Serverless - AWS Lamda with MongoDB Atlas Queries Not Running - node.js

Question

I've created an AWS account and want to use MongoDB Atlas with AWS Lambda.
The only dependency I've downloaded is mongodb locally.
npm install mongodb
Driver based connection string given from mongoDB Atlas for Nodejs is
var uri = "mongodb+srv://kay:myRealPassword#cluster0.mongodb.net/test";
MongoClient.connect(uri, function(err, client) {
const collection = client.db("test").collection("devices");
// perform actions on the collection object
client.close();
});
I think the connection is successful, because err parameter is NULL.
But I cannot figure out how to create collection, how to find results, how to insert documents.
I've tried this code
module.exports.hello = (event, context, callback) => {
var MongoClient = require('mongodb').MongoClient;
var uri = "mongodb+srv://kay:myRealPassword#cluster0.mongodb.net/test";
MongoClient.connect(uri, function(err, client) {
const collection = client.db("test").collection("devices");
collection.insert( { "msg" : "My First Document" } );
var results = client.db("test").collection("devices").find();
console.log(results);
client.close();
callback(null, { message: 'Go Serverless v1.0! Your function executed successfully!', event });
});
};
but it returns (in Windows console) a huge Object in JSON format, its like a configuration data (not a query result)
enter image description here
I'm executing this code locally by
sls invoke local --function hello

Answer 1

The general idea is to check if there is an error in the connection, the insert, and so on. Take at look at this error checking:
if (error) return 1;
There are more sophisticated methods, but for your case this should do the work.
This is a example of how it show look your script:
MongoClient.connect(uri, (error, client) => {
if (error) return 1; // Checking the connection
console.log('Connection Successful');
var db = client.db('mydb'); // Your DB
let newDocument = { "msg" : "My First Document" }; // Your document
db.collection('mycollection').insert(newDocument, (error, results) => { // Your collection
if (error) return 1; // Checking the insert
console.log('Insert Successful');
})
db.collection('mycollection')
.find({})
.toArray((error, accounts) => {
if (error) return 1; // Checking the find
console.log('Find Successful');
console.log(accounts);
return 0;
})
})
And you should have an output like this:
Connection Successful
Insert Successful
Find Successful
[ { _id: 5a857dd2c940040d85cbe5f2, msg: 'My First Document' } ]
If your output is not like this, well the missing log would point the place where you have your error.