Merge pull request #8860 from CUB-OIT-PE/jinja-chain-undefined

Enabled jinja2.ChainableUndefined for custom webhook notifications

Reviewed-by: Ryan Petrello
             https://github.com/ryanpetrello

awx/main/models/notifications.py

@@ -12,7 +12,7 @@ from django.core.mail.message import EmailMessage
 from django.db import connection
 from django.utils.translation import ugettext_lazy as _
 from django.utils.encoding import smart_str, force_text
-from jinja2 import sandbox
+from jinja2 import sandbox, ChainableUndefined
 from jinja2.exceptions import TemplateSyntaxError, UndefinedError, SecurityError
 
 # AWX
@@ -429,7 +429,7 @@ class JobNotificationMixin(object):
         raise RuntimeError("Define me")
 
     def build_notification_message(self, nt, status):
-        env = sandbox.ImmutableSandboxedEnvironment()
+        env = sandbox.ImmutableSandboxedEnvironment(undefined=ChainableUndefined)
 
         from awx.api.serializers import UnifiedJobSerializer
         job_serialization = UnifiedJobSerializer(self).to_representation(self)