gistfile1.js

var mongo = require('mongodb');
var logger = require('logger');
logger.debug = console.log

function connect_to_mongo( config_name, master_config, raw, on_connect ) {
    if (raw){
        return create_connection( master_config[config_name]);
    }

    var mongo_wrapper = {
        refresh_connection : function(on_refresh) {
            logger.debug('Master config: ' + JSON.stringify(master_config));
            if( this.client ) this.client.close();
            var self = this;
            this.client = create_connection( master_config[config_name], on_refresh);
        },

        fetch_collection: function( collection_name, callback, action ) {
            this.client.collection( collection_name, function( error, collection ) {
                if( error ) {
                    this.check_for_dead_connection( error );
                    callback( null, error ); 
                } else {
                    action( collection );
                }
            });
        },

        check_for_dead_connection: function( error ) {
            if( error_indicates_dead_connection( error ) )
                notify_of_dead_connection( error );

            function error_indicates_dead_connection( error ) {
                if( !error ) return false;
                return error.message.indexOf( 'no open connections') || error.message.indexOf( 'connection closed' );
            }

            function notify_of_dead_connection( error ) {
                logger.error( error.stack );
                var mailer = require('mailer');
                var smtp_config = require('config-loader')(__dirname, '/../../nedules/config/smtp');
                mailer.send({ host: smtp_config.host,
                              port: smtp_config.port,
                              domain: '[127.0.0.1]',
                              to: smtp_config.lander.to,
                              from: smtp_config.lander.to,
                              subject: active_environment() + ' Dead Mongo Connection',
                              body: error.stack},
                            function(err){
                                if(err) {
                                    logger.error( 'Failed to send dead mongo email: ' + err.stack );
                                }
                            });
            }
        },
        ObjectID : mongo.ObjectID
    };

    mongo_wrapper.refresh_connection(on_connect);
    return mongo_wrapper;
};
module.exports.connect_to_mongo = connect_to_mongo

function create_connection( config, on_connect ){
    logger.debug('Connecting to mongo with server options: ' + JSON.stringify( config ) );
    var connection_handlers = { 'standalone': open_standalone_connection, 'replicaset': open_replicaset_connection };
    var db = connection_handlers[config['configuration_type']]( config[config['configuration_type']] );
    db.open(function(error, cb){
        console.log("here",error, cb);
        if(error) {
            console.log( "Failed to connect to " + config['configuration_type'] + " mongo: " + error.message );
            throw error;
        }
        if( on_connect ) on_connect();
    });

    return db;

    function open_standalone_connection( config ) {
        logger.debug('Connecting to standalone mongo with server options: ' + JSON.stringify( config ) );
        return new mongo.Db( config.db_name, new mongo.Server( config.host, config.port, config.options ));
    }

    function open_replicaset_connection( config ) {
        logger.debug('Connecting to replicaset mongo with server options: ' + JSON.stringify( config ) );
        var servers= [];
        for( var index in config['servers'] )
            servers.push( new mongo.Server(
                        config['servers'][index]['host'],
                        config['servers'][index]['port'],
                        config['servers'][index]['options']
                        ));
        var replSet = new mongo.ReplSetServers( servers, {rs_name:config['options']['rs_name']} );
        return new mongo.Db( config.db_name, replSet) ;
    }
}

function active_environment() {
    if( !process.argv || process.argv.length < 3 )
        return process.env.NODE_ENV;
    for( var index = 2; index < process.argv.length; index++ ) { if( process.argv[index].indexOf('env=') === 0 ) return process.argv[index].substr(4); }
    return process.env.NODE_ENV;
}

bc = {
    auth:{
        configuration_type: 'replicaset',
        replicaset: {
            db_name: 'auth',
            servers: [
                {host:'localhost',port:4000,options:{auto_reconnect:true}},
                {host:'localhost',port:4001,options:{auto_reconnect:true}}
                ,{host:'localhost',port:4002,options:{auto_reconnect:true}}
            ],

                options: {
                    rs_name: 'replset0',
                    read_secondary: true,
                    socketOptions: { timeout: 0, keepAlive: 1 }
                }

        },

        standalone: {
            db_name:'auth',
            host:'UAT-NJ-MONGO-01',
            port:36108,
            options:{
                auto_reconnect: true,
                poolSize: 3,
                socketOptions: { keepAlive: 1 }
            }
        }
    },

    session:{
        configuration_type: 'standalone',
        replicaset: {

            db_name: 'sessions',

            servers: [
            {host:'UAT-NJ-MONGO-01',port:36108,options:{auto_reconnect:true}},
            {host:'UAT-NJ-MONGO-02',port:36108,options:{auto_reconnect:true}}
            ,{host:'UAT-NJ-MONGO-03',port:36108,options:{auto_reconnect:true}}

            ],

                options: {
                    rs_name: 'LANDER',
                    read_secondary: true,
                    socketOptions: { timeout: 0, keepAlive: 1 }
                }

        },
        standalone: {
            db_name:'sessions',
            host:'UAT-NJ-MONGO-01',
            port:36108,
            options:{
                auto_reconnect: true,
                poolSize: 3,
                socketOptions: { keepAlive: 1 }
            }
        }
    },

    sso:{
        configuration_type: 'replicaset',
        replicaset: {

            db_name: 'sso',

            servers: [
            {host:'UAT-NJ-MONGO-01',port:36108,options:{auto_reconnect:true}},
            {host:'UAT-NJ-MONGO-02',port:36108,options:{auto_reconnect:true}}
            ,{host:'UAT-NJ-MONGO-03',port:36108,options:{auto_reconnect:true}}

            ],

                options: {
                    rs_name: 'LANDER',
                    read_secondary: true,
                    socketOptions: { timeout: 0, keepAlive: 1 }
                }

        },
        standalone: {
            db_name:'sso',
            host:'UAT-NJ-MONGO-01',
            port:36108,
            options:{
                auto_reconnect: true,
                poolSize: 3,
                socketOptions: { keepAlive: 1 }
            }
        }

    }

};