vendor/rails/railties/lib/commands/ncgi/tracker

   1 #!/usr/bin/env ruby
   2
   3 require 'drb'
   4 require 'thread'
   5
   6 def message(s)
   7   $stderr.puts "tracker: #{s}" if ENV && ENV["DEBUG_GATEWAY"]
   8 end
   9
  10 class Tracker
  11   include DRbUndumped
  12
  13   def initialize(instances, socket_path)
  14     @instances = instances
  15     @socket = File.expand_path(socket_path)
  16     @active = false
  17
  18     @listeners = []
  19     @instances.times { @listeners << Mutex.new }
  20
  21     message "using #{@listeners.length} listeners"
  22     message "opening socket at #{@socket}"
  23
  24     @service = DRb.start_service("drbunix://#{@socket}", self)
  25   end
  26
  27   def with_listener
  28     message "listener requested"
  29
  30     mutex = has_lock = index = nil
  31     3.times do
  32       @listeners.each_with_index do |mutex, index|
  33         has_lock = mutex.try_lock
  34         break if has_lock
  35       end
  36       break if has_lock
  37       sleep 0.05
  38     end
  39
  40     if has_lock
  41       message "obtained listener #{index}"
  42       @active = true
  43       begin yield index
  44       ensure
  45         mutex.unlock
  46         message "released listener #{index}"
  47       end
  48     else
  49       message "dropping request because no listeners are available!"
  50     end
  51   end
  52
  53   def background(check_interval = nil)
  54     if check_interval
  55       loop do
  56         sleep check_interval
  57         message "Idle for #{check_interval}, shutting down" unless @active
  58         @active = false
  59         Kernel.exit 0
  60       end
  61     else DRb.thread.join
  62     end
  63   end
  64 end
  65
  66 socket_path = ARGV.shift
  67 instances = ARGV.shift.to_i
  68 t = Tracker.new(instances, socket_path)
  69 t.background(ARGV.first ? ARGV.shift.to_i : 90)