Cognito - Error: Invalid UserPoolId format - node.js

Question

I am using AWS CDK to create a userpool and userpool client. I would like to be able to access the userpool id and userpool client id from a lambda once they have been created. I pass these two values to the lambda via environmental variables. Here is my code:
import { Construct } from 'constructs';
import {
IResource,
LambdaIntegration,
MockIntegration,
PassthroughBehavior,
RestApi,
} from 'aws-cdk-lib/aws-apigateway';
import {
NodejsFunction,
NodejsFunctionProps,
} from 'aws-cdk-lib/aws-lambda-nodejs';
import { Runtime } from 'aws-cdk-lib/aws-lambda';
import * as amplify from 'aws-cdk-lib/aws-amplify';
import {
aws_s3,
aws_ec2,
aws_rds,
aws_cognito,
aws_amplify,
Duration,
CfnOutput,
} from 'aws-cdk-lib';
export class FrontendService extends Construct {
constructor(scope: Construct, id: string) {
super(scope, id);
const userPool = new aws_cognito.UserPool(this, 'userpool', {
userPoolName: 'frontend-userpool',
selfSignUpEnabled: true,
signInAliases: {
email: true,
},
autoVerify: { email: true },
});
const userPoolClient = new aws_cognito.UserPoolClient(
this,
'frontend-app-client',
{
userPool,
generateSecret: false,
}
);
const bucket = new aws_s3.Bucket(this, 'FrontendStore');
const nodeJsFunctionProps: NodejsFunctionProps = {
environment: {
BUCKET: bucket.bucketName,
DB_NAME: 'hospoFEDB',
AWS_NODEJS_CONNECTION_REUSE_ENABLED: '1',
USER_POOL_ID: userPool.userPoolId,
USER_POOL_CLIENT_ID: userPoolClient.userPoolClientId,
},
runtime: Runtime.NODEJS_14_X,
};
const registerLambda = new NodejsFunction(this, 'registerFunction', {
entry: 'dist/lambda/register.js',
memorySize: 1024,
...nodeJsFunctionProps,
});
const registerIntegration = new LambdaIntegration(registerLambda);
const api = new RestApi(this, 'frontend-api', {
restApiName: 'Frontend Service',
description: 'This service serves the frontend.',
});
const registerResource = api.root.addResource('register');
registerResource.addMethod('POST', registerIntegration);
}
}
Here is my lambda function and how I intend to use the USER_POOL_ID and USER_POOL_CLIENT_ID env variables:
import {
CognitoUserPool,
} from 'amazon-cognito-identity-js';
export const handler = async (event: any, context: any) => {
try {
console.log(process.env.USER_POOL_ID);
console.log(process.env.USER_POOL_CLIENT_ID);
const userPool = new CognitoUserPool({
UserPoolId: process.env.USER_POOL_ID as string,
ClientId: process.env.USER_POOL_CLIENT_ID as string,
});
return {
statusCode: 200,
};
} catch (error) {
if (error instanceof Error) {
const body = error.stack || (JSON.stringify(error, null, 2) as any);
return {
statusCode: 400,
headers: {},
body: JSON.stringify(body),
};
}
return {
statusCode: 400,
};
}
};
The idea with this setup is that I would create a cognito user pool and client then be able to pass those id's directly down. Currently if I run this locally via sam local start-api it generates the following USER_POOL_ID : Frontenduserpool87772999. If I try and use this id in the new CognitoUserPool({... part of my lambda function I get the following error:
Error: Invalid UserPoolId format.
If I deploy the app however and execute the lambda function from the deployed environment with the exact same code I get a USER_POOL_ID that looks more like: us-east-1_HAjkUj9hP. This works fine and I do not get the error above.
Should I assume that I can not create a user pool locally and will always have to point to the deployed user pool?

Answer 1

Should I assume that I can not create a user pool locally and will always have to point to the deployed user pool
Yes. See the docs: start-api creates an emulated local API endpoint and Lambda for local testing. It does not deploy or emulate other resources.
You can reference previously deployed AWS resources by passing a JSON file with the deployed physical values using the --env-vars flag.