AWS amplify cognito accessing pubsub with AccessToken, IdToken and RefreshToken - amazon-web-services

Question

I am using AWS amplify with Angular and I followed the instructions to setup Amplify, add backend and then auth.
I also created a user in cognito pool and used it to login in my angular app. I am able to see AccessToken, IdToken and RefreshToken in the browser network tab. As per the guide I have to use these to obtain the pool tokens using which I can get temporary aws credentials to access aws services. I want to access pubsub to show messages being sent to aws iot_core.
But I was unable to find any information of how exactly we use these 3 tokens to access AWS resources..? Can anybody shed some light on this?
async signIn() {
Auth.signIn('xxxxx', 'xxxxx')
.then(user => {
if (user.challengeName === 'NEW_PASSWORD_REQUIRED') {
const { requiredAttributes } = user.challengeParam; // the array of required attributes,
e.g ['email', 'phone_number']
Auth.completeNewPassword(
user, // the Cognito User Object
'xxx', // the new password
// OPTIONAL, the required attributes
{
email: 'xxxx#example.com',
}
).then(user => {
// at this time the user is logged in if no MFA required
console.log(user);
}).catch(e => {
console.log(e);
});
} else {
console.log("Connecting to AWS IoT...")
//Apply plugin with configuration
Amplify.addPluggable(new AWSIoTProvider({
aws_pubsub_region: 'us-east',
aws_pubsub_endpoint: 'wss://xxxxx-ats.iot.us-east-1.amazonaws.com/mqtt',
}));
console.log("hello")
}
}).catch(e => {
console.log(e);
});
}

Answer 1

As per the Amplify docs on PubSub you have to:
Create IAM policies for AWS IoT
Attach your policy to your Amazon Cognito Identity
Allow the Amazon Cognito Authenticated Role to access IoT Services
https://docs.amplify.aws/lib/pubsub/getting-started/q/platform/js/#step-1-create-iam-policies-for-aws-iot