Singleton MongoDB connection in Node

Question

What is the best way to set up a singleton in Node for Mongodb? I tried the following code, but it does not work when making a lot of calls rapidly.

The singleton does not get set up before subsequent calls, and thus it tries opening too many connections and eventually fails. The below call works well for making infrequent calls.

Anyone have suggestions on the best practice here?

var db_singleon;

var getConnection= function getConnection(callback)
{
    if (db_singleton)
    { 
      callback(null,db_singleton);
    }
    else
    {
        var connURL = mongoURI; //set in env variables
        mongodb.connect(connURL,function(err,db){
            if(err)
                console.error("Error creating new connection "+err);
            else
            {
                db_singleton=db;    
                console.error("created new connection");
            }
            callback(err,db_singleton);
            return;
        });
    }
}

Kosmetika · Accepted Answer · 2015-04-20 10:04:42Z

3

node modules are singletons by theirselves, just make db module somewhere:

var mongo = require('mongojs');
var config = require('path/to/config');
var connection = mongo.connect(config.connection, config.collections);

module.exports = connection;

and then require('path/to/db') it in your models, etc.

answered Apr 20, 2015 at 10:04

Kosmetika

21.3k39 gold badges112 silver badges179 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Bob Aleena Over a year ago

This worked. I modified it a bit (i.e. I'm not currently using a config file), but the principle of this was exactly what I needed. Thanks @Kosmetika for the pattern!

Collectives™ on Stack Overflow

Singleton MongoDB connection in Node

1 Answer 1

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related