Connect to mongodb with replica sets using native driver and allow testing of failover via web interface

mongo_replica_test.js

var mongo = require('mongodb'),
    Server = mongo.Server,
    ReplSetServers = mongo.ReplSetServers,
    http = require('http'),
    inspect = require('util').inspect
;

var replSet = new ReplSetServers([
    new Server('1.1.1.1', 27017, {auto_reconnect: true}),
    new Server('2.2.2.2', 27017, {auto_reconnect: true}),
    new Server('3.3.3.3', 27017, {auto_reconnect: true})
    ],
    {rs_name: 'rs1'}
);

var client, collection;
var cool_kids = ['Andrew', 'Jake', 'Mark', 'Pin-Bo', 'Bob', 'Chris', 'Sabo', 'Leonard'];

var db = new mongo.Db('repltest', replSet);

var server = http.createServer(function(req, res) {
    if (req.url != '/query' && req.url != '/insert') {
        return res.end();
    }

    req.on('data', function(chunk) {
        console.log("data received: "+chunk);
    });

    req.on('end', function() {
        if (req.url === '/insert') {
            var i = Math.floor(Math.random()*cool_kids.length);
            collection.insert({name: cool_kids[i]}, {safe: true}, function(err, docs) {
                if (err) return res.end(err);
                return res.end('Added '+cool_kids[i]+' to the cool_kids collection');
            });
        } else { // query
            collection.find({}).toArray(function(err, docs) {
                if (err) return res.end(err);
                return res.end(inspect(docs));
            });
        }
    });

});

server.listen(10000, function(err) {

    function open() {
        db.open(function(err, client_) {
            if (err) console.error("db.open err: "+err);
            client = client_;
            client.dropDatabase(function(err, done) {
                if (err) console.error("dropDatabase err: "+err);
                client.createCollection('cool_kids', function(err, collection_) {
                    if (err) console.error("createCollection err: "+err);
                    collection = collection_;
                    collection.insert({name: 'Andrew'}, {safe: true}, function(err, docs) {
                        if (err) console.error("insert err: "+err);
                    });
                });
            });
        });
    }
    db.on('timeout', function(replSet) {
        console.error("Err: server timeout");
    });
    db.on('close', function(replSet) {
        var err = new Error('close err');
        console.error("Err: server close: "+err.stack);
    });

    open();
});