Observed non-terminating stream error 503 DNS resolution failed for pubsub.googleapis.com:443: UNAVAILABLE: OS Error - google-cloud-pubsub

Question

I have Feed Completion listener program for GCS using a Pub/Sub subscription in tandem with a post-processing job.'''
subscriber = pubsub_v1.SubscriberClient(credentials=cred) subscription_path = subscriber.subscription_path(PROJECT, SUBSCRIPTION_NAME)
flow_control = pubsub_v1.types.FlowControl(max_messages=500)
streaming_pull_future = subscriber.subscribe(subscription_path, callback=callback, flow_control=flow_control)
with subscriber:
try:
streaming_pull_future.result(timeout=TIMEOUT)
except TimeoutError:
streaming_pull_future.cancel()
logging.info("The filewatcher process has completed.")
successes, failures = [], []
for feed in created_local_done_file:
if created_local_done_file[feed]:
successes.append(feed)
else:
failures.append(feed)
logging.info("These Juniper feeds completed and proceeded to the next step:")
counter = 1
for feed in successes:
logging.info("\t%s: %s", counter, feed)
counter += 1
logging.warning("These Juniper feeds did not publish a message to pub/sub (possibly due to failure):")
counter = 1
for feed in failures:
logging.warning("\t%s: %s", counter, feed)
counter += 1
if warn_of_dupes:
logging.warning("Reminder: There are overlapping feed names in the config files. This could cause errors/unexpected behaviour in the future!")
logging.info("Exiting...")
if len(failures) > 0:
sys.exit(1)
else:
sys.exit(0)
except Exception as error:
streaming_pull_future.cancel()
logging.critical("Listening for messages on %s threw an exception: %s.", SUBSCRIPTION_NAME, error)
sys.exit(1)
2022-06-17 09:12:25,932 PUB/SUB INFO -- List of feeds detected by the reader: {'XXX', 'YYY'}
2022-06-17 09:12:26,057 PUB/SUB INFO -- There are 2 feeds detected in total.
2022-06-17 09:12:26,057 PUB/SUB INFO -- Observed non-terminating stream error 503 DNS resolution failed for pubsub.googleapis.com:443: UNAVAILABLE: OS Error
2022-06-17 09:12:26,057 PUB/SUB INFO -- Listening for messages on projects/hsbc-11545401-datamesh-dev/subscriptions/datamesh-dev-control-api-service...
2022-06-17 09:12:26,057 PUB/SUB INFO -- Observed recoverable stream error 503 DNS resolution failed for pubsub.googleapis.com:443: UNAVAILABLE: OS Error