app1/node/app.js

const express = require('express');
const app = express();
const mongoose = require('mongoose');
const Schema = mongoose.Schema;
const database = 'mongodb://' + process.env.mongousr + ':' + process.env.mongopwd + '@mongo:27017/test';
const today = new Date();
var counter = 0;
const Prometheus = require('prom-client');
const fs = require('file-system');
const marked = require('marked');
const jwt = require('jsonwebtoken');
const bodyParser= require('body-parser');
const colors = require('colors');
const secret = 'wowmuchsecretveryhiddenwow'; 

// const morgan = require('morgan');
// use morgan to log requests to the console
// app.use(morgan('dev'));

// database connection (with retries)
const options = {
  autoIndex: false, // Don't build indexes
  reconnectTries:30, // Retry up to 30 times
  reconnectInterval: 500, // Reconnect every 500ms
  poolSize: 10, // Maintain up to 10 socket connections
  // If not connected, return errors immediately rather than waiting for reconnect
  bufferMaxEntries: 0,
  useNewUrlParser: true
}

const connectWithRetry = () => {
  console.log('MongoDB connection with retry')
  mongoose.connect(database, options).then(()=>{
    console.log('MongoDB is connected')
  }).catch(err=>{
    console.log('MongoDB connection unsuccessful, retry after 5 seconds.')
    setTimeout(connectWithRetry, 5000)
  })
}

const libCounter = new Prometheus.Counter({
  name: 'lib_invocation_count',
  help: 'A simple counter for app access during runtime created with prometheus nodejs library'
});

const libUptime = new Prometheus.Counter({
  name: 'lib_upTime',
  help: 'uptime A counter of the application\'s uptime in seconds created with prometheus nodejs library.'
})

console.log('mongousr: ', process.env.mongousr);
console.log('mongopwd: ', process.env.mongopwd);

// Prometheus Default Metrics collector
const collectDefaultMetrics = Prometheus.collectDefaultMetrics;
// Probe every 5th second.
collectDefaultMetrics({ timeout: 5000 });

// new schema model object based on the structure of what I want to put on MongoDB collection
var testSchema = new Schema({
  thingies: {
    type: String
  }
},{
  collection: 'test'
});

// new object that will hold the data using model structure made above
var thingies = mongoose.model('thingieName', testSchema);

// Default message for testing
app.get('/', (req, res)=>{
  res.json([{message:'yes, your nodejs app is really running'}]);
  counter++; // for prometheus invocation_count metric
  libCounter.inc(); // for prometheus lib_invocation_count metric
  console.log('Hello, I\'m inside endpoint \'/\''.green);
});

// Test endpoint for md files rendering
app.get('/test', function(req, res) {
  var path = '/app/README.md';
  var file = fs.readFileSync(path, 'utf8');
  res.send(marked(file.toString()));
});

// Prometheus metrics endpoint - Library
app.get('/metrics', function(req, res){
  libUptime.inc(Math.floor(process.uptime()));
  res.set('Content-Type', Prometheus.register.contentType)
  res.end(Prometheus.register.metrics())
  libUptime.reset();
});

// Prometheus metrics endpoint - Handmade
app.get('/metrics2', function(req, res){
  var now = new Date();
  var passedTime = now - today;
  res.writeHead(200, {'Content-Type':'text/plain'});
  res.write('# HELP uptime A counter of the application\'s uptime in millisenconds.' + '\n');
  res.write('# TYPE uptime counter' + '\n');
  res.write('uptime ' + passedTime + '\n');
  res.write('# HELP invocation_count A simple counter for app access during runtime' + '\n');
  res.write('# TYPE invocation_count counter'+ '\n');
  res.write('invocation_count ' + counter + '\n');
  res.end();
})

// JWT generation
app.use(bodyParser.urlencoded({ extended: false }));

app.post('/token', function(req, res) {

  const claims_power = { 
    username: req.body.username,
    password: req.body.password,
    subject: 'power#1234',
    issuer: 'http://youcantrustme.io',
    scope: 'admin' 
  };
  
  const claims_user = { 
    username: req.body.username,
    password: req.body.password,
    subject: 'normal_user',
    issuer: 'http://youcantrustme.io',
    scope: 'user' 
  };

  let token = '';

  switch(req.body.username) {
      case 'user1':
      if (req.body.password === 'pass1') {
          token = jwt.sign(claims_user, secret);
          console.log('JWT Token: ' + token);
          console.log(jwt.decode(token));
          // req.headers['access-token'] = token;
          res.redirect('http://localhost/yay.html');
      } else {
          res.redirect('http://localhost/nay.html');
      }
      break;
      case 'power':
      if (req.body.password === 'weak') {
          token = jwt.sign(claims_power, secret);
          console.log('JWT Token: ' + token);
          console.log(jwt.decode(token));
          // req.headers['access-token'] = token;
          res.redirect('http://localhost/yay.html');
      } else {
      res.redirect('http://localhost/nay.html');
      }
      break;
      default:
      res.status(500).send('User not found');
  } 
  console.log('http headers below:')
  console.log(req.headers);
});


// Restricted route
// const restrictedRoutes = express.Router();
// app.use('/restricted', restrictedRoutes);

// restrictedRoutes.use((req, res, next) => {
//   if (req.headers['access-token']) {
//     jwt.verify(req.headers['access-token'], secret), (err, decoded) => {
//       if (err) {
//         return res.json({ message: 'invalid token' });
//       } else {
//         req.decoded = decoded;
//         next();
//       }
//     }
//   } else {
//     res.status(500).send('no token found');
//   }
// });

// Restricted endpoint
// restrictedRoutes.get('/restricted', (req, res) => {
//   res.json([{secret:'you can see this message if you have access'}])
// });

// Mongo query
app.get('/info', function(req, res){
  thingies.find({}).then(function (thingies) {
    res.json(thingies);
  });
});


// Mongo insert
app.post('/info/add/:name', function(req, res){
  var item = {thingies: req.params.name};
  var data = new thingies(item);
  data.save();
  res.send('thingie ' + req.params.name + ' added to database' + '\n');
});

connectWithRetry();

app.listen(3001, () => {
  console.log('Server running on port 3001');
  console.log('process.env.PORT: ' + process.env.PORT);
});