Sample Code showing how you can use the kubernetes-pod-ip-finder to connect to a MongoDB Replica Set

mongodb-replica-set-using-pod-ip.js

/*
	Copyright 2016, Google, Inc.
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
 You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

 Unless required by applicable law or agreed to in writing, software
 distributed under the License is distributed on an "AS IS" BASIS,
 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 See the License for the specific language governing permissions and
 limitations under the License.
*/

var MongoClient = require('mongodb').MongoClient;
var express = require('express');
var request = require('request');

var app = express();
var url = 'localhost';

var errorMsg = function(db, res, txt){
	res.write(txt);
	res.end();
}

var insertDoc = function(db, res) {
	var date = new Date();
	db.collection('test').insertOne( {"time":date.toDateString()}, function(err, result) {
		if(err != null) errorMsg(db, res, " - Failed to write Data - " + err);
		else{res.write(" - Wrote Data"); findDocs(db, res);}
	});
};

var findDocs = function(db, res) {
	var cursor =db.collection('test').find( );
	cursor.each(function(err, doc) {
		if(err != null) errorMsg(db, res, " - Failed to read Data - " + err);
		else if (doc != null) res.write(" - " + JSON.stringify(doc));
		else {db.close();res.end();}
	});
};

var drop = function(db, callback) {
	db.collection('test').drop( function(err, response) {
		callback();
	});
};

var options = {
	db: {
		readPreference: 'nearest',
		slaveOk: true
	},
	replSet: {
		replicaSet: 'rs0'
	},
	server: {
		w: 2,
		autoReconnect: true
	}
};

//Ping Cluster for IP addresses of MongoDB Replica Sets
setInterval(function(){
	request('http://kubernetes-pod-ip-finder?role=mongo', function (error, response, body) {
		if (!error && response.statusCode == 200) {
			url = 'mongodb://'+JSON.parse(body).join()+'/test_?';
		}
	}) 
}, 5000);


app.get('/', function(req, res){
	res.writeHead(200, { 'Content-Type': 'application/json' });
	MongoClient.connect(url, options, function(err, db) {
		if(err != null) errorMsg(db, res, "Mongo DOWN");
		else{res.write("Mongo UP");insertDoc(db, res);}
	});
});

app.get('/clear', function(req, res){
	res.writeHead(200, { 'Content-Type': 'application/json' });
	MongoClient.connect(url, options, function(err, db) {
		if(err != null) errorMsg(db, res, "Mongo DOWN");
		else drop(db, function(){errorMsg(db, res, "Database Dropped");});
	});
});

app.listen(3000);