title: AWS Cognito - get user's sub in Lambda Trigger function
body: <p>Does someone know if it is possible in aws Cognito to get the user's 'sub' in one of the <a href="https://docs.aws.amazon.com/cognito/latest/developerguide/cognito-user-identity-pools-working-with-aws-lambda-triggers.html" rel="nofollow noreferrer">Lambda Trigger functions</a> you can use?
  (especially in <em>Pre Sign-Up</em> or <em>Post Confirmation</em>)</p>
  
  <p>Since it is recommended to use the 'sub' attribute as primary key it would be great to have access to it. </p>
  
  <p>Thank you!</p>