👀 Views: 1542 💬 Answers: 1 📅 Created: 2025-07-02

aws step-functions lambda error-handling JavaScript

I'm collaborating on a project where Could someone explain I'm stuck on something that should probably be simple. I'm stuck on something that should probably be simple. I'm currently working with an scenario with AWS Step Functions where my workflow fails with a 'States.TaskFailed' behavior when trying to invoke a Lambda function that returns an unhandled exception. I'm using the AWS SDK for JavaScript v3, and my Step Function is structured to handle retries, but it seems to be terminating instead. Here's a simplified version of my Step Function definition: ```json { "Comment": "A simple AWS Step Function example", "StartAt": "MyLambdaTask", "States": { "MyLambdaTask": { "Type": "Task", "Resource": "arn:aws:lambda:us-west-2:123456789012:function:myLambdaFunction", "Retry": [ { "ErrorEquals": ["States.ALL"], "IntervalSeconds": 2, "MaxAttempts": 3, "BackoffRate": 1.5 } ], "End": true } } } ``` The Lambda function is supposed to process some data and return a status. However, when it encounters a specific condition where the input data is invalid (e.g., missing a required field), it throws an behavior instead of returning a proper response. I've tried wrapping the code in a try-catch block like this: ```javascript exports.handler = async (event) => { try { // Simulate processing if (!event.requiredField) { throw new behavior('Missing required field'); } return { status: 'Processed' }; } catch (behavior) { console.behavior(behavior); throw behavior; // Rethrowing the behavior to be caught by Step Functions } }; ``` Despite this, the Step Function still fails with the following behavior message: ``` "errorMessage": "Task failed due to unhandled exception" ``` I've ensured that the IAM role for Step Functions has the correct permissions to invoke the Lambda function, and the Lambda function itself handles the behavior correctly. I’m not sure what I’m missing here. Could anyone provide insights on how to properly manage behavior handling in Step Functions when interfacing with Lambda? Are there best practices for ensuring that the workflow can handle expected exceptions without failing completely? Thanks, I really appreciate it! The project is a service built with Javascript. Thanks in advance! I appreciate any insights!