BullMQ: Premium Message Queue for NodeJS Based on Redis

BullMQ

The fastest, most reliable, Redis-based distributed queue for Node. Carefully written for rock solid stability and atomicity.

The gist

Install:

$ yarn add bullmq

Add jobs to the queue:

import { Queue } from 'bullmq';

const queue = new Queue('Paint');

queue.add('cars', { color: 'blue' });

Process the jobs in your workers:

import { Worker } from 'bullmq';

const worker = new Worker('Paint', async job => {
  if (job.name === 'cars') {
    await paintCar(job.data.color);
  }
});

Listen to jobs for completion:

import { QueueEvents } from 'bullmq';

const queueEvents = new QueueEvents('Paint');

queueEvents.on('completed', ({ jobId }) => {
  console.log('done painting');
});

queueEvents.on('failed', ({ jobId, failedReason }: { jobId: string, failedReason: string }) => {
  console.error('error painting', failedReason);
});

This is just scratching the surface, check all the features and more in the official documentation

Feature Comparison

Since there are a few job queue solutions, here is a table comparing them:

Feature	Bullmq-Pro	Bullmq	Bull	Kue	Bee	Agenda
Backend	redis	redis	redis	redis	redis	mongo
Observables	✓
Group Rate Limit	✓
Group Support	✓
Parent/Child Dependencies	✓	✓
Priorities	✓	✓	✓	✓		✓
Concurrency	✓	✓	✓	✓	✓	✓
Delayed jobs	✓	✓	✓	✓		✓
Global events	✓	✓	✓	✓
Rate Limiter	✓	✓	✓
Pause/Resume	✓	✓	✓	✓
Sandboxed worker	✓	✓	✓
Repeatable jobs	✓	✓	✓			✓
Atomic ops	✓	✓	✓		✓
Persistence	✓	✓	✓	✓	✓	✓
UI	✓	✓	✓	✓		✓
Optimized for	Jobs / Messages	Jobs / Messages	Jobs / Messages	Jobs	Messages	Jobs

---

🛠 Tutorials

You can find tutorials and news in this blog: https://blog.taskforce.sh/

Official FrontEnd

Supercharge your queues with a professional front end:

• Get a complete overview of all your queues.
• Inspect jobs, search, retry, or promote delayed jobs.
• Metrics and statistics.
• and many more features.

Sign up at Taskforce.sh

Used by

Some notable organizations using BullMQ:

Read the documentation

---

🚀 Sponsor 🚀

If you need high quality production Redis instances for your BullMQ project, please consider subscribing to RedisGreen, leaders in Redis hosting that works perfectly with BullMQ. Use the promo code "BULLMQ" when signing up to help us sponsor the development of BullMQ!

Contributing

Fork the repo, make some changes, submit a pull-request! Here is the contributing doc that has more details.

Thanks

Thanks for all the contributors that made this library possible, also a special mention to Leon van Kammen that kindly donated his npm bullmq repo.

Download Details:

Author: Taskforcesh
Source Code: https://github.com/taskforcesh/bullmq 
License: MIT license

#javascript #node #redis 

What is GEEK

Buddha Community

Redis Transactions & Long-Running Lua Scripts

Redis offers two mechanisms for handling transactions – MULTI/EXEC based transactions and Lua scripts evaluation. Redis Lua scripting is the recommended approach and is fairly popular in usage.

Our Redis™ customers who have Lua scripts deployed often report this error – “BUSY Redis is busy running a script. You can only call SCRIPT KILL or SHUTDOWN NOSAVE”. In this post, we will explain the Redis transactional property of scripts, what this error is about, and why we must be extra careful about it on Sentinel-managed systems that can failover.

Transactional Nature of Redis Lua Scripts

Redis “transactions” aren’t really transactions as understood conventionally – in case of errors, there is no rollback of writes made by the script.

“Atomicity” of Redis scripts is guaranteed in the following manner:

• Once a script begins executing, all other commands/scripts are blocked until the script completes. So, other clients either see the changes made by the script or they don’t. This is because they can only execute either before the script or after the script.
• However, Redis doesn’t do rollbacks, so on an error within a script, any changes already made by the script will be retained and future commands/scripts will see those partial changes.
• Since all other clients are blocked while the script executes, it is critical that the script is well-behaved and finishes in time.

The ‘lua-time-limit’ Value

It is highly recommended that the script complete within a time limit. Redis enforces this in a weak manner with the ‘lua-time-limit’ value. This is the maximum allowed time (in ms) that the script is allowed to run. The default value is 5 seconds. This is a really long time for CPU-bound activity (scripts have limited access and can’t run commands that access the disk).

However, the script is not killed when it executes beyond this time. Redis starts accepting client commands again, but responds to them with a BUSY error.

If you must kill the script at this point, there are two options available:

• SCRIPT KILL command can be used to stop a script that hasn’t yet done any writes.
• If the script has already performed writes to the server and must still be killed, use the SHUTDOWN NOSAVE to shutdown the server completely.

It is usually better to just wait for the script to complete its operation. The complete information on methods to kill the script execution and related behavior are available in the documentation.

#cloud #database #developer #high availability #howto #redis #scalegrid #lua-time-limit #redis diagram #redis master #redis scripts #redis sentinel #redis servers #redis transactions #sentinel-managed #server failures

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BullMQ: Premium Message Queue for NodeJS Based on Redis

BullMQ

The fastest, most reliable, Redis-based distributed queue for Node. Carefully written for rock solid stability and atomicity.

The gist

Install:

$ yarn add bullmq

Add jobs to the queue:

import { Queue } from 'bullmq';

const queue = new Queue('Paint');

queue.add('cars', { color: 'blue' });

Process the jobs in your workers:

import { Worker } from 'bullmq';

const worker = new Worker('Paint', async job => {
  if (job.name === 'cars') {
    await paintCar(job.data.color);
  }
});

Listen to jobs for completion:

import { QueueEvents } from 'bullmq';

const queueEvents = new QueueEvents('Paint');

queueEvents.on('completed', ({ jobId }) => {
  console.log('done painting');
});

queueEvents.on('failed', ({ jobId, failedReason }: { jobId: string, failedReason: string }) => {
  console.error('error painting', failedReason);
});

This is just scratching the surface, check all the features and more in the official documentation

Feature Comparison

Since there are a few job queue solutions, here is a table comparing them:

Feature	Bullmq-Pro	Bullmq	Bull	Kue	Bee	Agenda
Backend	redis	redis	redis	redis	redis	mongo
Observables	✓
Group Rate Limit	✓
Group Support	✓
Parent/Child Dependencies	✓	✓
Priorities	✓	✓	✓	✓		✓
Concurrency	✓	✓	✓	✓	✓	✓
Delayed jobs	✓	✓	✓	✓		✓
Global events	✓	✓	✓	✓
Rate Limiter	✓	✓	✓
Pause/Resume	✓	✓	✓	✓
Sandboxed worker	✓	✓	✓
Repeatable jobs	✓	✓	✓			✓
Atomic ops	✓	✓	✓		✓
Persistence	✓	✓	✓	✓	✓	✓
UI	✓	✓	✓	✓		✓
Optimized for	Jobs / Messages	Jobs / Messages	Jobs / Messages	Jobs	Messages	Jobs

---

🛠 Tutorials

You can find tutorials and news in this blog: https://blog.taskforce.sh/

Official FrontEnd

Supercharge your queues with a professional front end:

• Get a complete overview of all your queues.
• Inspect jobs, search, retry, or promote delayed jobs.
• Metrics and statistics.
• and many more features.

Sign up at Taskforce.sh

Used by

Some notable organizations using BullMQ:

Read the documentation

---

🚀 Sponsor 🚀

If you need high quality production Redis instances for your BullMQ project, please consider subscribing to RedisGreen, leaders in Redis hosting that works perfectly with BullMQ. Use the promo code "BULLMQ" when signing up to help us sponsor the development of BullMQ!

Contributing

Fork the repo, make some changes, submit a pull-request! Here is the contributing doc that has more details.

Thanks

Thanks for all the contributors that made this library possible, also a special mention to Leon van Kammen that kindly donated his npm bullmq repo.

Download Details:

Author: Taskforcesh
Source Code: https://github.com/taskforcesh/bullmq 
License: MIT license

#javascript #node #redis 

How to Install NodeJS on Ubuntu 19.04

Overview
In this tutorial, you will learn how to install Node onto Ubuntu 19.04 Disco Dingo. We will cover installation from the default repositories and, for those wanting more recent releases, how to install from the NodeSource repositories.

Installing from Ubuntu
The Ubuntu 19.04 Disco Dingo repository includes NodeJS version 10.15. Like most packages found here, it certainly is not the most recent release; however, if stability is more important than features, it will be your preferred choice.

#nodejs #nodejs 10.x #nodejs 11.x #nodejs 12.x #nodejs 8.x

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