I read some questions and answers about my issue, but I still don't know the answer.
Can I use the userSub in AWS Cognito as primary key?
AWS Cognito: Difference between Cognito ID and sub, what should I use as primary key?
First, I will try to describe my case.
I want to create an application with spring boot as a resource server that uses oauth2. Then to save me some time with user management, I was hoping to use AWS Cognito since it allows me to create users as admin. I can set it up that it won't let other people sign up for themselves, which is crucial for me since my app will have restricted access; the admin will manage that.
Now to my question, which field of AWS Cognito can I use as the primary key for keeping user-specific data in my DB? I read that neither usernamenor sub is correct.
username can be changed, for example, and sub is globally unique, so it can't be restored. Is there any way to create a custom field where AWS Cognito will autogenerate UUID that I can use, and if I had to restore the user pool, I would have an option to set this field?
You can still go with username. If it is ever changed, just update your database to reflect this change. You can also create a custom attributes in user pool. You can use that to store a self generated id. As for automatically generating this, you can have a post confirmation lambda trigger that will use adminUpdateUserAttributes to assign a unique id.