message: Don't cache if there's no cache key
diff: @@ -282,7 +282,11 @@ class BaseViz(object):
  data = None
  stacktrace = traceback.format_exc()
  - if data and cache and self.status != utils.QueryStatus.FAILED:
  + if (
  + data and
  + cache_key and
  + cache and
  + self.status != utils.QueryStatus.FAILED):
  cached_dttm = datetime.utcnow().isoformat().split('.')[0]
  try:
  cache_value = json.dumps({
  