add mongo example

install/usr/share/swarmlab.io/sec/project/courses/example-helloworld/app/mongo.js

@@ -0,0 +1,109 @@
+var path = require('path');
+var app = require('express')();
+var http = require('http').Server(app);
+var io = require('socket.io')(http);
+const MongoClient = require('mongodb').MongoClient;
+
+
+app.get('/test', (req, res) => {
+
+		var user="swarmlab"
+		var pass="swarmlab"
+
+		/*
+		use admin
+		db.createUser(
+			 {
+				 user: "test1",
+				 pwd: 'newpass',      // Or  "<cleartext password>"
+				 roles: [ { role: "readWrite", db: "app_swarmlab" } ],
+				 authenticationRestrictions: [ {
+						clientSource: ["192.168.1.7"],
+						serverAddress: ["192.168.80.2", "192.168.80.3", "192.168.80.4"]
+				 } ]
+			 }
+		)
+		*/
+
+	 var mongourl = "mongodb://"+user+":"+pass+"@swarmlabmongo1:27017,swarmlabmongo2:27017,swarmlabmongo1:27017/app_swarmlab?replicaSet=rs0&authSource=admin&w=1"
+	 const OPTS = {
+			useNewUrlParser: true,
+			useUnifiedTopology: true,
+			//poolSize: 10,
+			tls: false
+		};
+
+		const client = new MongoClient(mongourl,OPTS);
+
+		client.on('serverDescriptionChanged', function(event) {
+			console.log('received serverDescriptionChanged');
+			console.log(JSON.stringify(event, null, 2));
+		});
+
+		client.on('serverHeartbeatStarted', function(event) {
+			console.log('received serverHeartbeatStarted');
+			console.log(JSON.stringify(event, null, 2));
+		});
+
+		client.on('serverHeartbeatSucceeded', function(event) {
+			console.log('received serverHeartbeatSucceeded');
+			console.log(JSON.stringify(event, null, 2));
+		});
+
+		client.on('serverHeartbeatFailed', function(event) {
+			console.log('received serverHeartbeatFailed');
+			console.log(JSON.stringify(event, null, 2));
+		});
+
+		client.on('serverOpening', function(event) {
+			console.log('received serverOpening');
+			console.log(JSON.stringify(event, null, 2));
+		});
+
+		client.on('serverClosed', function(event) {
+			console.log('received serverClosed');
+			console.log(JSON.stringify(event, null, 2));
+		});
+
+		client.on('topologyOpening', function(event) {
+			console.log('received topologyOpening');
+			console.log(JSON.stringify(event, null, 2));
+		});
+
+		client.on('topologyClosed', function(event) {
+			console.log('received topologyClosed');
+			console.log(JSON.stringify(event, null, 2));
+		});
+
+		client.on('topologyDescriptionChanged', function(event) {
+			console.log('received topologyDescriptionChanged');
+			console.log(JSON.stringify(event, null, 2));
+		});
+
+		client.connect(function(err, client) {
+			if(err) throw err;
+
+				const db = client.db('app_swarmlab');
+					db.collection('logs').find({}).toArray()
+						.then(item => {
+								console.log('item '+JSON.stringify(item))
+								for (let i in item) {
+									console.log(JSON.stringify('items' + item[i]))
+								 }
+							})
+		});
+
+		res.send('<h1>Hello world!</h1>');
+});
+
+io.on('connection', s => {
+      console.error('socket connection');
+
+   s.on('log', (data, room) => {
+      console.log('broadcast', data);
+  });
+
+});
+
+http.listen(8084, () => console.error('listening on http://localhost:8084/'));
+console.error('socket.io example');