Unicorn config

unicorn.rb

rails_env = ENV['RAILS_ENV'] || 'production'
app = 'my_awesome_app'

# 4 workers and 1 master
worker_processes (rails_env == 'production' ? 4 : 1)

# Load rails+github.git into the master before forking workers
# for super-fast worker spawn times
preload_app true

# Restart any workers that haven't responded in 30 seconds
timeout 30

# Listen on a Unix data socket
case rails_env
when 'production' || 'staging'
  listen "/var/rails/#{app}/tmp/sockets/#{rails_env}.sock", :backlog => 2048
else
  listen "#{`pwd`.strip}/tmp/sockets/#{rails_env}.sock"
end

before_fork do |server, worker|
  # When sent a USR2, Unicorn will suffix its pidfile with .oldbin and
  # immediately start loading up a new version of itself (loaded with a new
  # version of our app). When this new Unicorn is completely loaded
  # it will begin spawning workers. The first worker spawned will check to
  # see if an .oldbin pidfile exists. If so, this means we've just booted up
  # a new Unicorn and need to tell the old one that it can now die. To do so
  # we send it a QUIT.
  #
  # Using this method we get 0 downtime deploys.
  old_pid = "#{Rails.root}/tmp/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

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

after_fork do |server, worker|
  # Unicorn master loads the app then forks off workers - because of the way
  # Unix forking works, we need to make sure we aren't using any of the parent's
  # sockets, e.g. db connection
  defined?(ActiveRecord::Base) and ActiveRecord::Base.establish_connection

  # Redis and Memcached would go here but their connections are established
  # on demand, so the master never opens a socket
  # $redis = Redis.connect
end