valence-connect/install/template/bin/www.js

Connect to Valence for requests coming from applications running in the Valence Portal

#!/usr/bin/env node

/**
 * Module dependencies.
 */
const app          = require('../app'),
  cluster      = require('cluster'),
  debug        = require('debug')('extemplate:server'),
  http         = require('http'),
  numCPUs      = require('os').cpus().length,
  winston      = require('winston'),
  isProduction = (process.env.NODE_ENV &&
          process.env.NODE_ENV.trim() === 'production') ? true : false;

let server, numWorkers;

/**
 * Get port from environment and store in Express.
 */
const port = normalizePort(process.env.PORT || 'VPORT');
app.set('port', port);

/**
 * Workers
 */
numWorkers = process.env.WEB_CONCURRENCY;

if (typeof numWorkers !== 'undefined') {
  numWorkers = parseInt(numWorkers, 10);
  if (isNaN(numWorkers)) {
    numWorkers = numCPUs;
  } else {
    if (numWorkers > numCPUs) {
      numWorkers = numCPUs;
    }
  }
} else {
  numWorkers = numCPUs;
}

/**
 * Cluster
 */
if (cluster.isMaster && isProduction && numWorkers !== 0) {
  winston.log('info', 'Available CPUs %d', numCPUs);
  winston.log('info', 'Master %d is running', process.pid);
  winston.log('info', 'Starting %d worker(s)', numWorkers);

  // Fork workers
  //
  for (let i = 0; i < numWorkers; i++) {
    cluster.fork();
  }

  // If a worker dies, log it to the console and start another worker
  //
  cluster.on('exit', function(worker, code, signal) {
    winston.log('warn', 'Worker %d died', worker.process.pid);
    cluster.fork();
  });

  // Log when a worker starts listening
  //
  cluster.on('listening', function(worker, address) {
    winston.log('info', 'Worker %d started', worker.process.pid);
  });
} else {
  /**
     * Create HTTP server.
     */

  server = http.createServer(app);

  /**
     * Listen on provided port, on all network interfaces.
     */

  server.listen(port);
  server.on('error', onError);
  server.on('listening', onListening);
}

/**
 * Normalize a port into a number, string, or false.
 * @param {string} val
 * @return {number|boolean} port or false
 */
function normalizePort(val) {
  const port = parseInt(val, 10);

  if (isNaN(port)) {
    // named pipe
    return val;
  }

  if (port >= 0) {
    // port number
    return port;
  }

  return false;
}

/**
 * Event listener for HTTP server "error" event.
 * @param {object} error
 */
function onError(error) {
  if (error.syscall !== 'listen') {
    throw error;
  }

  const bind = typeof port === 'string' ?
    'Pipe ' + port :
    'Port ' + port;

  // handle specific listen errors with friendly messages
  switch (error.code) {
    case 'EACCES':
      console.error(bind + ' requires elevated privileges');
      process.exit(1);
      break;
    case 'EADDRINUSE':
      console.error(bind + ' is already in use');
      process.exit(1);
      break;
    default:
      throw error;
  }
}

/**
 * Event listener for HTTP server "listening" event.
 */
function onListening() {
  const addr = server.address();
  const bind = typeof addr === 'string' ?
    'pipe ' + addr :
    'port ' + addr.port;
  debug('Listening on ' + bind);
}