Bug in s3-java example

[anarwal]

S3-java example to rename file uses incorrect destination bucket name here: https://github.com/awsdocs/aws-lambda-developer-guide/blob/master/sample-apps/s3-java/src/main/java/example/Handler.java#L54

It should be:
String dstBucket = srcBucket + "-resized";

Otherwise it ends up using srcBucket as desBucket and Lambda function runs in loop causing below error:
If your Lambda function uses the same bucket that triggers it, it could cause the function to execute in a loop. For example, if the bucket triggers a function each time an object is uploaded, and the function uploads an object to the bucket, then the function indirectly triggers itself. To avoid this, use two buckets, or configure the trigger to only apply to a prefix used for incoming objects.

[mwunderl]

Hi Abhimanyu,

This is the key part:
To avoid this, use two buckets, or configure the trigger to only apply to a prefix used for incoming objects.

The CloudFormation template in the sample app configures an Amazon S3 notification that only applies to object keys prefixed with inbound/: s3-java/template.yml

This prevents the function from running unless an image is uploaded to the inbound folder. It won't invoke itself in a loop.

I'll add this detail to the README.

Thanks,
-Michael

[anarwal]

Got it, makes sense. I was not using CloudFormation template but my own Terraform implementation and ended up having this issue. Thank you for the clarification.