I am currently working with GitLab webhook to trigger a Lambda function through AWS API Gateway, which will trigger a CI pipeline in another repository. My question is whether it is possible to validate the value of the X-Gitlab-Token in header at the mapping template level and if the token is incorrect just don’t pass the request to Lambda. It should be done without invoking the any other Lambda function for validation

I’m looking for information is it even possible and if so what should be done for it (examples of mapping templates, etc.)