Connecting Multiple Mongo DBs in a Node.js Project

Question

I am trying to connect multiple MongoDB databases into a single Node.js project. Here is my current structure and issue at hand.

Node Version: v6.12.1

Express.js Version: 4.16.2

Mongoose Version: 4.13.6

Current Structure:

primaryDB.js

 var mongoose = require('mongoose'); var configDB = require('./database.js'); //Connect to MongoDB via Mongoose mongoose.Promise = require('bluebird'); //mongoose.Promise = global.Promise; mongoose.connect(configDB.url, { useMongoClient: true }); //Check for successful DB connection var db = mongoose.connection; db.on('error', console.error.bind(console, 'connection error:')); db.once('open', function() { console.log("Primary DB Successfully Connected.."); }); module.exports = mongoose; 

secondaryDB.js

 var mongoose = require('mongoose'); mongoose.connect('mongodb://mongodb_address_goes_here:27017/db_name', { useMongoClient: true }); var db = mongoose.connection; db.on('error', console.error.bind(console, 'connection error:')); db.once('open', function() { console.log("Secondary DB Successfully Connected.."); }); module.exports = mongoose; 

Then each DB connection gets imported respectively into their schema files, from which the schema files have module exports.

Issue at hand

When I run my application it starts fine and connects to both DB's successfully however I believe that mongoose is either getting overwritten or something because I might be able to do a findOne() command on primary but secondary fails or vice versa.

Example:

 var async = require('async'); var primaryModel = require('../../../models/general/primary'); var SecondaryModel = require('../../../models/general/secondary'); function getInfo() { async.waterfall([ getPrimaryName, getSecondaryName ], function (err, info) { }); }; function getPrimaryName(callback){ Primary.findOne({}, function (err, primaryInfo){ if (err) { console.log("Error" + err); } console.log('Primary info is : ' + primaryInfo); callback(null,primaryInfo); }); } function getSecondaryName(primaryInfo, callback) { console.log(primaryInfo); //Make sure its being passed Secondary.findOne({}, function (err, secondaryInfo) { if (err) { console.log("Error" + err); } console.log('Secondary Info is : ' + secondaryInfo); callback(null, secondaryInfo); }); } 

The problem with above is I might get data back from the call to Primary but not Secondary. Which again I believe is from something being overridden .

Any help appreciated. Sorry about the verbosity.

Answer 1

use mongoose.createConnection to create your connections

so

const conn1 = mongoose.createConnection('first server options')
const conn2 = mongoose.createConnection('second server options')

read more here http://mongoosejs.com/docs/connections.html#multiple_connections