Idempotent consumers in RabbitMQ - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to acknowledge a message after processing in RabbitMQ consumer.

RabbitMQ

channel.basic_ack(delivery_tag=[1])

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

Amethod.delivery_tag

Bchannel.delivery_tag

Cmessage.delivery_tag

Ddelivery_tag

Attempts:

3 left

💡 Hint

Common Mistakes

Using channel.delivery_tag which does not exist.

Using delivery_tag without context.

In RabbitMQ, the delivery tag is accessed via method.delivery_tag to acknowledge a message.

2fill in blank

medium

Complete the code to declare a durable queue in RabbitMQ.

RabbitMQ

channel.queue_declare(queue='task_queue', durable=[1])

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

AFalse

BTrue

CNone

D0

Attempts:

3 left

💡 Hint

Common Mistakes

Setting durable to False which makes the queue temporary.

Using None or 0 which are invalid for durable parameter.

Setting durable=True ensures the queue survives RabbitMQ restarts.

3fill in blank

hard

Fix the error in the consumer callback to ensure idempotent processing by checking message ID.

RabbitMQ

def callback(ch, method, properties, body):
    message_id = properties.[1]
    if message_id in processed_ids:
        ch.basic_ack(delivery_tag=method.delivery_tag)
        return
    # process message
    processed_ids.add(message_id)
    ch.basic_ack(delivery_tag=method.delivery_tag)

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

Amessage_id_property

Bmessage_id_header

Cmessage_id

Attempts:

3 left

💡 Hint

Common Mistakes

Using incorrect property names like message_id_header or message_id_property.

The message ID is accessed via properties.message_id to track processed messages for idempotency.

4fill in blank

hard

Fill both blanks to create a dictionary comprehension that stores message IDs and their bodies only if the ID is not already processed.

RabbitMQ

new_messages = {msg.[1]: msg.[2] for msg in messages if msg.[1] not in processed_ids}

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Amessage_id

Bbody

Ctimestamp

Ddelivery_tag

Attempts:

3 left

💡 Hint

Common Mistakes

Using timestamp or delivery_tag instead of message_id or body.

We use message_id as the key and body as the value to store unprocessed messages.

5fill in blank

hard

Fill all three blanks to complete the RabbitMQ consumer setup with manual acknowledgments and prefetch count for idempotent processing.

RabbitMQ

channel.basic_qos(prefetch_count=[1])
channel.basic_consume(queue='task_queue', on_message_callback=[2], auto_ack=[3])
channel.start_consuming()

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

A1

Bcallback

CFalse

DTrue

Attempts:

3 left

💡 Hint

Common Mistakes

Setting auto_ack=True which disables manual ack.

Using wrong callback function name.

Setting prefetch_count to 0 or more than 1.

Setting prefetch_count=1 limits unacknowledged messages to one. The callback function handles messages. auto_ack=False enables manual acknowledgments for idempotency.