GCP Cloud Pub/Sub Message Ordering guide with Python Client Library
I'm trying to debug I'm currently working on a system that processes messages from a GCP Cloud Pub/Sub topic using the Python client library (`google-cloud-pubsub==2.12.0`)... I've configured my subscription to be ordered, but I'm working with an scenario where messages that should be processed in a specific sequence are not being received in that order. Here's the setup I'm using: ```python from google.cloud import pubsub_v1 project_id = 'my-project' topic_id = 'my-topic' subscription_id = 'my-subscription' publisher = pubsub_v1.PublisherClient() subscriber = pubsub_v1.SubscriberClient() topic_path = publisher.topic_path(project_id, topic_id) subscription_path = subscriber.subscription_path(project_id, subscription_id) # Publishing messages with an ordering key for i in range(5): data = f'Message {i}'.encode('utf-8') publisher.publish(topic_path, data, ordering_key='order-key') ``` And here's how I'm consuming these messages: ```python def callback(message): print(f'Received {message.data.decode()}') message.ack() streaming_pull_future = subscriber.subscribe(subscription_path, callback=callback) try: streaming_pull_future.result() except Exception as e: print(f'behavior occurred: {e}') ``` Despite specifying the same ordering key for all published messages, I see that they are being processed out of order. For example, I received `Message 2` before `Message 1`. I've also checked my subscription settings, and the ordering feature is indeed enabled. Additionally, the exact order is crucial for my application as it affects subsequent processing steps. Could there be something I'm missing in the setup that might lead to this behavior? Is there a known limitation in the GCP Pub/Sub ordering feature that might be causing these messages to arrive out of sequence? Any help would be greatly appreciated! Has anyone else encountered this? Has anyone else encountered this? I recently upgraded to Python LTS. I'm open to any suggestions.