Fair dispatch with prefetch in RabbitMQ - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to set the prefetch count to 1 for fair dispatch.

RabbitMQ

channel.basic_qos(prefetch_count=[1])

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

A1

B0

C5

D10

Attempts:

3 left

💡 Hint

Common Mistakes

Setting prefetch_count to 0 disables prefetch and can cause unfair dispatch.

Using a high prefetch_count can overload a single worker.

Setting prefetch_count to 1 tells RabbitMQ to send only one message at a time to a worker, enabling fair dispatch.

2fill in blank

medium

Complete the code to acknowledge a message manually after processing.

RabbitMQ

channel.basic_ack(delivery_tag=[1])

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

Amethod.delivery_tag

Bmessage

Cchannel

Dprefetch_count

Attempts:

3 left

💡 Hint

Common Mistakes

Trying to acknowledge using the message body instead of delivery tag.

Using channel or prefetch_count as delivery tag.

The delivery_tag from the method frame is used to acknowledge the message manually.

3fill in blank

hard

Fix the error in the consumer callback to enable fair dispatch with manual acknowledgments.

RabbitMQ

def callback(ch, method, properties, body):
    print(f"Received {body}")
    # Process message
    ch.basic_ack(delivery_tag=[1])

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

Abody

Bproperties

Cmethod.delivery_tag

Dch

Attempts:

3 left

💡 Hint

Common Mistakes

Using the message body or channel object as delivery tag.

Not acknowledging messages causing them to be requeued.

Manual acknowledgment requires the delivery tag from the method parameter, which is method.delivery_tag.

4fill in blank

hard

Fill both blanks to set up a channel with fair dispatch and manual acknowledgments.

RabbitMQ

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

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

A1

BTrue

CFalse

D5

Attempts:

3 left

💡 Hint

Common Mistakes

Setting auto_ack to True disables manual acknowledgment.

Using a prefetch count higher than 1 reduces fairness.

Setting prefetch_count to 1 enables fair dispatch. Setting auto_ack to False requires manual acknowledgment.

5fill in blank

hard

Fill all three blanks to complete the consumer setup for fair dispatch with manual ack and a callback function.

RabbitMQ

def callback(ch, method, properties, body):
    print(f"Received {body}")
    # Process message
    ch.basic_ack(delivery_tag=[1])

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

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

Amethod.delivery_tag

B1

CFalse

DTrue

Attempts:

3 left

💡 Hint

Common Mistakes

Using auto_ack=True disables manual ack.

Not setting prefetch count to 1 reduces fairness.

The callback acknowledges messages using method.delivery_tag. Prefetch count is set to 1 for fair dispatch. auto_ack is False to require manual acknowledgment.