lib/god/hub.rb

   1 module God
   2
   3   class Hub
   4     # directory to hold conditions and their corresponding metric
   5     #   key: condition
   6     #   val: metric
   7     @@directory = {}
   8
   9     def self.attach(condition, metric)
  10       # add the condition to the directory
  11       @@directory[condition] = metric
  12
  13       # schedule poll condition
  14       # register event condition
  15       if condition.kind_of?(PollCondition)
  16         Timer.get.schedule(condition, 0)
  17       else
  18         condition.register
  19       end
  20     end
  21
  22     def self.detach(condition)
  23       # remove the condition from the directory
  24       @@directory.delete(condition)
  25
  26       # unschedule any pending polls
  27       Timer.get.unschedule(condition)
  28
  29       # deregister event condition
  30       if condition.kind_of?(EventCondition)
  31         condition.deregister
  32       end
  33     end
  34
  35     def self.trigger(condition)
  36       if condition.kind_of?(PollCondition)
  37         self.handle_poll(condition)
  38       elsif condition.kind_of?(EventCondition)
  39         self.handle_event(condition)
  40       end
  41     end
  42
  43     def self.handle_poll(condition)
  44       Thread.new do
  45         begin
  46           metric = @@directory[condition]
  47           watch = metric.watch
  48
  49           watch.mutex.synchronize do
  50             result = condition.test
  51
  52             msg = watch.name + ' ' + condition.class.name + " [#{result}] " + metric.destination.inspect
  53             Syslog.debug(msg)
  54             puts msg
  55
  56             condition.after
  57
  58             if dest = metric.destination[result]
  59               watch.move(dest)
  60             else
  61               # reschedule
  62               Timer.get.schedule(condition)
  63             end
  64           end
  65         rescue => e
  66           message = format("Unhandled exception (%s): %s\n%s",
  67                            e.class, e.message, e.backtrace.join("\n"))
  68           Syslog.crit message
  69           abort message
  70         end
  71       end
  72     end
  73
  74     def self.handle_event(condition)
  75       Thread.new do
  76         metric = @@directory[condition]
  77         watch = metric.watch
  78
  79         watch.mutex.synchronize do
  80           msg = watch.name + ' ' + condition.class.name + " [true] " + metric.destination.inspect
  81           Syslog.debug(msg)
  82           puts msg
  83
  84           dest = metric.destination[true]
  85           watch.move(dest)
  86         end
  87       end
  88     end
  89   end
  90
  91 end