Lambda functions do not trigger after cognito events - vue.js

Question

I'm trying to implement an authentication workflow using AWS Cognito in order to sync my users table (Hasura graphql backend) with Cognito users, but the post confirmation Lambda does not trigger. The code of the Lambda function is as follow:
const axios = require('axios');
exports.handler = async (event,context,callback) => {
console.log(event);
const id=event.request.userAttributes.sub;
const name=event.request.userAttributes.username;
const email=event.request.userAttributes.email;
const hasuraAdminSecret="####"
const graphAPI="####"
const body = {
query: `
mutation insertUsers($userId: String!, $userName: String!, $userEmail: String!) {
insert_users(objects: {cognito_id: $userId, email: $userEmail, username: $userName}) {
affected_rows
}
}
`,
variables: {
userId:id,
userEmail:name,
userName:email
}
}
var response = {};
await axios.post(graphAPI, body, {
headers: {'content-type' : 'application/json', 'x-hasura-admin-secret': hasuraAdminSecret}
})
.catch(err => {
console.error(err.data);
response=err.data;
})
.then(res => {
console.log(res.data);
response = res.data;
})
callback(null,event);
}
The code for the signup and the confirmation pages are as follow:
import { Auth } from 'aws-amplify';
export default {
name:'Signin',
data(){
return {
username: undefined,
email: undefined,
password: undefined,
code: undefined,
user: undefined,
}
},
methods: {
confirm() {
// After retrieveing the confirmation code from the user
Auth.confirmSignUp(this.username, this.code, {
// Optional. Force user confirmation irrespective of existing alias. By default set to True.
forceAliasCreation: false
}).then(this.$router.push("/"))
.catch(err => console.log(err));
},
signup(){
Auth.signUp({
username:this.username,
password: this.password,
attributes: {
email: this.email,
name:this.username
},
validationData: [], // optional
})
.then(data => this.user = data.user)
.catch(err => console.log(err));
}
}
}
When signing up the user is created and confirmed in the AWS console, but the lambda function is not triggered (no logs in Cloudwatch and no errors from Cognito). Where should I look ?

Answer 1

Once the new user signup through aws-cognito you can call lambda functions using trigger
Step 1: Open your aws-cognito User Pools under general setting click on trigger
Step 2: You can customise the workflow with triggers. You can call your lambda function
Pre sign-up
Pre authentication
Custom message
Post authentication
Post confirmation
Define Auth Challenge
Create Auth Challenge
Verify Auth Challenge
User Migration
Pre Token Generation
Step 3: Select your workflow trigger Post confirmation and you can see the list of lambda functions. You have to select the lambda function.
Adding Cloudwatch:
Step 1: You have add role under Configuration under Permissions tab
Step 2: Edit the role and attach policy for CloudWatch and CloudWatch Logs