How do I look up a cognito user by their sub/UUID?

Question

I want to look up a user in my Cognito user pool by their sub, which as far as I can tell, is just their UUID. I would like to do this in Java within a Lambda function but c

Answer 1

Old question, but you the username parameter is overloaded in Cognito's adminGetUser method. It is, unfortunately, not documented: adminGetUser SDK

Here's a snippet:

const params = {
  UserPoolId: 'someUserPoolId'
  Username: 'random-string-sub-uuid',
};

CognitoService.adminGetUser(params,(err, data) => {
  console.log(data);
})

Returns:
{ Username: 'random-string-sub-uuid',
  UserAttributes:
   [ { Name: 'sub', Value: 'random-string-sub-uuid' },
     { Name: 'custom:attributeName', Value: 'someValue' },
     { Name: 'email_verified', Value: 'false' },
     { Name: 'name', Value: 'nameValue' },
     { Name: 'email', Value: 'user@stackoverflow.com' } ],
  UserCreateDate: 2018-10-12T14:04:04.357Z,
  UserLastModifiedDate: 2018-10-12T14:05:03.843Z,
  Enabled: true,
  UserStatus: 'CONFIRMED' }