annotated mongodb node.js driver replicaset connection example, please read the comments

db connector improved.js

module.exports = function(mediator) {

    var mongo           = require('mongodb'),
        Server          = mongo.Server,
        Db              = mongo.Db,
        ReplSet         = mongo.ReplSet,
        config          = require('../../config'),
        replSetName     = config.mongo.rsname,
        servers         = config.mongo.servers,
        dbName          = config.mongo.dbname;

    //create a connection on boot
    mediator.once('boot.ready', function() {

        //create replicaset servers array
        var replSetServers = [];
        servers.forEach(function(server) {
            replSetServers.push(new Server(server.ip, server.port));
        });

        //create a new replicaset
        var replSet = new ReplSet(replSetServers, { //http://mongodb.github.com/node-mongodb-native/markdown-docs/replicaset.html gives a different example where ReplSetServers is used instead of ReplSet, deprecated?
                rs_name         : replSetName, //the name of the replicaset to connect to.
                ha              : true, //turn on high availability --> I still have to test this, but so far its looking promising.
                haInterval      : 2000, //time between each replicaset status check
                reconnectWait   : 5000, //time to wait in miliseconds before attempting reconnect
                retries         : 1000, //number of times to attempt a replicaset reconnect. // --> how do I set this to unlimited?
                readPreference  : Server.READ_SECONDARY, //the prefered read preference (Server.READ_PRIMARY, Server.READ_SECONDARY, Server.READ_SECONDARY_ONLY)
                poolSize        : 4 //default poolSize for new server instances --> how do I determine the optimal pool size?
            });

        //create the database
        var db = new Db(dbName, replSet);

        //open a connection to the database
        db.open(function(err) {
            if (err) return mediator.emit('db.error', err);

            //event: database ready
            mediator.emit('db.ready', db);

        });

    });

};

routines db connector.js

module.exports = function(mediator) {

    var mongo           = require('mongodb'),
        Server          = mongo.Server,
        Db              = mongo.Db,
        ReplSet         = mongo.ReplSet,
        config          = require('../../config'),
        replSetName     = config.mongo.rsname,
        servers         = config.mongo.servers,
        dbName          = config.mongo.dbname;

    //create a connection on boot
    mediator.once('boot.ready', function() {

        //create replicaset servers array
        var replSetServers = [];
        servers.forEach(function(server) {
            replSetServers.push(new Server(server.ip, server.port, {
                auto_reconnect: true, //nullified by https://github.com/mongodb/node-mongodb-native/blob/master/lib/mongodb/connection/repl_set.js#L128 --> why is this forced off? does it still auto reconnect?
                readPreference: Server.READ_SECONDARY, //probably redundant, sets the read preference (Server.READ_PRIMAR, Server.READ_SECONDARY_ONLY, Server.READ_SECONDARY) --> should this even be set here?
                poolSize: 4 //probably redundant, number of connections in the connection pool --> should this even be set here, or in ReplSet creation?
            }));
        });

        //create a new replicaset
        var replSet = new ReplSet(replSetServers, { //http://mongodb.github.com/node-mongodb-native/markdown-docs/replicaset.html gives a different example where ReplSetServers is used instead of ReplSet, deprecated?
                rs_name         : replSetName, //the name of the replicaset to connect to.
                ha              : true, //turn on high availability --> I still have to test this, but so far its looking promising.
                haInterval      : 2000, //time between each replicaset status check
                reconnectWait   : 5000, //time to wait in miliseconds before attempting reconnect
                retries         : 1000, //number of times to attempt a replicaset reconnect. // --> how do I set this to unlimited?
                readPreference  : Server.READ_SECONDARY, //the prefered read preference (Server.READ_PRIMARY, Server.READ_SECONDARY, Server.READ_SECONDARY_ONLY)
                poolSize        : 4 //default poolSize for new server instances --> how do I determine the optimal pool size?
            });

        //create the database
        var db = new Db(dbName, replSet, {
            slaveOk: true, //is this still needed? same as readPreference?
            reaper: true //why is this not enabled by default? seems like a must have for HA etc.?
        });

        //open a connection to the database
        db.open(function(err) {
            if (err) return mediator.emit('db.error', err);

            //event: database ready
            mediator.emit('db.ready', db);

        });

    });

};