planetstack/model_policy.py

   1 from django.db.models.signals import post_save
   2 from django.dispatch import receiver
   3 import pdb
   4 from core.models import *
   5 from dependency_walker import *
   6 import model_policies
   7 from util.logger import logger
   8
   9 modelPolicyEnabled = True
  10
  11 def EnableModelPolicy(x):
  12     global modelPolicyEnabled
  13     modelPolicyEnabled = x
  14
  15 def update_dep(d, o):
  16         try:
  17                 if (d.updated < o.updated):
  18                         d.save(update_fields=['updated'])
  19         except AttributeError,e:
  20                 pdb.set_trace()
  21                 raise e
  22
  23 def delete_if_inactive(d, o):
  24         #print "Deleting %s (%s)"%(d,d.__class__.__name__)
  25         d.delete()
  26         return
  27
  28 @receiver(post_save)
  29 def post_save_handler(sender, instance, **kwargs):
  30         if not modelPolicyEnabled:
  31             return
  32
  33         sender_name = sender.__name__
  34         policy_name = 'model_policy_%s'%sender_name
  35
  36         if (not kwargs['update_fields']):
  37                 # Automatic dirtying
  38                 walk_inv_deps(update_dep, instance)
  39
  40                 try:
  41                         policy_handler = getattr(model_policies, policy_name, None)
  42                         if policy_handler is not None:
  43                                 policy_handler.handle(instance)
  44                 except:
  45                         logger.log_exc("Model Policy Error:")
  46         elif 'deleted' in kwargs['update_fields']:
  47                 walk_inv_deps(delete_if_inactive, instance)
  48