Question 1mediummultiple choice
Full question →mediummultiple choiceObjective-mapped
A developer configures an AWS Lambda function to process image files uploaded to an S3 bucket. The bucket receives a mix of .jpg, .png, and .pdf files. To reduce costs, the developer wants the Lambda function to be invoked only for image files (.jpg and .png). How should the developer configure the S3 event notification?
Answer choices
Why each option matters
Good practice is not just finding the correct option. The wrong answers often show the exact trap the exam wants you to fall into.
A
Distractor review
Configure the S3 event notification to invoke the Lambda function for all object create events, and add logic in the Lambda function to exit early if the object is not an image.
This approach still invokes the function for every upload, including PDFs, which incurs cost. The goal is to avoid unnecessary invocations entirely.
B
Best answer
Add a suffix filter to the S3 event notification that includes .jpg and .png.
S3 event notifications support filters based on object key patterns. Using a suffix filter restricts the notification to only objects ending with .jpg or .png, preventing Lambda invocations for other file types.
C
Distractor review
Set the S3 bucket policy to deny PutObject requests that do not have a .jpg or .png suffix.
Denying uploads of non-image files may not be desired. The requirement is to only invoke Lambda for images, not to block uploads of other file types.
D
Distractor review
Create two separate S3 buckets: one for images and one for other files, and configure the event notification only on the image bucket.
While this could work, it adds operational overhead. The simpler and more cost-effective solution is to use suffix filtering on the existing bucket.
Common exam trap
Common exam trap: ACLs stop at the first match
ACLs are processed top to bottom. The first matching entry wins, and an implicit deny usually exists at the end.
Technical deep dive
How to think about this question
ACL questions test precision: source, destination, protocol, port and direction. A generally correct ACL can still fail if it is applied on the wrong interface or in the wrong direction.
KKey Concepts to Remember
- Standard ACLs match source addresses.
- Extended ACLs can match source, destination, protocol and ports.
- The first matching ACL entry is used.
- There is usually an implicit deny at the end.
TExam Day Tips
- Check inbound versus outbound direction.
- Read the ACL from top to bottom.
- Look for a broader permit or deny above the intended line.
Related practice questions
Related DVA-C02 practice-question pages
Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.
More questions from this exam
Keep practising from the same exam bank, or move into a focused topic page if this question exposed a weak area.
Question 1
A developer is building a REST API using Amazon API Gateway that will serve static content from an Amazon S3 bucket. The API should cache responses for frequently accessed objects to reduce latency. Which API Gateway feature should the developer enable?
Question 2
A developer is running a web application on multiple Amazon EC2 instances behind an Application Load Balancer (ALB). The application needs to store user session state that must be available across all instances. The session data is small and temporary but must survive individual instance failures. Which AWS service should the developer use to store this session state?
Question 3
A developer has an AWS Lambda function that processes messages from an Amazon SQS standard queue. The function is idempotent and currently has a batch size of 10. The developer wants to increase throughput and increases the batch size to 100. After the change, CloudWatch metrics show a significant increase in throttles and the queue backlog is growing. The function's reserved concurrency is set to 10. What is the most effective action to resolve the throttling and improve throughput?
Question 4
A developer is managing an application running on Amazon EC2 instances behind an Application Load Balancer. Users report that the application becomes unresponsive after several hours, and restarting the instance temporarily fixes the issue. The developer suspects a memory leak but cannot add custom instrumentation. Which AWS service can collect memory utilization metrics and help identify the memory leak with minimal configuration?
Question 5
A developer is building a serverless web application using AWS Lambda and Amazon DynamoDB. The application needs to perform complex aggregations on data stored in DynamoDB. Which AWS service should the developer use to perform these aggregations efficiently without reading all the data into Lambda?
Question 6
A developer has an Amazon S3 bucket containing private user documents. The application must generate a time-limited URL for users to download their own documents without requiring the users to have AWS credentials. Which solution should the developer use?
FAQ
Questions learners often ask
What does this DVA-C02 question test?
Standard ACLs match source addresses.
What is the correct answer to this question?
The correct answer is: Add a suffix filter to the S3 event notification that includes .jpg and .png. — S3 event notifications support filtering by prefix and suffix. By specifying a suffix filter for .jpg and .png, the notification will only be sent for objects with those extensions. Filtering within the Lambda function still invokes the function for every upload, incurring costs. Changing the bucket policy or using a separate bucket is not necessary for this requirement.
What should I do if I get this DVA-C02 question wrong?
Then try more questions from the same exam bank and focus on understanding why the wrong options are tempting.
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