How to get current user username in AWS Lambda?

Question

I use AWS Lambda + Cognito (User Pool + Federated Identity) + API Gateway. Users authenticate in WEB application with amazon-cognito-identity-js and invokes API with aws-api-gateway-client. API Gateway methods have AWS_IAM authorizer. How to get username (from User Pool) in Lambda function?

Answer 1

You can use event.identity.username

exports.handler = async (event, _, callback) => {
   try {
        console.log('event', event);
        console.log('event.identity.username', event.identity.username);
        const userId = event.identity.username;
        console.log('userId', userId);

        callback(null, true);
   } catch(e) {
       console.log(e);
       callback(e);
   }
};