unicorn startup/management script (to work from capistrano)

unicorn.rb

# ------------------------------------------------------------------------------
# Sample rails 3 config
# ------------------------------------------------------------------------------

# Set your full path to application.
app_path = "/srv/www/xxx/current"

# Set unicorn options
worker_processes 2
preload_app true
#timeout 30
listen 3000 #listen to port 3000 for all interfaces (iptables will forward from port 80)

# Spawn unicorn master worker for user apps (group: apps)
user 'xxx', 'users'

# Fill path to your app
working_directory app_path

# Should be 'production' by default, otherwise use other env
rails_env = ENV['RAILS_ENV'] || 'production'

# Log everything to one file
stderr_path "log/unicorn.log"
stdout_path "log/unicorn.log"

# Set master PID location
pid_path = "#{app_path}/tmp/pids/unicorn.pid"
pid pid_path

before_fork do |server, worker|
  ActiveRecord::Base.connection.disconnect! if defined?(ActiveRecord::Base)

  ##ENsure you do not point to an old capistrano release
  ENV['BUNDLE_GEMFILE'] = File.join(app_path, "Gemfile")

  old_pid_file = "#{pid_path}.oldbin"
  old_pid = File.exists?(old_pid_file) && File.read(old_pid_file).to_i
  if old_pid && server.pid != old_pid
    puts "Killing old unicorn with PID #{old_pid}..."
    begin
      Process.kill("QUIT", old_pid)
    rescue Errno::ENOENT, Errno::ESRCH
      # someone else did our job for us
    end
  end
end

after_fork do |server, worker|
  ActiveRecord::Base.establish_connection if defined?(ActiveRecord::Base)
end