lib/god/hub.rb

   1 module God
   2
   3   class Hub
   4     class << self
   5       # directory to hold conditions and their corresponding metric
   6       # {condition => metric}
   7       attr_accessor :directory
   8     end
   9
  10     self.directory = {}
  11
  12     def self.attach(condition, metric)
  13       self.directory[condition] = metric
  14
  15       case condition
  16         when PollCondition
  17           Timer.get.schedule(condition, 0)
  18         when EventCondition, TriggerCondition
  19           condition.register
  20       end
  21     end
  22
  23     def self.detach(condition)
  24       self.directory.delete(condition)
  25
  26       case condition
  27         when PollCondition
  28           Timer.get.unschedule(condition)
  29         when EventCondition, TriggerCondition
  30           condition.deregister
  31       end
  32     end
  33
  34     def self.trigger(condition)
  35       case condition
  36         when PollCondition
  37           self.handle_poll(condition)
  38         when EventCondition, TriggerCondition
  39           self.handle_event(condition)
  40       end
  41     end
  42
  43     def self.handle_poll(condition)
  44       Thread.new do
  45         begin
  46           metric = self.directory[condition]
  47
  48           # it's possible that the timer will trigger an event before it can be cleared
  49           # by an exiting metric, in which case it should be ignored
  50           unless metric.nil?
  51             watch = metric.watch
  52
  53             watch.mutex.synchronize do
  54               # run the test
  55               result = condition.test
  56
  57               # log
  58               self.log(watch, metric, condition, result)
  59
  60               # notify
  61               if condition.notify
  62                 self.notify(condition, msg)
  63               end
  64
  65               # after-condition
  66               condition.after
  67
  68               # get the destination
  69               dest =
  70               if result && condition.transition
  71                 # condition override
  72                 condition.transition
  73               else
  74                 # regular
  75                 metric.destination && metric.destination[result]
  76               end
  77
  78               # transition or reschedule
  79               if dest
  80                 # transition
  81                 begin
  82                   watch.move(dest)
  83                 rescue EventRegistrationFailedError
  84                   msg = watch.name + ' Event registration failed, moving back to previous state'
  85                   Syslog.debug(msg)
  86                   LOG.log(watch, :info, msg)
  87
  88                   dest = watch.state
  89                   retry
  90                 end
  91               else
  92                 # reschedule
  93                 Timer.get.schedule(condition)
  94               end
  95             end
  96           end
  97         rescue => e
  98           message = format("Unhandled exception (%s): %s\n%s",
  99                            e.class, e.message, e.backtrace.join("\n"))
 100           Syslog.crit message
 101           abort message
 102         end
 103       end
 104     end
 105
 106     def self.handle_event(condition)
 107       Thread.new do
 108         metric = self.directory[condition]
 109
 110         unless metric.nil?
 111           watch = metric.watch
 112
 113           watch.mutex.synchronize do
 114             # log
 115             self.log(watch, metric, condition, true)
 116
 117             # notify
 118             if condition.notify
 119               self.notify(condition, msg)
 120             end
 121
 122             # get the destination
 123             dest =
 124             if condition.transition
 125               # condition override
 126               condition.transition
 127             else
 128               # regular
 129               metric.destination && metric.destination[true]
 130             end
 131
 132             if dest
 133               watch.move(dest)
 134             end
 135           end
 136         end
 137       end
 138     end
 139
 140     # helpers
 141
 142     def self.log(watch, metric, condition, result)
 143       # log info if available
 144       if condition.info
 145         begin
 146           status =
 147           if (metric.destination && metric.destination.keys.size == 2) || result == true
 148             "[trigger]"
 149           else
 150             "[ok]"
 151           end
 152
 153           Array(condition.info).each do |condition_info|
 154             msg = "#{watch.name} #{status} #{condition_info} (#{condition.base_name})"
 155             Syslog.debug(msg)
 156             LOG.log(watch, :info, msg % [])
 157           end
 158         rescue Exception => e
 159           puts e.message
 160           puts e.backtrace.join("\n")
 161         end
 162       else
 163         msg = "#{watch.name} [unknown] (#{condition.base_name})"
 164         Syslog.debug(msg)
 165         LOG.log(watch, :info, msg % [])
 166       end
 167
 168       # log
 169       msg = watch.name + ' ' + condition.base_name + " [#{result}] " + self.dest_desc(metric, condition)
 170       Syslog.debug(msg)
 171       LOG.log(watch, :debug, msg)
 172     end
 173
 174     def self.dest_desc(metric, condition)
 175       if condition.transition
 176         {true => condition.transition}.inspect
 177       else
 178         if metric.destination
 179           metric.destination.inspect
 180         else
 181           'none'
 182         end
 183       end
 184     end
 185
 186     def self.notify(condition, message)
 187       begin
 188         spec = Contact.normalize(condition.notify)
 189
 190         # resolve contacts
 191         resolved_contacts =
 192         spec[:contacts].inject([]) do |acc, contact_name_or_group|
 193           acc += Array(God.contacts[contact_name_or_group] || God.contact_groups[contact_name_or_group])
 194           acc
 195         end
 196
 197         p resolved_contacts
 198
 199         resolved_contacts.each do |c|
 200           c.notify(message, Time.now, spec[:priority], spec[:category])
 201         end
 202       rescue => e
 203         puts e.message
 204         puts e.backtrace.join("\n")
 205       end
 206     end
 207   end
 208
 209 end