cluster-service/lib/worker-ready.js

Turns your single process code into a fault-resilient multi-process service with built-in REST & CLI support

var cservice = require("../cluster-service"),
  cluster = require("cluster"),
  util = require("util"),
  messageBus = require("./message-bus"),
  onWorkerStop = null;

module.exports = exports = workerReady;

function workerReady(options, forceIsWorker) {
  if (cluster.isMaster === true && forceIsWorker !== true) {
    return; // ignore if coming from master
  }

  if (cservice.locals.workerReady === true) {
    return; // ignore dup calls
  }

  if (options === false) {
    cservice.locals.workerReady = false;

    return; // do not continue
  }

  cservice.locals.workerReady = true;

  options = options || {};

  if (options.servers) {
    require("./net-servers").add(options.servers);
  }

  onWorkerStop = options.onWorkerStop;

  process.on("message", onMessageFromMaster);

  // allow worker to inform the master when ready to speed up initialization
  cservice.processSafeSend(process,
    messageBus.createMessage("workerReady", {
      onStop: (typeof options.onWorkerStop === "function")
    })
  );
}

function onMessageFromMaster(msg) {
  if (!messageBus.isValidMessage(msg) ||
    cservice.msgBus.processMessage(msg)) {
    return;
  }

  switch (msg.cservice.cmd) {
    case "onWorkerStop":
      cservice.netServers.close(function() {
        if (typeof onWorkerStop === "function") {
          // if custom handler is provided rely on that to
          // cleanup and exit process
          onWorkerStop();
        } else {
          // otherwise we can exit now that net servers have exited gracefully
          process.exit();
        }
      });
      break;
  }
}