Node.js startup pattern

/**
 * Copyright (c) TySoft Limited 2014 - ALL RIGHTS RESERVED.
 */

'use strict';

var Url = require('url'),
    Async = require('async'),
    Express = require('express'),
    Passport = require('passport'),
    ExpressApp = Express(),
    Connect = require('connect'),
    MongoStore = require('connect-mongo')(Express),
    HttpServer = require('http').createServer(ExpressApp),
    Config = require('./config/config'),
    DatabaseConfig = require('./config/config-database');

var session_store = null;

Async.waterfall([
    // Environment configuration
    function (done) {
        done(Config.checkConfig());
    },
    // Connect to the database
    function (done) {
        DatabaseConfig.configDatabase(done);
    },
    // Configure express
    function (done) {

        // Store sessions in MongoDB
        session_store = new MongoStore({
            host: DatabaseConfig.database.host,
            port: DatabaseConfig.database.port,
            db: DatabaseConfig.database.name,
            username: DatabaseConfig.database.username,
            password: DatabaseConfig.database.password
        });

        // Configure a public static content server
        ExpressApp.use(Express.static(__dirname + '/client' + (Config.inProduction() ? '-build' : '')));

        // Use compress to automatically gzip requests and responses
        ExpressApp.use(Express.compress());

        // Enable cookie parsing, needed for our sessions
        ExpressApp.use(Express.cookieParser());

        // Enable body parsing so we can access the request body as an object
        ExpressApp.use(Connect.urlencoded());
        ExpressApp.use(Connect.json());

        // Make sure we set the session cookie on subdomains in prod so it can be accessed on the socket domain
        var cookie_domain = null;
        if (Config.inProduction()) {
            var server_url = Url.parse(Config.getConfig(Config.keys.server_url)),
                parts = server_url.hostname.split('.');
            cookie_domain = '.' + parts[parts.length - 2] + '.' + parts[parts.length - 1];
        }

        // Enable sessions
        ExpressApp.use(Express.session({
            cookie: { domain: cookie_domain},
            key: Config.getConfig(Config.keys.session_key),
            secret: Config.getConfig(Config.keys.session_secret),
            store: session_store
        }));

        // Use passport for authentication
        ExpressApp.use(Passport.initialize());
        ExpressApp.use(Passport.session());

        // Development specific configuration
        ExpressApp.configure('development', function () {
            ExpressApp.use(Express.errorHandler({
                dumpExceptions: true,
                showStack: true
            }));
        });

        // Production specific configuration
        ExpressApp.configure('production', function () {
            ExpressApp.use(Express.errorHandler());
        });

        done();
    },
    // Configure passport
    function (done) {
        require('./config/config-authentication').config(ExpressApp, done);
    },
    // Configure socket.io
    function (done) {
        var SocketConfig = require('./config/config-sockets');
        SocketConfig.configureSockets(HttpServer, session_store);
        done();
    },
    // Start express server
    function (done) {

        var server_listening = false;

        HttpServer.once('error', function (err) {
            if (!server_listening) {
                done(err);
            }
        });

        HttpServer.once('listening', function () {
            server_listening = true;
            done();
        });

        HttpServer.listen(Config.getConfig(Config.keys.port));
    },
    // Load http controllers
    function (done) {
        require('./authentication/authentication-controller')(ExpressApp);
        require('./users/user-controller')(ExpressApp);
        require('./games/game-controller')(ExpressApp);
        require('./stories/story-controller')(ExpressApp);
        done();
    }],
    // Handle any errors encountered during startup
    function (err) {
        if (!err) {
            console.log('Poker server startup complete.');
        } else {
            console.log('Something went wrong during server startup. Exiting.');
            throw err;
        }
    }
);