CloudFront Functions vs Lambda@Edge

CloudFront Functions

• is a CloudFront native feature (code is managed entirely within CloudFront) and visible only on the CloudFront dashboard.
• supports lightweight functions written only in JavaScript language
• runs in Edge Locations
• has process-based isolation
• supports Viewer Request, Viewer Response trigger events only
  • Viewer Request: after CloudFront receives the request from the Viewer
  • Viewer Response: before CloudFront forwards the response to the Viewer
• supports sub-millisecond execution time
• scales to millions of requests/second
• as they are built to be more scalable, performant, and cost-effective, they have the following limitations
  • no network access
  • no file system access
• cannot access the request body

Lambda@Edge

• are Lambda functions and visible on the Lambda dashboard.
• supports Node.js and Python languages, currently
• runs in Regional Edge Caches
• has VM-based isolation
• supports Viewer Request, Viewer Response, Origin Request, and Origin Response trigger events.
  • Viewer Request: after CloudFront receives the request from the Viewer
  • Viewer Response: before CloudFront forwards the response to the Viewer
  • Origin Request: before CloudFront forwards the request to the Origin
  • Origin Response: after CloudFront receives the response from the Origin
• supports longer execution time, 5 seconds for viewer triggers and 30 seconds for origin triggers
• scales to 1000s of requests/second
• has network and file system access
• can access the request body

AWS Certification Exam Practice Questions

• Questions are collected from Internet and the answers are marked as per my knowledge and understanding (which might differ with yours).
• AWS services are updated everyday and both the answers and questions might be outdated soon, so research accordingly.
• AWS exam questions are not updated to keep up the pace with AWS updates, so even if the underlying feature has changed the question might not be updated
• Open to further feedback, discussion and correction.

1. You’ve been given the requirement to customize the content which is distributed to users via a CloudFront Distribution. The content origin is an S3 bucket and the customization attribute exists in the request body. How could you achieve this?
   1. Add an event to the S3 bucket. Make the event invoke a Lambda function to customize the content before rendering
   2. Use CloudFront Functions
   3. Use Lambda@Edge
   4. Use a separate application on an EC2 Instance for this purpose.

References

AWS_CloudFront_Functions_Lambda@Edge_Comparison