MongoDB-Lambda-Example

lambda-mongodb-example

'use strict'
const AWS = require('aws-sdk');
var MongoClient = require('mongodb').MongoClient;

let atlas_connection_uri;

exports.handler = (event, context, callback) => {
    var uri = process.env['MONGODB_ATLAS_CLUSTER_URI'];
    
    if (atlas_connection_uri != null) {
        processEvent(event, context, callback);
    } 
    else {
        const kms = new AWS.KMS();
        kms.decrypt({ CiphertextBlob: new Buffer(uri, 'base64') }, (err, data) => {
            if (err) {
                console.log('Decrypt error:', err);
                return callback(err);
            }
            atlas_connection_uri = data.Plaintext.toString('ascii');
            processEvent(event, context, callback);
        });
    } 
};

function processEvent(event, context, callback) {
    console.log('Calling MongoDB Atlas from AWS Lambda with event: ' + JSON.stringify(event));
    var jsonContents = JSON.parse(JSON.stringify(event));
    
    //date conversion for grades array
    if(jsonContents.grades != null) {
        for(var i = 0, len=jsonContents.grades.length; i < len; i++) {
            //use the following line if you want to preserve the original dates
            //jsonContents.grades[i].date = new Date(jsonContents.grades[i].date);
            
            //the following line assigns the current date so we can more easily differentiate between similar records
            jsonContents.grades[i].date = new Date();
        }
    }
    
    try 
    {
		MongoClient.connect(atlas_connection_uri, function(err, db) 
        {
			createDoc(db,  jsonContents, callback);
		});
    } 
    catch(err) 
    {
        console.error('an error occurred', err);
    }
}

function createDoc (db, json, callback) {
  db.collection('restaurants').insertOne( json, function(err, result) {
      if(err!=null) {
          console.error("an error occurred in createDoc", err);
          callback(null, JSON.stringify(err));
      }
      else {
        console.log("Kudos! You just created an entry into the restaurants collection with id: " + result.insertedId);
        callback(null, "SUCCESS");
      }
    db.close();
  });
};