We’re trying to route some call metadata to an AWS Lambda function right after the IVR gathers the account number. The Architect flow uses a standard External Integration data action. I’ve got the IAM role attached to the Lambda execution role, and the trust policy points to the Genesys Cloud AWS account ID. When the flow hits the data action, the UI just spins for a few seconds then drops a 500 Internal Server Error in the debug trace. The payload never makes it to CloudWatch.
I’ve been walking through the permissions step by step. First, the Lambda function itself just logs the event for now. The handler returns a simple {"statusCode": 200, "body": "ok"} object. The IAM policy attached to the role grants lambda:InvokeFunction on the specific ARN. It looks like {"Effect": "Allow", "Action": "lambda:InvokeFunction", "Resource": "arn:aws:lambda:eu-west-2:123456789012:function:cxone-meta-sink"}. The trust policy allows sts:AssumeRole for the Genesys principal. That line reads {"Effect": "Allow", "Principal": {"AWS": "arn:aws:iam::987654321098:root"}, "Action": "sts:AssumeRole"}.
The data action config in Architect looks like this. I’m using the direct invocation endpoint since we don’t need API Gateway routing yet.
{ "url": "https://lambda.eu-west-2.amazonaws.com/2015-03-31/functions/arn:aws:lambda:eu-west-2:123456789012:function:cxone-meta-sink/invocations", "method": "POST", "headers": {"Content-Type": "application/json"}, "body": "{\"accountId\": \"${account.id}\"}" }
I’ve verified the region matches. eu-west-2 is London. The endpoint format matches the AWS docs for direct invocation. I’m passing the agent ID and account number in the body. The flow just fails. No 403 from AWS, just a blanket 500 from Genesys. I suspect the data action runner might be trying to assume a role that doesn’t exist in the Genesys environment, or the external integration config needs a specific IAM role ID in the platform settings.
Here’s what I’ve checked so far:
- Lambda is deployed in eu-west-2 and triggers fine via the AWS console test event
- IAM policy grants
lambda:InvokeFunctionon the exact function ARN - Trust policy allows
sts:AssumeRolefor the Genesys Cloud AWS account - Data action URL uses the correct AWS Lambda invocation endpoint format
- Request body is valid JSON with no trailing commas
- Platform external integration is set to “Unauthenticated” since the Lambda doesn’t require API Gateway auth yet
The debug trace shows the HTTP request leaves the Genesys runtime but never returns a response. Timeout seems unlikely since it fails in under two seconds. I’ve tried adding an X-Genesys-Request-ID header just to track it in CloudWatch, but nothing shows up. The IAM role definitely needs a logs:CreateLogGroup and logs:PutLogEvents permission for CloudWatch, which it has. I’m wondering if the data action runner expects the Lambda to be behind an API Gateway, or if there’s a specific IAM role configuration in the Genesys admin UI that I’m missing.
Any chance the external integration needs a pre-signed URL instead of direct Lambda invocation? I’ve seen older docs mention that, but the current REST API reference doesn’t say much about it. The documentation just points to the generic REST endpoint structure without covering IAM role binding for data actions.