Unicorn Conf for Zero downtime Deploy !

gistfile1.txt

require "redis"
worker_processes 8
preload_app true
timeout 600
listen '/tmp/vodeclic.sock', :backlog => 1024
pid '/tmp/vodeclic.pid'


##
# REE

# http://www.rubyenterpriseedition.com/faq.html#adapt_apps_for_cow
if GC.respond_to?(:copy_on_write_friendly=)
  GC.copy_on_write_friendly = true
end

before_exec do |server|
  ENV["BUNDLE_GEMFILE"] = "/home/vodeclic/public_html/vodeclic/current/Gemfile"
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.
  
  # Disconnect since the database connection will not carry over
  if defined? ActiveRecord::Base
    ActiveRecord::Base.connection_handler.clear_all_connections!
  end

  old_pid = '/tmp/vodeclic.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


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
  
  # Start up the database connection again in the worker
  if defined?(ActiveRecord::Base)
    ActiveRecord::Base.establish_connection
  end

  #CHIMNEY.client.connect_to_server
  # Redis and Memcached would go here but their connections are established
  # on demand, so the master never opens a socket

  if Rails.cache.is_a?(ActiveSupport::Cache::MemCacheStore)
    Rails.cache.instance_variable_get(:@data).reset
  end

  Redis.current.quit

  ##
  # Unicorn master is started as root, which is fine, but let's
  # drop the workers to git:git

  begin
    uid, gid = Process.euid, Process.egid
    user, group = 'vodeclic', 'vodeclic'
    target_uid = Etc.getpwnam(user).uid
    target_gid = Etc.getgrnam(group).gid
    worker.tmp.chown(target_uid, target_gid)
    if uid != target_uid || gid != target_gid
      Process.initgroups(user, target_gid)
      Process::GID.change_privilege(target_gid)
      Process::UID.change_privilege(target_uid)
    end
  rescue => e
    if RAILS_ENV == 'development'
      STDERR.puts "couldn't change user, oh well"
    else
      raise e
    end
  end
end