Message ordering in GCP - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to enable message ordering in a Pub/Sub topic.

GCP

topic = publisher.topic_path(project_id, [1])
publisher.create_topic(request={"name": topic, "message_ordering_enabled": true})

Drag options to blanks, or click blank then click option'

A"topic-name"

B"pubsub-topic"

C"my-topic"

D"ordered-topic"

Attempts:

3 left

💡 Hint

Common Mistakes

Using a generic topic name that doesn't indicate ordering

Not enabling message ordering in topic creation

Setting the topic name to 'ordered-topic' and enabling message_ordering_enabled ensures messages are published in order.

2fill in blank

medium

Complete the code to publish a message with ordering key.

GCP

future = publisher.publish(topic, data=b"Hello, world!", ordering_key=[1])

Drag options to blanks, or click blank then click option'

A"123"

B"key1"

C"order-1"

D"msg-key"

Attempts:

3 left

💡 Hint

Common Mistakes

Using non-string types for ordering key

Leaving ordering key empty

The ordering key must be a string. Here, 'key1' is used to group messages for ordering.

3fill in blank

hard

Fix the error in subscriber code to enable message ordering.

GCP

subscriber = pubsub_v1.SubscriberClient()
subscription_path = subscriber.subscription_path(project_id, subscription_name)
flow_control = pubsub_v1.types.FlowControl(max_messages=10)
streaming_pull_future = subscriber.subscribe(subscription_path, callback=callback, flow_control=[1], enable_message_ordering=True)

Drag options to blanks, or click blank then click option'

Amax_messages

BNone

Cflow_control

D10

Attempts:

3 left

💡 Hint

Common Mistakes

Passing an integer instead of flow control object

Passing None disables flow control and may break ordering

The flow_control parameter must be passed as an object to control message flow and preserve ordering.

4fill in blank

hard

Fill both blanks to configure the subscriber to acknowledge messages in order.

GCP

def callback(message):
    print(f"Received message: {message.data.decode('utf-8')}")
    message.[1]()

subscriber = pubsub_v1.SubscriberClient()
subscription_path = subscriber.subscription_path(project_id, subscription_name)
streaming_pull_future = subscriber.subscribe(subscription_path, callback=callback, enable_message_ordering=[2])

Drag options to blanks, or click blank then click option'

Aack

Bnack

CTrue

DFalse

Attempts:

3 left

💡 Hint

Common Mistakes

Using nack() instead of ack()

Not enabling message ordering in subscriber

Calling ack() acknowledges the message, and enabling enable_message_ordering=True ensures ordered delivery.

5fill in blank

hard

Fill all three blanks to create a topic, publish ordered messages, and enable ordering in subscriber.

GCP

topic = publisher.topic_path(project_id, [1])
publisher.create_topic(request={"name": topic, "message_ordering_enabled": [2])

future = publisher.publish(topic, data=b"Test", ordering_key=[3])

Drag options to blanks, or click blank then click option'

A"ordered-topic"

BTrue

C"key-123"

D"normal-topic"

Attempts:

3 left

💡 Hint

Common Mistakes

Not enabling message ordering in topic creation

Using a topic name that doesn't reflect ordering

Publishing without an ordering key

Use 'ordered-topic' as the topic name, enable message ordering with True, and publish with an ordering key 'key-123'.