plugins/reservation.py

   1 # $Id$
   2 # $URL$
   3 #
   4 # NodeManager plugin - first step of handling reservable nodes
   5
   6 """
   7 Manages running slices when reservation_policy is 'lease_or_idle' or 'lease_or_shared'
   8 """
   9
  10 import time
  11 import threading
  12
  13 import logger
  14
  15 priority = 45
  16
  17 # this instructs nodemanager that we want to use the latest known data in case the plc link is down
  18 persistent_data = True
  19
  20 # of course things would be simpler if node manager was to create one instance of the plugins
  21 # instead of blindly caling functions in the module...
  22
  23 ##############################
  24 # rough implementation for a singleton class
  25 def Singleton (klass,*args,**kwds):
  26     if not hasattr(klass,'_instance'):
  27         klass._instance=klass(*args,**kwds)
  28     return klass._instance
  29
  30 def start(options, conf):
  31     return Singleton(reservation).start(options,conf)
  32
  33 def GetSlivers(data, conf = None, plc = None):
  34     return Singleton(reservation).GetSlivers(data, conf, plc)
  35
  36 ##############################
  37 class reservation:
  38
  39     def __init__ (self):
  40         # the last snapshot of data exposed by GetSlivers
  41         self.data = None
  42         # this is a dict mapping a raounded timestamp to the corr. Timer object
  43         self.timers = {}
  44
  45     # the granularity is set in the API (initial value is 15 minutes)
  46     # and it used to round all leases start/until times
  47     # changing this dynamically can have some weird effects of course..
  48     def granularity (self):
  49         try:
  50             return self.data['lease_granularity']
  51         # in case we'd try to access this before it's populated..
  52         except:
  53             return 60*60
  54
  55     # round to granularity
  56     def round_time (self, time):
  57         granularity=self.granularity()
  58         return ((int(time)+granularity/2)/granularity)*granularity
  59
  60     def clear_timers (self):
  61         for timer in self.timers.values():
  62             timer.cancel()
  63         self.timers={}
  64
  65     def clear_timer (self,timestamp):
  66         round=self.round_time(timestamp)
  67         if round in self.timers:
  68             timer=self.timers[round]
  69             timer.cancel()
  70             del self.timers[round]
  71
  72     def sync_timers_from_leases (self):
  73         self.clear_timers()
  74         for lease in self.data['leases']:
  75             self.ensure_timer(lease['t_from'])
  76             self.ensure_timer(lease['t_until'])
  77
  78     def ensure_timer(self, timestamp):
  79         now=time.time()
  80         # forget about past events
  81         if timestamp < now: return
  82         round=self.round_time(timestamp)
  83         if round in self.timers: return
  84         def this_closure ():
  85             self.round_time_callback (round)
  86         timer=threading.Timer(timestamp-now,this_closure)
  87         self.timers[round]=timer
  88         timer.start()
  89
  90     def round_time_callback (self, time_arg):
  91         now=time.time()
  92         round_now=self.round_time(now)
  93         logger.log('reservation.round_time_callback now=%f round_now=%d arg=%d...'%(now,round_now,time_arg))
  94         leases=self.data.leases
  95         if leases:
  96             logger.verbose('Listing leases beg')
  97             for lease in leases:
  98                 logger.verbose("lease=%r"%lease)
  99             logger.verbose('Listing leases end')
 100         for lease in leases:
 101             if lease['t_until']==round_now:
 102                 logger.log('Suspending slice %s - ending lease %d'%(lease['name'],lease['lease_id']))
 103                 self.suspend_slice (lease['name'])
 104         for lease in leases:
 105             if lease['t_from']==round_now:
 106                 logger.log('Starting slice %s - starting lease %d'%(lease['name'],lease['lease_id']))
 107                 self.restart_slice (lease['name'])
 108
 109
 110     def suspend_slice(self, slicename):
 111         logger.log('reservation.suspend_slice, slice %s, to be written'%slicename)
 112
 113     def restart_slice(self, slicename):
 114         logger.log('reservation.restart_slice, slice %s, to be written'%slicename)
 115
 116     def show_time (self, timestamp):
 117         return time.strftime ("%Y-%m-%d %H:%M %Z",time.gmtime(timestamp))
 118
 119     ####################
 120     def start(self,options,conf):
 121         logger.log("reservation: plugin performing dummy start...")
 122
 123     # this method is entirely about making sure that we have events scheduled
 124     # at the <granularity> intervals where there is a lease that starts or ends
 125     def GetSlivers (self, data, conf=None, plc=None):
 126
 127         # check we're using a compliant GetSlivers
 128         if 'reservation_policy' not in data:
 129             logger.log_missing_data("reservation.GetSlivers",'reservation_policy')
 130             return
 131         reservation_policy=data['reservation_policy']
 132         if 'leases' not in data:
 133             logger.log_missing_data("reservation.GetSlivers",'leases')
 134             return
 135
 136
 137         # store data locally
 138         # since we've asked for persistent_data, we should not get an empty data here
 139         if data: self.data = data
 140
 141         # regular nodes are not affected
 142         if reservation_policy == 'none':
 143             return
 144         elif reservation_policy not in ['lease_or_idle','lease_or_shared']:
 145             logger.log("reservation: ignoring -- unexpected value for reservation_policy %r"%reservation_policy)
 146             return
 147         # at this point we have reservation_policy in ['lease_or_idle','lease_or_shared']
 148         # we make no difference for now
 149         logger.verbose('reservation.GetSlivers : reservable node -- listing timers ')
 150
 151         self.sync_timers_from_leases()
 152         for timestamp in self.timers.keys():
 153             logger.verbose('TIMER armed for %s'%self.show_time(timestamp))
 154
 155         logger.verbose('reservation.GetSlivers : end listing timers')
 156