Question

A developer is building an e-commerce order service. When an order is placed, the system must simultaneously trigger an inventory update, send a confirmation email, and record analytics. Each of these three tasks is handled by a separate downstream component, and the components should not need to know about one another. The developer wants a loosely coupled, event-driven design where adding a fourth consumer later requires no changes to the order service. Which approach best meets these requirements?

Accepted Answer

Publish a single message to an Amazon SNS topic and subscribe the three downstream components so each receives its own copy of the event.

Answer

Have the order service invoke each downstream Lambda function directly and synchronously in sequence using the AWS SDK.

Answer

Write the order to a single Amazon SQS standard queue and have all three components poll the same queue for messages.

Answer

Store the order in DynamoDB and configure each downstream component to run a scheduled scan every minute to detect new orders.