planetstack/openstack_observer/syncstep.py

   1 import os
   2 import base64
   3 from datetime import datetime
   4 from planetstack.config import Config
   5 from util.logger import Logger, logging
   6 from observer.steps import *
   7 from django.db.models import F, Q
   8
   9 logger = Logger(level=logging.INFO)
  10
  11 class FailedDependency(Exception):
  12     pass
  13
  14 class SyncStep:
  15     """ A PlanetStack Sync step.
  16
  17     Attributes:
  18         psmodel        Model name the step synchronizes
  19         dependencies    list of names of models that must be synchronized first if the current model depends on them
  20     """
  21     slow=False
  22     def get_prop(prop):
  23         try:
  24             sync_config_dir = Config().sync_config_dir
  25         except:
  26             sync_config_dir = '/etc/planetstack/sync'
  27         prop_config_path = '/'.join(sync_config_dir,self.name,prop)
  28         return open(prop_config_path).read().rstrip()
  29
  30     def __init__(self, **args):
  31         """Initialize a sync step
  32            Keyword arguments:
  33                    name -- Name of the step
  34                 provides -- PlanetStack models sync'd by this step
  35         """
  36         dependencies = []
  37         self.driver = args.get('driver')
  38         self.error_map = args.get('error_map')
  39
  40         try:
  41             self.soft_deadline = int(self.get_prop('soft_deadline_seconds'))
  42         except:
  43             self.soft_deadline = 5 # 5 seconds
  44
  45         return
  46
  47     def fetch_pending(self, deletion=False):
  48         # This is the most common implementation of fetch_pending
  49         # Steps should override it if they have their own logic
  50         # for figuring out what objects are outstanding.
  51         main_obj = self.provides[0]
  52         if (not deletion):
  53             objs = main_obj.objects.filter(Q(enacted__lt=F('updated')) | Q(enacted=None))
  54         else:
  55             objs = main_obj.deleted_objects.all()
  56
  57         return objs
  58         #return Sliver.objects.filter(ip=None)
  59
  60     def check_dependencies(self, obj, failed):
  61         for dep in self.dependencies:
  62             peer_name = dep[0].lower() + dep[1:]    # django names are camelCased with the first letter lower
  63             peer_object = getattr(obj, peer_name)
  64             if (peer_object and peer_object.pk==failed.pk and type(peer_object)==type(failed)):
  65                 raise FailedDependency("Failed dependency for %s:%s peer %s:%s failed  %s:%s" % (obj.__class__.__name__, str(obj.pk\\r
  66 ), peer_object.__class__.__name__, str(peer_object.pk), failed.__class__.__name__, str(failed.pk)))
  67
  68     def call(self, failed=[], deletion=False):
  69         pending = self.fetch_pending(deletion)
  70         for o in pending:
  71             try:
  72                 for f in failed:
  73                     self.check_dependencies(o,f) # Raises exception if failed
  74                 if (deletion):
  75                     self.delete_record(o)
  76                     o.delete(purge=True)
  77                 else:
  78                     self.sync_record(o)
  79                     o.enacted = datetime.now() # Is this the same timezone? XXX
  80                     o.backend_status = "OK"
  81                     o.save(update_fields=['enacted'])
  82             except Exception,e:
  83                 try:
  84                     o.backend_status = self.error_map.map(str(e))
  85                 except:
  86                     o.backend_status = str(e)
  87
  88                 if (o.pk):
  89                     o.save(update_fields=['backend_status'])
  90
  91                 logger.log_exc("sync step failed!")
  92                 failed.append(o)
  93
  94         return failed
  95
  96     def __call__(self, **args):
  97         return self.call(**args)