aws_handler.js

// begin lambda connection
const { MongoClient } = require('mongodb');
const process = require('node:process');

// Get the URI for the cluster and use AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY
// from the environment, then set the appropriate auth options. Note that MongoClient
// now auto-connects so no need to store the connect() promise anywhere and reference it.
const client = new MongoClient(process.env.MONGODB_URI, {
  authSource: '$external',
  authMechanism: 'MONGODB-AWS'
});

module.exports.handler = async function () {
  const databases = await client.db('admin').command({ listDatabases: 1 });
  return {
    statusCode: 200,
    databases: databases
  };
};
// end lambda connection

module.exports.client = client;