Unrecognizable Lambda Output Cognito

Question

I am trying to implement an auto confirm mechanism in AWS, I'm getting an error due to the Lambda response. I can't find the correct return type in the docs.

Lambda:

exports.handler = (event, context, callback) => {
    event.response.autoConfirmUser = true;
    context.succeed(event.response);
};

Exception:

Unrecognizable lambda output (Service: AWSCognitoIdentityProviderService; Status Code: 400; Error Code: InvalidLambdaResponseException; Request ID: 5c7a2436-0515-11e7-b971-41a89adf53ea)

Answer 1

As shown in the PreSignUp trigger example in Cognito developer guide, you should use context.done(null, event); or context.succeed(event); at the end of your trigger.

Cognito expects the complete event source back in response from your lambda triggers being invoked as part of different Cognito User Pools flows.

Answer 2

Ruby lambda people, all cognito wants back is the event object.

def lambda_handler(event:, context:)
    # TODO implement
    return event
end

Answer 3

Is very simple.

1. Create a Lambda Function with this code : example

   exports.handler = function(event, context) {
   
   /* This Lambda function returns a flag to indicate if a user should be auto-confirmed.
   Perform any necessary validations.Impose a condition that the minimum length of the
   username of 5 is imposed on all user pools. */
   
      if (event.userName.length < 5) {
         var error = new Error('failed!');
         context.done(error, event);
      }
   
   /* Access your resource which contains the list of emails of users who were invited to
   sign up. Compare the list of email IDs from the request to the approved list */
   
      if(event.userPoolId === "yourSpecialUserPool") {
         if (event.request.userAttributes.email in listOfEmailsInvited) {
              event.response.autoConfirmUser = true;
         }
      }
   
      // Return result to Cognito
      context.done(null, event);
   };
   

Note: Role: Lambda basic execution

2. Create the trigger from cognito console and select the function lambda.

TEST 3. Create the user with the API and DONE.