unicorn code snippets

unicorn.rb

worker_processes 6

app_root = File.expand_path("../..", __FILE__)
working_directory app_root

# Listen on fs socket for better performance
listen "/tmp/unicorn.sock", :backlog => 64
listen 4096, :tcp_nopush => false

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

# App PID
pid "#{app_root}/tmp/pids/unicorn.pid"

# By default, the Unicorn logger will write to stderr.
# Additionally, some applications/frameworks log to stderr or stdout,
# so prevent them from going to /dev/null when daemenized here:
stderr_path "#{app_root}/log/unicorn.stderr.log"
stdout_path "#{app_root}/log/unicorn.stdout.log"

# To save some money and improve performance
preload_app true
GC.respond_to?(:copy_on_write_friendly=) and
  GC.copy_on_write_friendly = true

# Force the bundler gemfile environment variable to 
# reference the Capistrano "current" symlink
before_exec do |_|
  ENV["BUNDLE_GEMFILE"] = File.join(app_root, 'Gemfile')
end

before_fork do |server, worker|
  # 参考 http://unicorn.bogomips.org/SIGNALS.html
  # 使用USR2新号，以及在进程完成后用QUIT新号来实现无缝重启
  old_pid = app_root + '/tmp/pids/unicorn.pid.oldbin'
  if File.exist?(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

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