index.js

/**
 * Launch cluster and workers.
 * React on SIGINT and SIGTERM.
 * restart worker if worker exit.
 */

'use strict';

require('dotenv').config();
const fs = require('fs');
const spawn = require('child_process').spawn;

if (!process.env.DEVEL && process.env.LOGFILE && !process.env.BACKGROUND) {
  var spawnArgvs = [];
  for (var i in process.argv) {
    if (i > 0) {
      spawnArgvs.push(process.argv[i]);
    }
  }
  var env = process.env;
  env.BACKGROUND = true;
  spawn(process.argv0, spawnArgvs, {
    stdio: 'ignore',
    detached: true,
    env: env,
  }).unref();
  process.exit();
}

if (process.env.DEVEL) {
  if (process.env.DEVEL_DEBUG) {
    process.env.DEBUG = process.env.DEVEL_DEBUG;
  } else {
    process.env.DEBUG = '*';
  }
}

if (process.env.BACKGROUND) {
  process.env.DEBUG_COLORS = false;
  var logFile = fs.createWriteStream(process.env.LOGFILE, { flags: 'a' });
  process.stdout.write = process.stderr.write = logFile.write.bind(logFile);
}

const cluster = require('cluster');
const WebHttp = require('./includes/web.js');
const debugF = require('debug');

/**
 * Constructor.
 *   Prepare data for deploy.
 */
function Cluster(data) {
  var self = this;
  self.data = data;

  if (cluster.isMaster) {
    if (data.pid) {
      fs.writeFileSync(data.pid + "", process.pid + "");
    }
    let numCPUs = 1;
    if (data.count) {
      numCPUs = data.count;
    } else {
      numCPUs = require('os').cpus().length;
    }

    self.debug.log('Starting up %s workers.', numCPUs);
    for (var i = 0; i < numCPUs; i++) {
      cluster.fork();
    }

    cluster.on('online', function(worker) {
      self.debug.log('Worker %s is online', worker.process.pid);
    });

    cluster.on('exit', function(worker, code, signal) {
      self.debug.log('Worker %s died. code %s signal %s', worker.process.pid, code, signal);
      self.debug.log('Starting a new worker');
      cluster.fork();
    });

    cluster.on('listening', function(worker, address) {
      if (self.data.callbacks['init']) {
        self.data.callbacks['init'](cluster, worker, address);
      }
    });

    process.on('SIGINT', function() {
      self.debug.log('Caught interrupt signal');
      if (data.pid) {
        fs.unlinkSync(data.pid);
      }
      process.exit();
    });
  } else {
    var webServer = new WebHttp(self.data);

    process.on('SIGINT', function() {
      self.debug.worker('Caught interrupt signal');
      webServer.stop();
    });

    process.on('SIGTERM', function() {
        self.debug.worker('Caught termination signal');
        webServer.stop();
      }
    );
  }
  return cluster;
}

Cluster.prototype.debug = {
  log: debugF('cluster:main'),
  worker: debugF('cluster:worker')
};

// Processed by tokens data structure
Cluster.prototype.data = {};

module.exports = Cluster;