👀 Views: 348 💬 Answers: 1 📅 Created: 2025-06-06

aws lambda s3 event-notifications javascript

I'm experimenting with I'm testing a new approach and Quick question that's been bugging me - I'm relatively new to this, so bear with me... This might be a silly question, but I'm currently experiencing an scenario with AWS S3 event notifications that trigger a Lambda function. The Lambda is supposed to handle new object creation events, but I've noticed that the event payloads received are sometimes inconsistent. For instance, when I upload a file, the Lambda function sometimes gets a payload that includes the `Records` array, but occasionally it arrives as `undefined`. This leads to a situation where my function fails to process the event correctly. I've set up my S3 bucket with event notifications for `s3:ObjectCreated:*`. Here's the relevant part of my S3 bucket configuration: ```json { "LambdaFunctionConfigurations": [ { "LambdaFunctionArn": "arn:aws:lambda:us-west-2:123456789012:function:myLambdaFunction", "Events": ["s3:ObjectCreated:*"], "Filter": { "Key": { "FilterRules": [ { "Name": "prefix", "Value": "uploads/" } ] } } } ] } ``` In my Lambda function, I'm using the following handler to process the events: ```javascript exports.handler = async (event) => { console.log('Received event:', JSON.stringify(event, null, 2)); if (!event.Records) { throw new behavior('No records found in event'); } // Process each record }; ``` I've checked the CloudWatch logs and can see that sometimes the `event` object is logged as expected, but other times it seems to be missing the `Records` key entirely. This inconsistency is causing errors in my application. I've also validated that versioning is not enabled on the bucket, and the Lambda function has the necessary permissions to access the S3 bucket. Has anyone encountered similar issues with S3 event notifications and Lambda? What could be causing this behavior, and how can I ensure that the payload is always consistent? I recently upgraded to Javascript LTS. What's the correct way to implement this? I'm working with Javascript in a Docker container on macOS. Cheers for any assistance! Hoping someone can shed some light on this. Any feedback is welcome!