AI-200 practice: Queue and process back-end operations by using Azure Service Bus, including dead-letter queue handling, messages, topics, and subscriptions

Question 1

An order-processing system must guarantee that all messages for a single customer are processed strictly in the order they were sent, even though many customers' messages interleave on the same queue. Messages that fail processing after several attempts must be removed from the main queue automatically so they don't block that customer's remaining messages, while still being retained for manual review.

What should you configure?

Accepted Answer

A session-enabled Service Bus queue with session ID per customer, plus max delivery count so exhausted messages move to the dead-letter queue

Answer

A non-sessioned Service Bus queue with a single consumer thread, relying only on FIFO delivery order across all customers on that shared queue endpoint

Answer

A Service Bus topic with one subscription per customer and no dead-letter configuration, expecting failed messages to stay invisible after retries

Answer

An Azure Storage queue with visibility timeout set to zero so failed messages become immediately available to any other competing consumer

Question 2

A Service Bus topic publishes events for all order-state changes. One subscriber needs only events where a custom property priority equals "high" AND region equals "EU"; a second subscriber needs only events matching a specific correlationId tied to one workflow instance.

Which filter types should you configure, respectively?

Accepted Answer

A SQL filter on the first subscription for the priority and region expression, and a correlation filter on the second matching CorrelationId exactly

Answer

Correlation filters on both subscriptions, because correlation filters can evaluate arbitrary boolean expressions on custom properties

Answer

SQL filters on both subscriptions, because correlation filters are deprecated in Service Bus and can no longer match CorrelationId values

Answer

No subscription filters; publish high-priority EU events and correlation-scoped events to two separate topics that each subscriber reads

Question 3

You configure a Service Bus-triggered function that must process messages with limited concurrency to avoid overwhelming a downstream API, and dead-letter messages that fail repeatedly:
```json
// host.json
{
  "version": "2.0",
  "extensions": {
    "serviceBus": {
      "maxConcurrentCalls": 1,
      "maxAutoLockRenewalDuration": "00:05:00"
    }
  }
}
```
```python
@app.function_name(name="ProcessOrder")
@app.service_bus_queue_trigger(
    arg_name="msg",
    queue_name="orders",
    connection="ServiceBusConnection"
)
def process_order(msg: func.ServiceBusMessage):
    body = msg.get_body().decode("utf-8")
    call_downstream_api(body)
```
Messages that repeatedly fail are being reprocessed indefinitely rather than being dead-lettered after a reasonable number of attempts. What must be configured to achieve automatic dead-lettering after repeated failures?

Accepted Answer

Dead-lettering after repeated delivery failures is governed by the Service Bus queue's own MaxDeliveryCount setting (configured on the Service Bus namespace/queue itself, e.g., via Azure CLI az servicebus queue update --max-delivery-count 5), not by host.json.

Answer

maxConcurrentCalls must be increased, since a value of 1 disables dead-lettering entirely.

Answer

Add "deadLetteringOnMessageExpiration": true to host.json's serviceBus extension section.

Answer

The function code must explicitly catch exceptions and call msg.dead_letter() for every failure.

Question 4

Which Azure service should you use to reliably queue back-end processing tasks (such as document embedding jobs) with guaranteed delivery and support for dead-letter handling?

Accepted Answer

Azure Service Bus

Answer

Azure Event Grid

Answer

Azure Blob Storage

Answer

Azure CDN delivery

Question 5

Messages in an Azure Service Bus queue that repeatedly fail processing (e.g., due to malformed embedding requests) should be automatically moved aside after a maximum delivery count is reached. What handles this?

Accepted Answer

Dead-letter queue after MaxDeliveryCount

Answer

Hourly script that deletes failed messages

Answer

Event Grid retry policy on the publisher

Answer

Indefinitely raised message TTL on the queue

Question 6

You need multiple independent downstream systems (an indexing service, an audit service, and a notification service) to each receive a copy of every 'document uploaded' message. Which Service Bus entity type should you use?

Accepted Answer

Topic with multiple subscriptions

Answer

Single queue shared by all consumers

Answer

One queue per message with round-robin

Answer

Session-enabled queue without any topic

Question 7

An AI pipeline uses Service Bus topics with subscriptions filtered by message properties (e.g., only 'priority=high' messages go to an urgent-processing subscription). Which subscription feature enables this?

Accepted Answer

SQL or correlation filter on the subscription

Answer

Dead-letter queue attached to the topic root

Answer

Partitioning enabled on the Service Bus namespace

Answer

Longer lock duration on the subscription entity

Question 8

A Service Bus-triggered Azure Function processing embedding jobs must guarantee that messages are only removed from the queue after processing succeeds, so a function crash mid-processing causes automatic redelivery. What behavior achieves this?

Accepted Answer

PeekLock complete-after-success (Functions default)

Answer

ReceiveAndDelete removing messages on first receive

Answer

Retries disabled at the Service Bus namespace level

Answer

Message TTL set to zero so items expire instantly

Question 9

A high-throughput AI ingestion pipeline needs ordered processing of events per customer, guaranteeing that events for the same customer are always processed in the order they were sent, while different customers can be processed in parallel. Which Service Bus feature should you use?

Accepted Answer

Sessions using customer ID as the SessionId

Answer

Single unsharded queue with default global FIFO

Answer

Topics with no subscription filters configured

Answer

Shared partition key without enabling sessions

Question 10

Which of the following is the correct Azure CLI command to create a new Service Bus namespace in the 'Standard' pricing tier?

Accepted Answer

az servicebus namespace create --name myNamespace --resource-group myRG --sku Standard

Answer

az servicebus create --name myNamespace --resource-group myRG --tier Standard

Answer

az servicebus queue create --namespace myNamespace --name q1 --sku Standard

Answer

az sb namespace new --name myNamespace --resource-group myRG --sku Standard

19 questions