adding epc-as-a-service, bring up entire custom service chain at once

Change-Id: I2e32e4e9f3479caf7648f8bde7629356691784d3
diff --git a/xos/tosca/resources/vepctenant.py b/xos/tosca/resources/vepctenant.py
new file mode 100644
index 0000000..e2089b2
--- /dev/null
+++ b/xos/tosca/resources/vepctenant.py
@@ -0,0 +1,31 @@
+from xosresource import XOSResource
+from core.models import Tenant, Service
+from services.vepc.models import VEPCTenant
+
+class XOSVEPCTenant(XOSResource):
+    provides = "tosca.nodes.VEPCTenant"
+    xos_model = VEPCTenant
+    name_field = None
+    copyin_props = ("description", "has_vhss", "has_vmme", "has_vmm", "has_vsm", "has_vsgwc", "has_vsgwu", "has_vpgwc", "has_vpgwu",)
+
+    def get_xos_args(self, throw_exception=True):
+        args = super(XOSVEPCTenant, self).get_xos_args()
+
+        provider_name = self.get_requirement("tosca.relationships.TenantOfService", throw_exception=throw_exception)
+        if provider_name:
+            args["provider_service"] = self.get_xos_object(Service, throw_exception=throw_exception, name=provider_name)
+
+        return args
+
+    def get_existing_objs(self):
+        args = self.get_xos_args(throw_exception=False)
+        provider_service = args.get("provider", None)
+        if provider_service:
+            return [ self.get_xos_object(provider_service=provider_service) ]
+        return []
+
+    def postprocess(self, obj):
+        pass
+
+    def can_delete(self, obj):
+        return super(XOSVEPCTenant, self).can_delete(obj)