unicorn cap deploy

deploy.rb

#
# a simple cap recipe for deploying rack apps (such as sinatra or rails) using unicorn
# via scp using a dedicated deploy user with sudo access to run commands as the daemon user
#

# app options
set :application, 'app'
set :repository,  '.'     # deploy from the current working directory

# deploy options
set :scm,        :none    # use flat files, no git/svn/etc
set :deploy_via, :copy    # copy via scp to remote nodes
set :deploy_to,  '/var/www/app' # this directory will need to exist 
                                # or it's parent will need to be writeable by the deploy user

# user options
set :user,       'deploy' # ssh as the deploy user
set :use_sudo,   false    # do not use sudo unless specified

# ssh options
ssh_options[:keys] = ['~/.ssh/deploy.pem'] # use a dedicated private key for the deploy user
ssh_options[:forward_agent] = true

# misc options
default_run_options[:pty]   = true
set :normalize_asset_timestamps, false     # for apps without the following dirs: public/images, public/javascripts, public/stylesheets

# unicorn options
set :unicorn,      '/opt/ruby-1.9.2/bin/unicorn' # path to the unicorn binary if it's not in the deploy user's path 
set :unicorn_pid,  '/var/run/unicorn.pid'    # path to the configured location of unicorn's pid set in unicorn.rb
set :unicorn_conf, File.join(deploy_to, 'current', 'config', 'unicorn.rb') # path to unicorn.rb

# nodes
role :app, 'node.domain.tld'

# tasks
namespace :deploy do

  # reload by default instead of restart
  task :default do
    update
    reload
  end

  # start unicorn as the daemon user
  task :start do
    sudo "#{unicorn} -E production -c #{unicorn_conf} -D", :as => :daemon
  end

  # kill unicorn as the daemon user if pid exists
  task :stop do
    pid = capture "if [ -f #{unicorn_pid} ]; then cat #{unicorn_pid}; fi"

    if pid
      sudo "kill #{pid}", :as => :daemon
    end
  end

  # reload unicorn as the daemon user if pid exists
  task :reload do
    pid = capture "if [ -f #{unicorn_pid} ]; then cat #{unicorn_pid}; fi"

    if pid
      sudo "kill -USR2 #{pid}", :as => :daemon
    end
  end

  task :restart do
    stop
    start
  end
end

# clean up old deploys after a new deploy
after 'deploy:update',  'deploy:cleanup'

unicorn.rb

# unicorn settings
preload_app      true
timeout          60
worker_processes 10

# unicorn paths
pid    '/var/run/unicorn.pid'
listen '/var/run/unicorn.sock', :backlog => 2048

# app paths
working_directory '/var/www/app/current'
stderr_path       'log/unicorn.log'

# reload logic
before_fork do |server, worker|
  demoted_server_pid = "#{server.config[:pid]}.oldbin"

  unless demoted_server_pid == server.pid
    begin
      signal = case
      when (worker.nr + 1) >= server.worker_processes
        :QUIT
      else
        :TTOU
      end

      Process.kill signal, File.read(demoted_server_pid).to_i
    rescue Errno::ENOENT, Errno::ESRCH
    end
  end
end