MongoLab recommended mongoose connection options. More supported connections for the underlying Node Native driver can be found here: http://mongodb.github.io/node-mongodb-native/driver-articles/mongoclient.html#mongoclient-connect-options

mongoose-connection-options.js

// mongoose 3.8.x
var mongoose = require('mongoose');
// mongodb-uri 0.9.x
var uriUtil = require('mongodb-uri');
 
/* 
 * Mongoose by default sets the auto_reconnect option to true.
 * We recommend setting socket options at both the server and replica set level.
 * We recommend a 30 second connection timeout because it allows for 
 * plenty of time in most operating environments.
 */
var options = { server: { socketOptions: { keepAlive: 1, connectTimeoutMS: 30000 } }, 
                replset: { socketOptions: { keepAlive: 1, connectTimeoutMS : 30000 } } };       
 
/*
 * Mongoose uses a different connection string format than MongoDB's standard.
 * Use the mongodb-uri library to help you convert from the standard format to
 * Mongoose's format.
 */
var mongodbUri = 'mongodb://user:pass@host:port/db';
var mongooseUri = uriUtil.formatMongoose(mongodbUri);
 
mongoose.connect(mongooseUri, options);
var conn = mongoose.connection;             
 
conn.on('error', console.error.bind(console, 'connection error:'));  
 
conn.once('open', function() {
  // Wait for the database connection to establish, then start the app.                         
});

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