Aws Cognito: How to assign user to a user group when user signs up

Question

I have below user groups in aws cognito. Admin Member Paid member

I want to assign all user to Member user group as default when they sign up on my application so I can assign different IAM role on that user group.

How do I assign user to a user group programmatically?

Solution

I found that I can use adminAddUserToGroup to add user to the specific group you have set on AWS Cognito. http://docs.aws.amazon.com/AWSJavaScriptSDK/latest/AWS/CognitoIdentityServiceProvider.html#adminAddUserToGroup-property

Comments

[0x6C38]

by any chance do you know if a lambda that makes use of that API must have permissions to a cognito pool resource or to an identity pool?

[Jeff Voss]

this api is non-intuitive as the user has to be already created in order to call it, I wonder if a Post confirmation lambda trigger would be better?

[Travis Delly]

Post confirmation lambda trigger doesn't run if the user was created via adminCreateUser, therefore using a post confirmation hook would not work. I'm currently using postAuthentication, but my biggest issue is i'm using a SQL Database which means when the instance isn't warm, it may take longer then usually to get my user.