RedisSMQ - Yet another simple Redis message queue

A simple high-performance Redis message queue for Node.js.

For more details about RedisSMQ design see https://medium.com/@weyoss/building-a-simple-message-queue-using-redis-server-and-node-js-964eda240a2a

Features

• Persistent: No messages are lost in case of a consumer failure.
• Atomic: A message is delivered only once to one consumer (in FIFO order) so you would never fall into a situation where a message could be processed more than once.
• High-performance message processing: See Performance for more details.
• Scalable: A queue can be consumed by many concurrent consumers, running on the same or on different hosts.
• Message expiration: A message will expire and not be consumed if it has been in the queue for longer than the TTL (time-to-live).
• Message consume timeout: The amount of time for a consumer to consume a message. If the timeout exceeds, message processing is cancelled and the message is re-queued to be consumed again.
• Delaying and scheduling message delivery: From version 1.0.19 a persistent scheduler has been built into RedisSMQ message queue. The scheduler accepts delaying messages, repeated messages delivery, period between repeats and CRON expressions.
• Highly optimized: No promises, no async/await, small memory footprint, no memory leaks. See callbacks vs promises vs async/await benchmarks.
• Monitorable: Statistics (input/processing/acks/unacks messages rates, online consumers, queues, etc.) are provided in real-time.
• Logging: Supports JSON log format for troubleshooting and analytics purposes.
• Configurable: Many options and features can be configured.
• Supports both redis & ioredis: Starting from v1.1.0 RedisSMQ can be configured to use either redis or ioredis to connect to Redis server.

Table of content

1. What's new?
2. Installation
3. Configuration
4. Usage
   1. Message Class
   2. Producer Class
   3. Consumer Class
5. Performance
   1. Scenarios
   2. Environment
   3. Results
6. Troubleshooting and monitoring
   1. Logs
   2. Monitoring
7. Contributing
8. License

What's new?

Starting from v2.0.0 TypeScript is now supported. Types definitions are include out of box. Also you can find an example about how to use RedisSMQ in a TypeScript project in the example folder.

Installation

npm install redis-smq --save

Considerations:

• Minimal Node.js version support is 7.0.0 (with --harmony flag), 7.6.0 (without --harmony flag). The latest stable Node.js version is recommended.
• Minimal Redis server version is 2.6.12.

Configuration

Before running a Producer or a Consumer instance, an object containing the configuration parameters can be supplied to the class constructor in order to configure the message queue.

A configuration object may look like:

'use strict';

const path = require('path');

module.exports = {
    namespace: 'my_project_name',
    redis: {
        driver: 'redis',
        options: {
            host: '127.0.0.1',
            port: 6379,
            connect_timeout: 3600000,
        },
    },
    /*
    // for old syntax bellow, the redis driver is used by default
    redis: {
        host: '127.0.0.1',
        port: 6379,
        connect_timeout: 3600000,
    },
    */
    log: {
        enabled: 0,
        options: {
            level: 'trace',
            /*
            streams: [
                {
                    path: path.normalize(`${__dirname}/../logs/redis-smq.log`)
                },
            ],
            */
        },
    },
    monitor: {
        enabled: true,
        host: '127.0.0.1',
        port: 3000,
    },
};

Parameters

• namespace (String): Optional. The namespace for message queues. It can be composed only of letters (a-z), numbers (0-9) and (-_) characters. Namespace can be for example configured per project.

• redis (Object): Optional. Redis client parameters. If used without redis.driver and redis.options, for backward compatibility, this parameter would be considered as holding redis driver options and therefor the redis driver would be used by default.

• redis.driver (String): Optional. Redis driver name. Can be either redis or ioredis.

• redis.options (Object): Optional. Redis driver options.

  • See https://github.com/NodeRedis/node_redis#options-object-properties for all valid parameters for redis driver.
  • See https://github.com/luin/ioredis/blob/master/API.md#new_Redis for all valid ioredis parameters.

• log (Object): Optional. Logging parameters.

• log.enabled (Integer/Boolean): Optional. Enable/disable logging. By default logging is disabled.

• log.options (Object): Optional. All valid Bunyan configuration options are accepted. Please look at the Bunyan Repository for more details.

• monitor (Object): Optional. RedisSMQ monitor parameters.

• monitor.enabled (Boolean/Integer): Optional. Enable/Disable the monitor. By default disabled.

• monitor.host (String): Optional. IP address of the monitor server. By default 0.0.0.0.

• monitor.port (Integer): Optional. Port of the monitor server. By default 7210.

Usage

RedisSMQ provides 3 classes: Message, Producer and Consumer in order to work with the message queue.

Message Class

Message class is the main component responsible for creating and handling messages. It encapsulates and provides all the required methods needed to construct and deal with messages.

const { Message } = require('redis-smq');

const message = new Message();

message
    .setBody({hello: 'world'})
    .setTTL(3600000)
    .setScheduledDelay(10)
    .setScheduledRepeat(6)
    .setScheduledPeriod(60)
    .setScheduledCron('* 30 * * * *');

let messageTTL = message.getTTL();

// same as 
messageTTL = message.getProperty(Message.PROPERTY_TTL);

See Message API Reference for more details.

Producer Class

Producer class is in turn responsible for producing messages.

Each producer instance has an associated message queue and provides produceMessage() method which handle the message and decides to either send it to the message queue scheduler or to immediately enqueue it for delivery.

// filename: ./example/test-queue-producer.js

'use strict';
const { Message, Producer } = require('redis-smq');

const message = new Message();

message
    .setBody({hello: 'world'})
    .setTTL(3600000)
    .setScheduledDelay(10);

const producer = new Producer('test_queue');
producer.produceMessage(message, (err) => {
   if (err) console.log(err);
   else console.log('Successfully produced')
});

See Producer API Reference for more details.

Consumer Class

The Consumer class is the base class for all consumers. All consumers extends this base class and implements consume() method which got called once a message is received.

Consumer classes are saved per files. Each consumer file represents a consumer class.

A consumer class may look like:

// filename: ./example/test-queue-consumer.js

'use strict';

const redisSMQ = require('redis-smq');

const Consumer = redisSMQ.Consumer;

class TestQueueConsumer extends Consumer {
    /**
     *
     * @param message
     * @param cb
     */
    consume(message, cb) {
        //  console.log('Got a message to consume:', message);
        //  
        //  throw new Error('TEST!');
        //  
        //  cb(new Error('TEST!'));
        //  
        //  const timeout = parseInt(Math.random() * 100);
        //  setTimeout(() => {
        //      cb();
        //  }, timeout);
        cb();
    }
}

TestQueueConsumer.queueName = 'test_queue';

const consumer = new TestQueueConsumer();
consumer.run();

To start consuming messages, a consumer needs first to be launched from CLI to connect to the Redis server and wait for messages:

$ node ./example/test-queue-consumer.js

Once a message is received and processed the consumer should acknowledge the message by invoking the callback function without arguments.

The message acknowledgment informs the message queue that the message has been successfully consumed.

If an error occurs, the message should be unacknowledged and the error should be reported to the message queue by calling the callback function. Failed messages are re-queued and delivered again unless message retry threshold is exceeded. Then the messages are moved to dead-letter queue (DLQ). Each message queue has a system generated corresponding queue called dead-letter queue where all failed to consume messages are moved to.

See Consumer API Reference for more details.

Performance

One key indicator about how RedisSMQ is fast and performant is Message throughput. Message throughput is the number of messages per second that the message queue can process.

Scenarios

We can measure the Producer throughput and the Consumer throughput. The benchmark is composed of:

1. Measuring Producer throughput (without consumers running at the same time)
2. Measuring Consumer throughput (without producers running at the same time)
3. Measuring throughput of Producer and Consumer both running at the same time

In all scenarios messages are produced and consumed as fast as possible.

Environment

The benchmark was performed on a KVM virtual machine (4 CPU cores, 8GB RAM) hosted on a desktop computer (CPU AMD FX8350, RAM 32GB) running Debian 8.

No performance tuning was performed for the VM, neither for Redis server. Default parameters were used out of box.

The virtual machine was setup to run a single instance of Redis (Redis is single threaded, so more instances can boost performance).

All consumers, producers, monitor and redis server are launched from the same host.

Results

Troubleshooting and monitoring

Logs

This package is using JSON log format, thanks to Bunyan.

The structured data format of JSON allows analytics tools to take place but also helps to monitor and troubleshoot issues easier and faster.

By default all logs are disabled. Logging can affect performance (due to I/O operations). When enabled you can use bunyan utility to pretty format the output.

Unless configured otherwise, the standard output is the console which launched the consumer.

$ node consumer | ./node_modules/.bin/bunyan

Monitoring

The RedisSMQ Monitor is an interface which let you monitor and debug your RedisSMQ server from a web browser in real-time.

Starting from version v1.1.0, RedisSMQ Monitor has split up into a standalone project and was packaged under RedisSMQ Monitor

RedisSMQ includes the monitor as part of its package.

// filename: ./example/monitor.js
'use strict';

const config = require('./config');
const { monitor } = require('redis-smq');

monitor(config).listen(() => {
    console.log('It works!')
});

Contributing

So you are interested in contributing to this project? Please see CONTRIBUTING.md.

License

MIT