Is it possible to invoke a Lambda from an Architect Data Action without full admin rights?
I have the ARN and endpoint configured. The role has Lambda:Invoke attached. Architect returns 403 Forbidden immediately. I checked the CloudWatch logs, no execution trace. The policy looks standard.
{
"Version": "2012-10-17",
"Statement": [
{
"Effect": "Allow",
"Action": "lambda:InvokeFunction",
"Resource": "arn:aws:lambda:us-east-1:123456789:function:myFunc"
}
]
}
Any missing resource attributes or trust policy issues?
Make sure you check the Resource ARN format in your trust policy. The docs say “The resource string must match the function ARN exactly.” I copy-pasted the ARN but forgot the trailing asterisk. Without it, the permission fails silently. Architect returns 403 because the role cannot assume the execution context. I tested this locally and got the same error. The policy needs to allow sts:AssumeRole for the Genesys service principal, not just lambda:InvokeFunction.
{
"Effect": "Allow",
"Principal": {
"Service": "lambda.amazonaws.com"
},
"Action": "sts:AssumeRole"
}
Add this to the Lambda execution role. If you miss this, the Data Action times out or returns 403. I spent two days debugging this. The timeout setting in Architect does not fix IAM errors. You need the correct trust relationship first. Check the CloudTrail logs for UnauthorizedOperation. This usually points to missing trust policies. Do not rely on the 403 message alone. It is vague.
Ah, yeah, this is a known issue with the trust policy scope. is spot on about the resource arn, but there’s a second layer here that trips up most terraform deployments. if you are managing this via our standard cx as code pipelines, you likely missed the aws_iam_role_policy_attachment for the execution role itself, not just the trust relationship.
i just ran into this while promoting a staging build to prod. the 403 happens because the genesys platform tries to assume the role to invoke lambda, but the role doesn’t have the correct principal in its trust policy. you need to add the genesys service principal explicitly.
here is the minimal terraform block that fixes it. note the genesys.com principal. without this, the sts assume role fails silently from the architect side, resulting in that 403.
resource "aws_iam_role" "genesys_lambda_role" {
name = "genesys-lambda-exec-role"
assume_role_policy = jsonencode({
Version = "2012-10-17"
Statement = [
{
Action = "sts:AssumeRole"
Effect = "Allow"
Principal = {
Service = "lambda.amazonaws.com"
}
},
{
Action = "sts:AssumeRole"
Effect = "Allow"
Principal = {
AWS = "arn:aws:iam::123456789012:root" # replace with your genesys account id if using custom principal
}
}
]
})
}
resource "aws_iam_role_policy_attachment" "lambda_invoke" {
role = aws_iam_role.genesys_lambda_role.name
policy_arn = "arn:aws:iam::aws:policy/AWSLambdaExecute"
}
also double check your lambda function url or arn in the architect data action. if you are using the function url, ensure the auth type is AWS_IAM. if it is NONE, the role doesn’t matter and you get a different error, but if it is AWS_IAM and the role is wrong, you get the 403. i usually export the config via genesyscloud export to verify the payload matches before pushing to prod.
Make sure you check the resource ARN format in your trust policy. The suggestion above mentions the missing asterisk, but there is a subtle timing issue with IAM propagation that causes this 403 even after correcting the policy. When Genesys Cloud attempts to assume the role for the Data Action, AWS might not have fully replicated the new policy across all regions yet. I track these IAM assumption failures in Datadog using custom metrics from the /api/v2/analytics/api/usage endpoint to catch these propagation delays. You can add a small delay or retry logic in your deployment script, or manually verify the policy via the AWS CLI. Here is a quick check:
aws iam get-role-policy --role-name YourGenesysRole --policy-name YourPolicy
If the output matches your expectation but the 403 persists, wait 5-10 minutes. Also, ensure the Principal in the trust policy includes the specific Genesys service principal for your region, not just a wildcard. See more on IAM propagation delays in this support article: https://support.genesys.com/articles/iam-propagation-delays.