faktory-worker

A node.js client and worker library for the Faktory job server. The client allows you to push jobs and communicate with the Faktory server and the worker fetches background jobs from the Faktory server and processes them.

Faktory server compatibility: ~v1.0.0

Installation

npm install faktory-worker

Usage

Pushing jobs

const faktory = require('faktory-worker');

(async () => {
  const client = await faktory.connect();
  await client.job('ResizeImage', { id: 333, size: 'thumb' }).push();
  await client.close(); // remember to disconnect!
})().catch(e => console.error(e));

A job is a payload of keys and values according to the faktory job payload specification. Any keys provided will be passed to the faktory server during PUSH. A jid (uuid) is created automatically for your job when using this library. See the spec for more options and defaults.

Processing jobs

const faktory = require('faktory-worker');

faktory.register('ResizeImage', async ({ id, size }) => {
  const image = await Image.find(id);
  await image.resize(size);
});

faktory.work();

A job function can be a sync or async function. Simply return a promise or use await in your async function to perform async tasks during your job. If you return early or don't await properly, the job will be ACKed when the function returns.

faktory.work() traps INT and TERM signals so that it can gracefully shut down and finish any in-progress jobs before the options.timeout is reached.

Middleware

const faktory = require('faktory-worker');

faktory.use(async (ctx, next) => {
  const start = Date.now();
  await next();
  const ms = Date.now() - start;
  console.log(`${ctx.job.jobtype} took ${ms}ms`);
});

faktory.work();

Faktory middleware works just like koa middleware. You can register a middleware function (async or sync) with .use. Middleware is called for every job that is performed. Always return a promise, await next(), or return next(); to allow execution to continue down the middleware chain.

CLI

faktory-worker comes with two helper scripts:

node_modules/.bin/faktory-work

Starts one worker. Use --help for more information.

and

node_modules/.bin/faktory-cluster

Worker Options

You can override the default options for a faktory worker by providing an object to the faktory.work() method or the Worker() constructor.

faktory.work({

  // default: 127.0.0.1 -- can be set in FAKTORY_URL env (see FAQ)
  host: '127.0.0.1',

  // default: 7419 -- can be set in FAKTORY_URL env
  port: 7419,

  // can be set in FAKTORY_URL env
  password: 's33kr3t',

  // default: 20, this is a max number of jobs the worker will have
  // in progress at any time
  concurrency: 5,

  // default: ['default'] the queues the worker will process
  queues: ['critical', 'default', 'eventually'],

  // default: 8000 the number of milliseconds jobs have to complete after
  // receiving a shutdown signal before the job is aborted and the worker
  // shuts down abruptly
  timeout: 25 * 1000,

  // default: uuid().first(8) the worker id to use in the faktory-server connection
  // for this process. must be unique per process
  wid: 'alpha-worker',

  // default: [] labels for the faktory worker process to see in the UI
  labels: [],
});

Debugging

Use DEBUG=faktory* to see related debug log lines.

FAQ

How do I specify the Faktory server location?

By default, it will connect to tcp://localhost:7419. Use FAKTORY_URL to specify the URL, e.g. tcp://faktory.example.com:12345 or use FAKTORY_PROVIDER to specify the environment variable which contains the URL: FAKTORY_PROVIDER=FAKTORYTOGO_URL. This level of indirection is useful for SaaSes, Heroku Addons, etc.

How do I access the job payload in my function?

The function passed to register can be a thunk. The registered function will receive the job args and if that function returns a function, that returned function will be called and provided the execution context (ctx) which contains the raw job payload at ctx.job, containing all custom props and other metadata of the job payload.

faktory.register('JobWithHeaders', (...args) => async ({ job }) => {
  const [ email ] = args;
  I18n.locale = job.custom.locale;
  log(job.custom.txid);
  await sendEmail(email);
});

How do I add middleware to the job execution stack?

Because many jobs may share the same dependencies, the faktory job processor holds a middleware stack of functions that will execute before the job function does. You can add middleware to this stack by calling faktory.use and providing a function to be called. The middleware execution in faktory-worker works exactly the same as koa.

Here's an example of passing a pooled connection to every faktory job that's executed.

const { createPool } = require('generic-pool'); // any pool or connection library works
const faktory = require('faktory');

const pool = createPool({
  create() { return new Client(); },
  destroy(client) { return client.disconnect(); }
});

faktory.use(async (ctx, next) => {
  ctx.db = await pool.acquire();
  try {
    // middleware *must* return next() or await next()
    // this invokes the downstream middleware (including your job fn)
    await next();
  } finally {
    // return connection to pool
    pool.release(ctx.db);
  }
});

faktory.register('TouchRecord', (id) => async ({ db }) => {
  const record = await db.find(id);
  await record.touch();
});

Roadmap

Development

Install docker.

bin/server will run the faktory server in a docker container. The server is available at localhost:7419

Use DEBUG=faktory* to see debug lines.

Tests

The tests can be run via npm test. They will be executed in parallel by ava.

Author

Josh Bielick, @jbielick

ecdemis123/faktory_worker_node