force'

    to :launch do
      queue "touch #{deploy_to}/#{current_path}/tmp/restart.txt"
    end
  end
end

#########################################################################
#
# Helper functions
#
##########################################################################

#
# Get the main domain based on the server
#
# @return [String] the main domain
def main_domain(server)
  case server
  when 'qa'
    "qa-domain.com"
  when 'prod'
    "prod-domain.com"
  end
end

#
# Fully Qualified Domain Name of the host
# Concatenation of the version and the domain name
#
# @return [String] the FQDN
def get_fqdn(server, version)
  fqdn = "#{version}.#{main_domain(server)}"
  return fqdn
end

#########################################################################
#
# Libraries
#
##########################################################################

#
# See https://github.com/cespare/ruby-dedent/blob/master/lib/dedent.rb
#
class String
  def dedent
    lines = split "\n"
    return self if lines.empty?
    indents = lines.map do |line|
      line =~ /\S/ ? (line.start_with?(" ") ? line.match(/^ +/).offset(0)[1] : 0) : nil
    end
    min_indent = indents.compact.min
    return self if min_indent.zero?
    lines.map { |line| line =~ /\S/ ? line.gsub(/^ {#{min_indent}}/, "") : line }.join "\n"
  end
end