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(object):
  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             try:
  64                 peer_object = getattr(obj, peer_name)
  65             except:
  66                 peer_object = None
  67
  68             if (peer_object and peer_object.pk==failed.pk and type(peer_object)==type(failed)):
  69                 if (obj.backend_status!=peer_object.backend_status):
  70                     obj.backend_status = peer_object.backend_status
  71                     obj.save(update_fields=['backend_status'])
  72                 raise FailedDependency("Failed dependency for %s:%s peer %s:%s failed  %s:%s" % (obj.__class__.__name__, str(obj.pk), peer_object.__class__.__name__, str(peer_object.pk), failed.__class__.__name__, str(failed.pk)))
  73
  74     def call(self, failed=[], deletion=False):
  75         pending = self.fetch_pending(deletion)
  76         for o in pending:
  77             try:
  78                 for f in failed:
  79                     self.check_dependencies(o,f) # Raises exception if failed
  80                 if (deletion):
  81                     self.delete_record(o)
  82                     o.delete(purge=True)
  83                 else:
  84                     self.sync_record(o)
  85                     o.enacted = datetime.now() # Is this the same timezone? XXX
  86                     o.backend_status = "1 - OK"
  87                     o.save(update_fields=['enacted'])
  88             except Exception,e:
  89                 logger.log_exc("sync step failed!")
  90                 str_e = '%r'%e
  91                 try:
  92                     o.backend_status = '2 - %s'%self.error_map.map(str_e)
  93                 except:
  94                     o.backend_status = '2 - %s'%str_e
  95
  96                 # TOFIX:
  97                 # DatabaseError: value too long for type character varying(140)
  98                 if (o.pk):
  99                     try:
 100                         o.save(update_fields=['backend_status'])
 101                     except:
 102                         print "Could not update backend status field!"
 103                         pass
 104
 105                 failed.append(o)
 106
 107         return failed
 108
 109     def __call__(self, **args):
 110         return self.call(**args)