DynamoDB Trigger Lambda Function PROBLEM: Function call failed

Question

I enabled streams on my dynamoDB table. As items are modified, a lambda function is triggered. I think I set up everything correctly both on the lambda trigger side, permissions, and dynamodb side. I also ran my lambda function with test data and it succeeded. However, when items are modified in the table, the trigger did not start my lambda function. Instead, I got the following error:

Batch size: 100 Last processing result: PROBLEM: Function call failed

Any idea what's the best way to debug this? I went on CloudWatch logs but there were no logs associated with the trigger/stream.

Thanks.

Edit: Logs for the lambda function (not its dynamodb trigger). The trigger didn't generate any log statements.

START RequestId: 3a08eedc-f0de-11e8-9008-033b48d2cb67 Version: $LATEST  18:16:28 END RequestId: 3a08eedc-f0de-11e8-9008-033b48d2cb67  18:16:28 REPORT RequestId: 3a08eedc-f0de-11e8-9008-033b48d2cb67 Duration: 81.85 ms Billed Duration: 100 ms Memory Size: 128 MB Max Memory Used: 30 MB

Answer 1

I ran into this issue today.

1. I debugged it by manually triggering the lambda with the Test button on the top of the main lambda page. It showed the error output trying to run my lambda.
2. The reason I had an error was the handler parameter as I had a non-standard javascript function name and I forgot to configure that in my lambda.