Handle null executor cancellations separately from other exceptions

util/asyncwrapper.py

@@ -54,10 +54,15 @@ class AsyncExecutorWrapper(object):
     return f
 
 
+class NullExecutorCancelled(CancelledError):
+  def __init__(self):
+    super(NullExecutorCancelled, self).__init__('Null executor always fails.')
+
+
 class NullExecutor(Executor):
   """ Executor instance which always returns a Future completed with a
       CancelledError exception. """
   def submit(self, _, *args, **kwargs):
     always_fail = Future()
-    always_fail.set_exception(CancelledError('Null executor always fails.'))
+    always_fail.set_exception(NullExecutorCancelled())
     return always_fail

util/saas/useranalytics.py

@@ -5,7 +5,7 @@ from hashlib import sha1
 from concurrent.futures import ThreadPoolExecutor
 from marketorestpython.client import MarketoClient
 
-from util.asyncwrapper import AsyncExecutorWrapper, NullExecutor
+from util.asyncwrapper import AsyncExecutorWrapper, NullExecutor, NullExecutorCancelled
 
 logger = logging.getLogger(__name__)
 
@@ -18,6 +18,8 @@ def build_error_callback(message_when_exception):
   def maybe_log_error(response_future):
     try:
       response_future.result()
+    except NullExecutorCancelled:
+      pass
     except Exception:
       logger.exception('User analytics: %s', message_when_exception)