@knetik/micro-queue/dist/worker.js

const path = require('path');

const Core = require("@knetik/micro-core");

/**
 *
 * Each Job is configured with its own worker. The worker spawns threads as
 * needed and processes job instances in the background. The worker function is
 * transparent to the micro-core application and exists soulely to kick off the
 * Job class' perform function in the correct customer context.
 *
 * Worker config should include only what is required for processing a Job.
 * 1. *Do not include the queue adaptor in the worker env config.*
 * 2. *Do not attempt to create jobs inside a job.*
 *
 * - reset config to the worker env `${NODE_ENV}-worker`
 * - Core init
 * - Core connect by app_id -> App
 * - Get Job class from Adaptor.loadJobs
 * - Call Job.perform
 * - Returns the result of the job
 *
 * Keep in mind, We aren't handling errors. If you job crashes, we wont catch
 * it. This is another reason for the multi threaded worker design. If the
 * worker crashes, the micro core application does not.
 *
 * @name MicroQueueAdaptor#worker
 */
module.exports = job => {
  const {
    id,
    name,
    data: {
      app: { app_id, token, request_id },
      params
    }
  } = job;

  const { APP_ROOT, NODE_ENV = "local" } = process.env;
  const configPath = path.join(APP_ROOT, 'config', 'environments', NODE_ENV);

  /* eslint import/no-dynamic-require: 0 */
  const config = require(configPath);
  process.env.NODE_ENV = NODE_ENV.match('worker') ? NODE_ENV : config.WORKER_ENV || `${NODE_ENV}/worker`;

  const init = Core.initialized ? Promise.resolve.bind(Promise) : Core.init.bind(Core);

  return init(process.cwd()).then(() => Core.connect(app_id, token, request_id)).then(App => {
    App.Logger.info(`Performing Queued Job (${id})`, name, params);

    const Adaptor = require("./index");
    return Adaptor.loadJobs().then(jobs => {
      const Job = jobs[name];

      return Job.perform(App, params, job.progress.bind(job)).then(result => {
        job.progress(100);
        App.Logger.info(`Performing Queued Job (${id}): success`, name, result);

        return result;
      });
    });
  });
};