Mongoose-Connection-Pool

This module allows you to maintain an arbitrary number of changing Mongoose connections. It was designed for applications in which an unknown number of MongoDB databases contain similar collections. In such a case, the application cannot define the connections up front; on the other hand it doesn't need to keep inactive connections alive indefinitely.

The getConnection(host, db) method returns a connection to the requested host and database if one has already been created, otherwise it creates a new connection and returns that. When instantiating a ConnectionPool an options object can be passed in, the defaults for which are:

{
  poolSize: 5, //The size of Mongoose's internal pool
  expiryPeriod: 300000, //The number of milliseconds after which a connection expires
  checkPeriod: 60000 //The frequency with which to check for expired connections
}

Example Usage:

In db.js:

var ConnectionPool = require('mongoose-connection-pool').ConnectionPool;

exports.connectionPool = ConnectionPool({
  poolSize: 3
});

In models.js:

var mongoose = require('mongoose'),
  Schema = mongoose.Schema,
  connectionPool = require('./db.js').connectionPool;

var carSchema = new Schema({
  color: String,
  doors: Number,
  horsepower: Number
});

exports.CarFactory = function(host, db) {
  var conn = connectionPool.getConnection(host, db);
  return conn.model('cars', carSchema);
};

In file1.js:

var CarFactory = require('./models.js').CarFactory,
  Car = CarFactory('localhost', 'my-garage'),
  car = new Car({
    color: 'yellow',
    doors: 2,
    horsepower: 25
  });

In file2.js:

var CarFactory = require('./models.js').CarFactory,
  Car = CarFactory('mongo.example.com', 'another-garage'),
  car = new Car({
	  color: 'blue',
	  doors: 4,
	  horsepower: 275
  });