add vSGWU services

Change-Id: I8fb098b5cf81a6dc9061b6fd4187ce62164997c7
diff --git a/xos/models.py b/xos/models.py
new file mode 100644
index 0000000..3c8ef23
--- /dev/null
+++ b/xos/models.py
@@ -0,0 +1,57 @@
+from core.models.plcorebase import *
+from models_decl import VSGWUService_decl
+from models_decl import VSGWUTenant_decl
+
+from django.db import models
+from core.models import Service, PlCoreBase, Slice, Instance, Tenant, TenantWithContainer, Node, Image, User, Flavor, NetworkParameter, NetworkParameterType, Port, AddressPool
+from core.models.plcorebase import StrippedCharField
+import os
+from django.db import models, transaction
+from django.forms.models import model_to_dict
+from django.db.models import *
+from operator import itemgetter, attrgetter, methodcaller
+from core.models import Tag
+from core.models.service import LeastLoadedNodeScheduler
+import traceback
+from xos.exceptions import *
+from xos.config import Config
+from django.contrib.contenttypes.models import ContentType
+from django.contrib.contenttypes.fields import GenericForeignKey
+
+class VSGWUService(VSGWUService_decl):
+   class Meta:
+        proxy = True 
+
+class VSGWUTenant(VSGWUTenant_decl):
+   class Meta:
+        proxy = True 
+        
+   def __init__(self, *args, **kwargs):
+       vsgwuservice = VSGWUService.get_service_objects().all()
+       if vsgwuservice:
+           self._meta.get_field(
+                   "provider_service").default = vsgwuservice[0].id
+       super(VSGWUTenant, self).__init__(*args, **kwargs)
+
+   def save(self, *args, **kwargs):
+       super(VSGWUTenant, self).save(*args, **kwargs)
+       # This call needs to happen so that an instance is created for this
+       # tenant is created in the slice. One instance is created per tenant.
+       model_policy_vsgwutenant(self.pk)
+
+   def delete(self, *args, **kwargs):
+       # Delete the instance that was created for this tenant
+       self.cleanup_container()
+       super(VSGWUTenant, self).delete(*args, **kwargs)
+
+def model_policy_vsgwutenant(pk):
+    # This section of code is atomic to prevent race conditions
+    with transaction.atomic():
+        # We find all of the tenants that are waiting to update
+        tenant = VSGWUTenant.objects.select_for_update().filter(pk=pk)
+        if not tenant:
+            return
+        # Since this code is atomic it is safe to always use the first tenant
+        tenant = tenant[0]
+        tenant.manage_container()
+