AWS Certified Solutions Architect – Associate (SAA-C03) — Question 793

A company is designing an event-driven order processing system. Each order requires multiple validation steps after the order is created. An idempotent AWS Lambda function performs each validation step. Each validation step is independent from the other validation steps. Individual validation steps need only a subset of the order event information.

The company wants to ensure that each validation step Lambda function has access to only the information from the order event that the function requires. The components of the order processing system should be loosely coupled to accommodate future business changes.

Which solution will meet these requirements?

Answer options

• A. Create an Amazon Simple Queue Service (Amazon SQS) queue for each validation step. Create a new Lambda function to transform the order data to the format that each validation step requires and to publish the messages to the appropriate SQS queues. Subscribe each validation step Lambda function to its corresponding SQS queue.
• B. Create an Amazon Simple Notification Service (Amazon SNS) topic. Subscribe the validation step Lambda functions to the SNS topic. Use message body filtering to send only the required data to each subscribed Lambda function.
• C. Create an Amazon EventBridge event bus. Create an event rule for each validation step. Configure the input transformer to send only the required data to each target validation step Lambda function.
• D. Create an Amazon Simple Queue Service (Amazon SQS) queue. Create a new Lambda function to subscribe to the SQS queue and to transform the order data to the format that each validation step requires. Use the new Lambda function to perform synchronous invocations of the validation step Lambda functions in parallel on separate threads.

Correct answer: C

Explanation

Amazon EventBridge is the ideal service for loosely coupled, event-driven architectures because it allows you to filter and route events to multiple targets. By using the EventBridge input transformer, you can extract and restructure only the necessary parameters from the original event payload before sending it to each validation Lambda function. Options A and D introduce tight coupling and unnecessary overhead by requiring a custom Lambda function to handle the data transformation and routing, while Option B is incorrect because Amazon SNS message filtering can route messages but cannot transform the payload structure.