cognito-idp UserPool id format does not match AWS format

[georgealton]

The format for a Cognito UserPool Id produced by the the cognito-idp mock does not produce ids in the expected format for a Cognito UserPool - The ids produced are uuids. The format for the Id field of a UserPool is documented as

Id

The ID of the user pool.

Type: String

Length Constraints: Minimum length of 1. Maximum length of 55.

Pattern: [\w-]+_[0-9a-zA-Z]+

Required: No

https://docs.aws.amazon.com/cognito-user-identity-pools/latest/APIReference/API_UserPoolType.html

So a uuid isn't a valid representation of an Id

This can be reproduced by

import moto
import boto3

create_pool_kwargs = {
            "PoolName": "test_pool",
            "Schema": [
                {
                    "Name": "email",
                    "AttributeDataType": "String",
                    "Required": True,
                    "Mutable": True,
                },
                {
                    "Name": "tenant_id",
                    "AttributeDataType": "String",
                    "Mutable": False,
                },
            ],
            "AdminCreateUserConfig": {
                "AllowAdminCreateUserOnly": True,
                "UnusedAccountValidityDays": 1,
            },
        }


def set_up_tear_down_user_pool():
    cognito_idp = boto3.client('cognito-idp')
    pool = cognito_idp.create_user_pool(**create_pool_kwargs)
    pool_id = pool['UserPool']['Id']
    print(pool_id)
    cognito_idp.delete_user_pool(UserPoolId=pool_id)


# with moto
with moto.mock_cognitoidp() as mock_cognito:
    set_up_tear_down_user_pool()

# without
set_up_tear_down_user_pool()

Produces:

eb9ef17e-acea-4a95-8440-7ee79dd1f172
eu-west-1_qtdBQSSL4

The general expectation is that the pool_id is in the format "{region}_{id}". I usually use the region part when attempting to determine, from a pool id, the region that pool is available in.

I'm using the package installed via pip and python mocks.

moto==1.3.4
botocore==1.10.52
boto3==1.7.3