A developer is creating a service that uses an Amazon S3 bucket for image uploads. The service will use an AWS Lambda function to create a thumbnail…

This scenario requires a "fan-out" pattern, where a single event (an S3 object creation) triggers multiple, independent actions (Lambda invocation and email notification). Amazon Simple Notification Service (SNS) is designed specifically for this pub/sub, fan-out messaging model.

By configuring S3 event notifications to publish to an SNS topic, the event is sent to a central point. The Lambda function can subscribe to this topic to process the image, and an email endpoint can also be subscribed to the same topic to send the notification. This architecture is efficient, decoupled, and directly addresses both requirements using the most appropriate services.

B: This option is overly complex. There is no native capability to create an email subscription directly to an SQS queue. The SQS queue adds an unnecessary and non-functional step for the email notification.

C: Amazon SQS is a queueing service, not a fan-out service. A message sent to an SQS queue is typically processed by only one consumer. Also, SQS does not support direct email subscriptions.

D: While EventBridge can handle fan-out, this solution incorrectly routes the notification to an SQS queue. SQS does not support direct email subscriptions, making the final step of the notification workflow invalid.

1. AWS S3 Developer Guide: "Configuring Amazon S3 event notifications" - This document lists Amazon SNS topics

Amazon SQS queues

and AWS Lambda functions as supported destinations for S3 event notifications. This validates the initial step of the correct architecture. (See section: "Event notification destinations").

2. AWS SNS Developer Guide: "Common Amazon SNS scenarios" - The "Fanout" scenario is explicitly described: "a message published to an SNS topic can be replicated and pushed to multiple endpoints... For example

you can... send a message to an Amazon SQS queue

which then sends the message to a Lambda function." This confirms SNS is the correct service for fan-out to multiple subscriber types. (See section: "Fanout").

3. AWS SNS Developer Guide: "Subscribing to an Amazon SNS topic" - This page lists the available protocols for subscriptions

which include AWS Lambda and Email/Email-JSON. This confirms that both required actions can be subscribed to a single SNS topic. (See table: "Subscription and delivery protocols").

4. AWS Lambda Developer Guide: "Using AWS Lambda with Amazon SNS" - This guide details how to use an SNS topic to trigger a Lambda function

which is a core part of the required solution. (See section: "Invoking Lambda functions using Amazon SNS notifications").