AWS Certified Data Engineer – AssociateData Operations and MonitoringMedium
A global e-commerce company uses Amazon EventBridge to orchestrate various data pipelines that react to events from multiple AWS services and custom applications. They need to ensure that events are delivered reliably, even during temporary outages or processing delays in downstream targets. Specifically, they want to retain failed events for up to 24 hours to allow for manual inspection and reprocessing. Which EventBridge feature should they configure?
- ARetry policy for the EventBridge target.
- BDead-letter queue (DLQ) for the EventBridge rule.
- CInput Transformer for event modification.
- DArchive for event storage.
Show answer & explanationAnswer & explanation
Correct answer: B. Dead-letter queue (DLQ) for the EventBridge rule.
An EventBridge dead-letter queue (DLQ) is specifically designed to store events that fail to be delivered to a target after all retry attempts are exhausted. This allows for manual inspection and reprocessing of failed events, ensuring data durability and meeting the requirement to retain failed events for up to 24 hours.
Why the other options are wrong
- A. A retry policy allows EventBridge to re-attempt delivery to a target, which helps with transient issues, but if all retries fail, the event is lost unless a DLQ is configured.
- C. Input Transformer modifies the structure of an event before sending it to a target, but it doesn't handle delivery failures or retention of failed events.
- D. EventBridge Archives store *all* events (delivered or not) that match an event pattern for a longer period, primarily for auditing and replay, not specifically for retaining *failed* events for reprocessing.
EventBridge Dead-Letter Queues (DLQ)
A feature in Amazon EventBridge that allows undelivered events (after all retry attempts) to be sent to an SQS queue or SNS topic for later inspection, analysis, and reprocessing, ensuring no data loss.
- Configured at the target level for an EventBridge rule.
- Captures events that fail delivery after retries.
- Typically uses Amazon SQS as the underlying queue.
- Essential for building robust, fault-tolerant event-driven architectures.
Memory trick: EventBridge DLQ: Dead-Letter Queue keeps failed events, not lost due.