26 May 2014

Ubuntu, Nginx, Unicorn, Rails, Capistrano, rbenv, Oh My!

require 'capistrano/setup'

require 'capistrano/deploy'

require 'capistrano/rbenv'

require 'capistrano/rails'

require 'capistrano3/unicorn'

Dir.glob('lib/capistrano/tasks/*.cap').each { |r| import r }

# config valid only for Capistrano 3.1
lock '3.2.1'

set :application, 'app-name'
set :repo_url, 'git@wherever.git'

set :linked_files, %w{config/database.yml .env}
set :linked_dirs, %w{tmp/pids}

set :unicorn_config_path, "config/unicorn.rb"

set :rbenv_type, :user # or :system, depends on your rbenv setup
set :rbenv_ruby, '2.1.1'
set :rbenv_prefix, "RBENV_ROOT=#{fetch(:rbenv_path)} RBENV_VERSION=#{fetch(:rbenv_ruby)} #{fetch(:rbenv_path)}/bin/rbenv exec"
set :rbenv_map_bins, %w{rake gem bundle ruby rails}
set :rbenv_roles, :all # default value

namespace :deploy do

  desc 'Restart application'
  task :restart do
    on roles(:app), in: :sequence, wait: 5 do
      invoke 'unicorn:restart'
    end
  end

  after :publishing, :restart

  after :restart, :clear_cache do
    on roles(:web), in: :groups, limit: 3, wait: 10 do
      # Here we can do anything such as:
      # within release_path do
      #   execute :rake, 'cache:clear'
      # end
    end
  end

end

set :stage, :production

set :deploy_to, '~/apps/app-name'

set :branch, 'master'

set :rails_env, 'production'

# Simple Role Syntax
# ==================
# Supports bulk-adding hosts to roles, the primary
# server in each group is considered to be the first
# unless any hosts have the primary property set.
role :app, %w{deploy@app-host}
role :web, %w{deploy@app-host}
role :db,  %w{deploy@app-host}

# Set environment to development unless something else is specified
env = ENV["RAILS_ENV"] || "development"


# Production specific settings
if env == "production"
  app_dir = "app-name"
  worker_processes 4
end

# listen on both a Unix domain socket and a TCP port,
# we use a shorter backlog for quicker failover when busy
listen "/tmp/unicorn.#{app_dir}.socket", :backlog => 64

# Preload our app for more speed
preload_app true

# nuke workers after 30 seconds instead of 60 seconds (the default)
timeout 30

# Help ensure your application will always spawn in the symlinked
# "current" directory that Capistrano sets up.
working_directory "/home/deploy/apps/#{app_dir}/current"

# feel free to point this anywhere accessible on the filesystem
user 'deploy', 'deploy'
shared_path = "/home/deploy/apps/#{app_dir}/shared"

stderr_path "#{shared_path}/log/unicorn.stderr.log"
stdout_path "#{shared_path}/log/unicorn.stdout.log"

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


before_fork do |server, worker|
  # the following is highly recomended for Rails + "preload_app true"
  # as there's no need for the master process to hold a connection
  if defined?(ActiveRecord::Base)
    ActiveRecord::Base.connection.disconnect!
  end

  # Before forking, kill the master process that belongs to the .oldbin PID.
  # This enables 0 downtime deploys.
  old_pid = "#{shared_path}/pids/unicorn.pid.oldbin"
  if File.exists?(old_pid) && server.pid != old_pid
    begin
      Process.kill("QUIT", File.read(old_pid).to_i)
    rescue Errno::ENOENT, Errno::ESRCH
      # someone else did our job for us
    end
  end
end

after_fork do |server, worker|
  # the following is *required* for Rails + "preload_app true",
  if defined?(ActiveRecord::Base)
    ActiveRecord::Base.establish_connection
  end
end