Dead letter queue pattern in Kafka - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to send a message to the dead letter queue topic.

Kafka

producer.send("[1]", record);

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

Amain-topic

Bdead-letter-queue

Cretry-topic

Derror-topic

Attempts:

3 left

💡 Hint

Common Mistakes

Sending the message to the main topic instead of the dead letter queue.

Using a retry topic instead of the dead letter queue.

The dead letter queue topic is where failed messages are sent, so the producer must send to 'dead-letter-queue'.

2fill in blank

medium

Complete the code to check if the message processing failed and send it to the dead letter queue.

Kafka

if (processingFailed) {
    producer.send("[1]", message);
}

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

Adead-letter-queue

Bretry-topic

Cmain-topic

Dsuccess-topic

Attempts:

3 left

💡 Hint

Common Mistakes

Sending failed messages back to the main topic.

Sending failed messages to a retry topic instead of dead letter queue.

When processing fails, the message should be sent to the dead letter queue topic.

3fill in blank

hard

Fix the error in the consumer code to consume messages from the dead letter queue topic.

Kafka

consumer.subscribe(Collections.singletonList("[1]"));

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

Adead-letter-queue

Bmain-topic

Cretry-topic

Derror-topic

Attempts:

3 left

💡 Hint

Common Mistakes

Subscribing to the main topic instead of the dead letter queue.

Using a retry topic for dead letter messages.

To consume dead letter messages, the consumer must subscribe to the 'dead-letter-queue' topic.

4fill in blank

hard

Fill both blanks to create a dead letter queue producer and send a failed message.

Kafka

KafkaProducer<String, String> producer = new KafkaProducer<>(props);
producer.send(new ProducerRecord<String, String>("[1]", "[2]"));

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

Adead-letter-queue

BfailedMessage

Cmain-topic

DsuccessMessage

Attempts:

3 left

💡 Hint

Common Mistakes

Sending success messages to the dead letter queue.

Using the main topic for failed messages.

The producer sends the failed message to the 'dead-letter-queue' topic.

5fill in blank

hard

Fill all three blanks to filter messages and send only failed ones to the dead letter queue.

Kafka

for (var record : consumer.poll(Duration.ofMillis(100))) {
    if (record.value().[1]("error")) {
        producer.send(new ProducerRecord<>("[2]", record.value()));
    } else {
        producer.send(new ProducerRecord<>("[3]", record.value()));
    }
}

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

Acontains

Bdead-letter-queue

Cmain-topic

DstartsWith

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'startsWith' instead of 'contains' to check for errors.

Sending all messages to the dead letter queue.

We check if the message contains 'error' to send it to the dead letter queue; otherwise, it goes to the main topic.