We will build a Lambda function to filter an AWS IoT Button message. This message is parsed on an event  from the handler function. To store a message into AWS DynamoDB, we use the putItem() function from the DynamoDB object with the passing JSON message.

The following is the complete program for the AWS Lambda function:

var AWS = require('aws-sdk');
var ddb = new AWS.DynamoDB();

exports.handler = (event, context, callback) => {
 
 var params = {
 TableName: 'aws-iot-button-db',
 Item: {
 'msg-id': {S:new Date().getTime().toString()},
 'CLICKED' : {S:event.clickType},
 'BUTTON_ID' : {S:event.serialNumber},
 }
 };
 
 // Call DynamoDB to add the item to the table
 ddb.putItem(params, function(err, data) {
 if (err) {
 callback(err, 'Error');
 } else {
 callback(null, 'Success');
 }
 });
};

Once done, please save all the programs.

We are done writing a program for AWS Lambda. Next, we will test it using AWS IoT Button.