When a snow-emergency flag flips, the same alert must reach SMS subscribers, a dashboard queue, and a logging archive without the weather service calling each consumer itself. Which pattern should developers use?
Select an answer to reveal the explanation.
Short Explanation
One megaphone, many listeners — that is fanout. Publish the snow alert once and let SMS, the dashboard queue, and the archive each subscribe. The weather service should not dial every consumer itself.
Full Explanation
Fanout publishes a single event to many subscribers so producers stay decoupled from consumer lists. Amazon SNS is the classic AWS pub/sub fanout target; SQS queues and other endpoints can subscribe independently. Direct HTTPS fan-in at the producer, local-disk handoffs, and a single blocking Lambda that owns every side effect reintroduce coupling and failure blast radius.