AWS- Data isn't saving to DynamoDB from Lambda

Question

My task is to add New Cognito Users to DynamoDB Using Lambda. I have been provided with an existing AWS Cognito User pool. So far, I have written a lambda function & testing it with demo data so that it can save the data into DynamoDB. But while testing, it doesn't save my data into the Database. For guidance, I have been following this article. In the article it is said that upon testing, my DynamoDB Table should be populated.

My lambda function looks like this:

const aws = require('aws-sdk');
const ddb = new aws.DynamoDB.DocumentClient({region: 'us-east-2'});


exports.handler = async (event, context) => {
    console.log(event);

    let date = new Date();

    const tableName = 'User';
    const region = 'us-west-2';
  
    
    console.log("table=" + tableName + " -- region=" + region);

    aws.config.update({region});


       
        let ddbParams = {
            Item: {
                'user_name': {S: event.request.userAttributes.user_name},
                'first_name': {S: event.request.userAttributes.first_name},
                'last_name': {S: event.request.userAttributes.last_name},
                'email_address': {S: event.request.userAttributes.email_address},
                'mobile_phone': {S: event.request.userAttributes.mobile_phone},
                'password': {S: event.request.userAttributes.password},
                'referred_by': {S: event.request.userAttributes.referred_by},
                'createdAt': {S: date.toISOString()}
            },
            TableName: tableName
        };

       
        try {
            await ddb.putItem(ddbParams).promise()
            console.log("Success");
        } catch (err) {
            console.log("Error", err);
        }

        console.log("Success: Everything executed correctly");
        context.done(null, event);


};

Sample input that I am testing with:

{
  "userName": "Proteeti Prova",
  "request": {
    "userAttributes": {
      "user_name": "Proteeti13",
      "first_name": "Proteeti",
      "last_name": "Prova",
      "email_address": "[email protected]",
      "mobile_phone": "7777777",
      "password": "ironman",
      "referred_by": "tony stark"
    }
  },
  "response": {}
}

Log output

START RequestId: XXXXXXXXXXXXXXXXXXXXXXXX Version: $LATEST 2020-10-23T07:59:49.334Z XXXXXXXXXXXXXXXXXXXXX INFO Error { ResourceNotFoundException: Requested resource not found at Request.extractError (/var/runtime/node_modules/aws-sdk/lib/protocol/json.js:51:27) at Request.callListeners (/var/runtime/node_modules/aws-sdk/lib/sequential_executor.js:106:20) at Request.emit (/var/runtime/node_modules/aws-sdk/lib/sequential_executor.js:78:10) at Request.emit (/var/runtime/node_modules/aws-sdk/lib/request.js:688:14) at Request.transition (/var/runtime/node_modules/aws-sdk/lib/request.js:22:10) at AcceptorStateMachine.runTo (/var/runtime/node_modules/aws-sdk/lib/state_machine.js:14:12) at /var/runtime/node_modules/aws-sdk/lib/state_machine.js:26:10 at Request. (/var/runtime/node_modules/aws-sdk/lib/request.js:38:9) at Request. (/var/runtime/node_modules/aws-sdk/lib/request.js:690:12) at Request.callListeners (/var/runtime/node_modules/aws-sdk/lib/sequential_executor.js:116:18) message: 'Requested resource not found', code: 'ResourceNotFoundException', time: 2020-10-23T07:59:49.233Z,
requestId: 'XXXXXXXXXXXXXXXXXXXXXXXXX',
statusCode: 400, retryable: false, retryDelay: 37.83355253768394 } 2020-10-23T07:59:49.335Z XXXXXXXXXXXXXXXXXXX INFO Success: Everything executed correctly END RequestId: XXXXXXXXXXXXXXXXXXXXXXXXXXXX REPORT RequestId: XXXXXXXXXXXXXXXXXXXXXXXXXXXX Duration: 1203.41 ms Billed Duration: 1300 ms Memory Size: 128 MB Max Memory Used: 89 MB Init Duration: 391.58 ms

Answer 1

So the ResourceNotFoundException means this, according to the AWS Doc:

You should double check if your table exists and if you you are using the right access key. In addition, why are you creating your DynamoDB object with us-east-2 as a region just to change it in your lambda to us-west-2. Try initiating the instance with the correct region right away.

Answer 2

Could you try with this code ?

const aws = require('aws-sdk');
aws.config.update({region: 'us-east-2'});
const ddb = new aws.DynamoDB.DocumentClient({apiVersion: '2012-08-10'});

exports.handler = async (event, context) => {
    console.log(event);

    let date = new Date();

    const tableName = 'User';
    const region = 'us-west-2';


    console.log("table=" + tableName + " -- region=" + region);

    aws.config.update({region});



        let ddbParams = {
            Item: {
                user_name:  event.request.userAttributes.user_name,
                first_name:  event.request.userAttributes.first_name,
                last_name:  event.request.userAttributes.last_name,
                email_address:  event.request.userAttributes.email_address,
                mobile_phone:  event.request.userAttributes.mobile_phone,
                password:  event.request.userAttributes.password,
                referred_by:  event.request.userAttributes.referred_by,
                createdAt:  date.toISOString()
            },
            TableName: tableName
        };


        try {
            await ddb.put(ddbParams).promise()
            console.log("Success");
        } catch (err) {
            console.log("Error", err);
        }

        console.log("Success: Everything executed correctly");
        context.done(null, event);


};

Issue seems coming for the putItem and also I advise you to use the documentClient with last version for more simplicity

Answer 3

Your problem is firstly, change your table name look your db name from the table section. Then enter the functions from aws console find your lambda function, basic settings > View your_lambda_function_name there are permissions and attach policy, create new policy for permissions give full access for dynamodb.