planetstack/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 observer.error_mapper import error_mapper
   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):
  48         return []
  49         #return Sliver.objects.filter(ip=None)
  50
  51     def check_dependencies(self, obj, failed):
  52         for dep in self.dependencies:
  53             peer_name = dep[0].lower() + dep[1:]    # django names are camelCased with the first letter lower
  54             peer_object = getattr(obj, peer_name)
  55             if (peer_object.pk==failed.pk):
  56                 raise FailedDependency
  57
  58     def call(self, failed=[]):
  59         pending = self.fetch_pending()
  60         for o in pending:
  61             try:
  62                 for f in failed:
  63                     self.check_dependencies(o,f) # Raises exception if failed
  64                 self.sync_record(o)
  65                 o.enacted = datetime.now() # Is this the same timezone? XXX
  66                 o.save(update_fields=['enacted'])
  67             except Exception,e:
  68                 try:
  69                     o.backend_status = self.error_map.map(str(e))
  70                 except:
  71                     o.backend_status = str(e)
  72
  73                 o.save(update_fields=['backend_status'])
  74
  75                 logger.log_exc("sync step failed!")
  76                 failed.append(o)
  77
  78         return failed
  79
  80     def __call__(self, **args):
  81         return self.call(**args)