engine.js

// Configure logger
if (process.env.NODE_ENV === "production") require("./configs/logger");

var fs = require('fs');
var environment = process.env.NODE_ENV || 'development';
var config = JSON.parse(fs.readFileSync(process.cwd() + '/config.json', encoding='utf8'))[environment];
var QUEUE_DELAY = 300;

// Configure globals
GLOBAL.appConfig = function () {return config;};
GLOBAL.db = require('./models/index');
GLOBAL.queue = require('./lib/queue/index');
var OrderBook = require("./lib/order_book")

var processEvents = function () {
  GLOBAL.queue.Event.findNextValid(function (err, event) {
    if (err) return exit("Could not fetch the next event. Exitting...", err);
    if (!event) {
      return OrderBook.matchBuyOrders(function (err) {
        if (err) return exit("Error processing matches. Exitting...", err);
        setTimeout(processEvents, QUEUE_DELAY);
      });
    } else if (event.type === "cancel_order") {
      return processCancellation(event, function (err) {
        if (err) return exit("Error processing cancellation. Exitting...", err);
        setTimeout(processEvents, QUEUE_DELAY);
      });
    } else if (event.type === "add_order") {
      return processAdd(event, function (err) {
        if (err) return exit("Error processing add order. Exitting...", err);
        setTimeout(processEvents, QUEUE_DELAY);
      });
    }
  });
};

var processCancellation = function (event, callback) {
  var orderId = event.loadout.order_id;
  OrderBook.deleteOpenOrder(orderId, function (err, existentOrder) {
    if (!err) {
      event.status = "processed";
      event.save().complete(function (err) {
        if (err) {
          console.error("Could send event " + event.id, err);
          return callback(err);
        } else {
          if (!existentOrder) return callback();
          GLOBAL.queue.Event.addOrderCanceled({order_id: orderId}, function (err) {
            if (err) {
              console.error("Could not add order_cancel for event " + event.id + " order " + orderId, err);
            }
            return callback(err);
          });
        }
      });
    } else {
      console.error("Could not process event " + event.id, err);
      return callback(err);
    }
  });
};

var processAdd = function (event, callback) {
  var data = event.loadout;
  OrderBook.addOrder(data, function (err, order) {
    if (!err) {
      event.status = "processed";
      event.save().complete(function (err) {
        if (err) {
          console.error("Could send event " + event.id, err);
          return callback(err);
        } else {
          GLOBAL.queue.Event.addOrderAdded({order_id: order.external_order_id}, function (err) {
            if (err) {
              console.error("Could not add order_added for event " + event.id + " order " + order.id, err);
            }
            return callback(err);
          });
        }
      });
    } else {
      console.error("Could not process event " + event.id, err);
      return callback(err);
    }
  });
};

var exit = function (errMessage, err) {
  console.error(errMessage, err);
  process.exit();
};

processEvents();

console.log("processing events...");