Pub/Sub: logs littered with "The bidirectional RPC exited". #8803

I am creating subscriptions to PubSub topics and reading messages from those subscriptions into queues. This is done interactively in a Jupyter notebook, so subscriptions can be created and destroyed repeatedly. In about ~20% of cases, I end up getting an error message logged to the console saying ERROR:google.api_core.bidi:The bidirectional RPC exited. However, I do not see that I am doing anything wrong?

Looking at the code where the error messages are emitted, it does not seem that anything pathological is going on. Maybe the severity of this error message should be reduced from _LOGGER.error("The bidirectional RPC exited.") to _LOGGER.info(...) or _LOGGER.debug(...)?

Environment details

Debian GNU/Linux rodete
Python 2.7.15
google-cloud-core=1.0.2
google-cloud-pubsub=0.41.1

Steps to reproduce

Run the following code snippet multiple times. Some of the times we get the error message ERROR:google.api_core.bidi:The bidirectional RPC exited.

Code example

import queue


def read_to_queue(subscription_path, topic_path):
    message_queue = queue.Queue()

    def callback(message):
        message.ack()
        message_queue.put(message.data)

    sub_client = pubsub_v1.SubscriberClient()
    _ = sub_client.create_subscription(subscription_path, topic_path)
    future = sub_client.subscribe(subscription_path, callback=callback)
    try:
        yield message_queue
    finally:
        future.cancel()
        sub_client.delete_subscription(subscription_path)

Stack trace

ERROR:google.api_core.bidi:The bidirectional RPC exited.
ERROR:google.api_core.bidi:The bidirectional RPC exited.
ERROR:google.api_core.bidi:The bidirectional RPC exited.
....
ERROR:google.api_core.bidi:The bidirectional RPC exited.