message: Disable discovery cache for TPUClusterResolver.
diff: @@ -108,13 +108,11 @@ class TPUClusterResolver(ClusterResolver):
  if self._discovery_url:
  return discovery.build(
  - 'tpu', 'v1alpha1',
  - credentials=credentials,
  - discoveryServiceUrl=self._discovery_url)
  + 'tpu', 'v1alpha1', credentials=credentials,
  + discoveryServiceUrl=self._discovery_url, cache_discovery=False)
  else:
  return discovery.build(
  - 'tpu', 'v1alpha1',
  - credentials=credentials)
  + 'tpu', 'v1alpha1', credentials=credentials, cache_discovery=False)
  def _request_compute_metadata(self, path):
  req = Request('%s/computeMetadata/v1/%s' % (_GCE_METADATA_ENDPOINT, path),
  