AWS Certified Developer – Associate (DVA-C02) — Question 539

A developer is designing an event-driven architecture. An AWS Lambda function that processes data needs to push processed data to a subset of four consumer Lambda functions. The data must be routed based on the value of one field in the data.

Which solution will meet these requirements with the LEAST operational overhead?

Answer options

• A. Create an Amazon Simple Queue Service (Amazon SQS) queue and event source mapping for each consumer Lambda function. Add message routing logic to the data-processing Lambda function.
• B. Create an Amazon Simple Notification Service (Amazon SNS) topic. Subscribe the four consumer Lambda functions to the topic. Add message filtering logic to each consumer Lambda function. Subscribe the data-processing Lambda function to the SNS topic.
• C. Create a separate Amazon Simple Notification Service (Amazon SNS) topic and subscription for each consumer Lambda function. Add message routing logic to the data-processing Lambda function to publish to the appropriate topic.
• D. Create a single Amazon Simple Notification Service (Amazon SNS) topic. Subscribe the four consumer Lambda functions to the topic. Add SNS subscription filter policies to each subscription. Configure the data-processing Lambda function to publish to the topic.

Correct answer: D

Explanation

Using a single Amazon SNS topic with subscription filter policies allows the routing logic to be offloaded entirely to SNS, requiring zero custom routing code in the producer Lambda function. Options A and C increase operational overhead because they require custom routing logic to be maintained inside the data-processing Lambda function. Option B is inefficient and costly because all four consumer Lambda functions would be invoked for every message just to filter and potentially discard them.