unicorn.rb

unicorn.rb

# 2 workers and 1 master
worker_processes 2

# Load the app into the master before forking workers for fast worker spawn times
preload_app true

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

pid "/tmp/unicorn.my_site.pid"

# Listen on a Unix data socket
listen "/var/www/sample_rails_app/current/tmp/sockets/unicorn.sock", :backlog => 2048

stderr_path "/var/www/sample_rails_app/current/log/unicorn.stderr.log"
stdout_path "/var/www/sample_rails_app/current/log/unicorn.stdout.log"

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 = '/tmp/unicorn.my_site.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

before_exec do |server|
  # BUNDLE_GEMFILE is currently set to the explicit revision directory,
  # changing to the current directory so that we can do more deploys
  # after the original revision directory has been cycled out
  ENV['BUNDLE_GEMFILE'] = "/var/www/sample_rails_app/current/Gemfile"
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
  if defined?(ActiveRecord::Base)
    ActiveRecord::Base.establish_connection
  end
end