LambdaExecutionError from AWS CloudFront When Trying to do 301 Redirect with Lambda Function

Question

I’m trying to set up redirects on CloudFront using Lambda@Edge but I keep getting a vague error. Here’s my setup.

• I have a CloudFront distribution with behavior “redirect http to https”
• I have a Lambda function in us-east-1.
• When creating the function, I chose the “Basic Lambda@Edge permissions (for CloudFront trigger)” policy template.
• My Lambda function code is below.
• I tested my code in Lambda and there were errors.

When I click “Deploy to Lambda@Edge”,

• I choose my CloudFront distribution
• I choose “Viewer request” for CloudFront event (not sure if this is correct)
• I wait for the distribution status to change from “deploying” to a timestamp
• I invalidate my CloudFront cache using /* and wait for it to complete
• I verify the latest Lambda function version is associated with the CloudFront distribution under CloudFront behaviors

When I curl a URL,

• I get 503 “lambdaExecutionError from cloudfront”
• When I check the CloudWatch logs for the latest Lambda function version, it says “No data found”.

Any idea what might be causing the error?

• Is the format of my code’s response correct?
• Is “Viewer request” the correct “CloudFront event”?

export const handler = async (event, context) => {
    const { request, response } = event.Records[0].cf;

    var newLocation = "";
    var statusCode = 301;
    var statusDescription = "Moved Permanently";
    
    console.log(request);
    
    switch(request.uri) {
        case '/file1.pdf':
            newLocation = '/file2.pdf';
            statusCode = 301;
            break;
        case '/file3.pdf':
            newLocation = '/file4.pdf';
            statusCode = 301;
            break;
    }
    
    if (statusCode === 302) {
        statusDescription = "Found";
    }
    
    if (newLocation !== "") {
        response.headers['location'] = [
          {
            key: 'Location',
            value: newLocation,
          },
        ];
        
        return {
          status: statusCode,
          statusDescription: statusDescription,
          headers: response.headers,
        };
    } else {
        return response;
    }
};

Answer 1

I know you asked about Lambda@Edge, but have you considered implementing your redirect using CloudFront Functions? It's faster, cheaper, and a easier to configure in the Functions section of the CloudFront console. You can also test it out with different request URIs before deploying to ensure it's working.

Here's an example to get you going, you'll just need to update it slightly to match your use case - https://github.com/aws-samples/amazon-cloudfront-functions/tree/main/redirect-based-on-country