sns_error_notification

aws_lambda_python_error_emailer

This is a simple template you can add to your existing AWS Lambda python code so that it will email you details on your exceptions and errors.

You can use CloudWatch to alert on errors, but then you just know that something went wrong, not what went wrong.

I'm sure there are other ways to do this, but I didn't have luck finding them and getting the information I needed, so here's what I came up with.

Caveats

This could generate a LOT of email. I am not responsible for your email administrator's wrath. You could always set up a different subscriber to the SNS topic instead of directly emailing.

This won't report syntax errors when loading the code. Make it a best practice to run python3 -m py_compile lambda_function.py before deploying to python. For that matter, add some unit or doc tests.

It also won't catch errors with deployment of the lambda environment, which does happen from time to time.

It will also report errors even if a retry of the script succeeds. See AWS Lambda Retry Behavior for information on when it may automatically be retried.

Lastly, it won't catch issues with the SNS queue itself. If that isn't set up right, you won't get emails.

If you know a better way

Please share it. I'd love to hear it it. I want to see:

• The full stack trace
• The event received as input
• The context (or at least important parts)

Additionally, it needs to handle rates of thousands of executions per second.

Set Up

1. Configure an SNS topic.
2. Subscribe to the SNS topic using your email address.
3. Verify your subscription.
4. Rename your lambda_handler function.
5. Add the code from lambda_function.py to your function and make it the new handler.