Saga pattern for distributed transactions in RabbitMQ - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to send a message to start a saga transaction.

RabbitMQ

channel.basic_publish(exchange='saga_exchange', routing_key='start', body=[1])

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Astart_saga()

Border_id

C'{"order_id": 123}'

DNone

Attempts:

3 left

💡 Hint

Common Mistakes

Sending a variable name instead of a JSON string

Using None as message body

The message body must be a string or bytes representing the order details in JSON format.

2fill in blank

medium

Complete the code to acknowledge a message after processing in the saga.

RabbitMQ

channel.basic_ack(delivery_tag=[1])

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Amethod.delivery_tag

Bbody

Cchannel

Dmessage

Attempts:

3 left

💡 Hint

Common Mistakes

Using the message body instead of delivery tag

Using channel object as delivery tag

The delivery tag from the method frame is used to acknowledge the message.

3fill in blank

hard

Fix the error in the saga compensation step to publish a rollback message.

RabbitMQ

channel.basic_publish(exchange='saga_exchange', routing_key=[1], body=rollback_data)

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Arollback_data

Brollback

C'commit'

D'rollback'

Attempts:

3 left

💡 Hint

Common Mistakes

Using variable rollback_data as routing key

Omitting quotes around routing key

The routing key must be a string specifying the rollback action.

4fill in blank

hard

Fill both blanks to declare a durable queue and bind it to the saga exchange.

RabbitMQ

channel.queue_declare(queue=[1], durable=[2])
channel.queue_bind(queue='saga_queue', exchange='saga_exchange', routing_key='start')

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A'saga_queue'

BTrue

CFalse

D'start_queue'

Attempts:

3 left

💡 Hint

Common Mistakes

Using incorrect queue name

Setting durable to False causing message loss

The queue name must be a string and durability should be set to True for persistence.

5fill in blank

hard

Fill all three blanks to create a saga step that consumes messages, processes them, and sends a compensation if needed.

RabbitMQ

def on_message(channel, method, properties, body):
    data = json.loads(body)
    if data.get('status') == [1]:
        process(data)
    else:
        channel.basic_publish(exchange='saga_exchange', routing_key=[2], body=json.dumps(data))
    channel.basic_ack(delivery_tag=[3])

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

A'success'

B'rollback'

Cmethod.delivery_tag

D'fail'

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong status string

Not acknowledging messages properly

Using incorrect routing key for compensation

The saga step processes messages with status 'success', sends rollback messages on failure, and acknowledges using method.delivery_tag.