PHP实战RabbitMQ之延时队列篇

前言

延时队列的作用不再累述
本文使用rabbitmq的queue可以设置ttl时间，将到期的message设为死信，message会被push到delay_queue，消费delay_queue即可实现延时队列功能

场景

先假设这样一个场景：
小明在外卖平台下个一个订单，如果超过10分钟未支付，则系统自动取消订单，并推送给用户“订单已取消”信息。

开发思路：
下订单时就将订单orderId push到订单队列order_queue，并设置次条message的有效期为10分钟，当10分钟后此条message到期，会将此条message转化为死信push到exchange，将exchange和queue进行绑定，开一个/多个消费者消费queue，并判断queue中message订单是否已支付，若未支付则推送通知，取消订单。

流程图，未考虑消息消费失败的情况

核心代码

对RabbitMQ进行简单的封装

<?php


namespace RabbitMQ;

use PhpAmqpLib\Connection\AMQPStreamConnection;
use PhpAmqpLib\Message\AMQPMessage;

class RabbitMQ
{

    private $host = '127.0.0.1';
    private $port = 5672;
    private $user = 'guest';
    private $password = 'guest';
    protected $connection;
    protected $channel;


    /**
     * RabbitMQ constructor.
     */
    public function __construct()
    {
        $this->connection = new AMQPStreamConnection($this->host, $this->port, $this->user, $this->password);
        $this->channel    = $this->connection->channel();
    }

    /**
     * 生成信息
     * @param $message
     */
    public function sendMessage($message, $routeKey, $exchange = '', $properties = [])
    {
        $data = new AMQPMessage(
            $message, $properties
        );
        $this->channel->basic_publish($data, $exchange, $routeKey);
    }

    /**
     * 消费消息
     * @param $queueName
     * @param $callback
     * @throws \ErrorException
     */
    public function consumeMessage($queueName,$callback)
    {
        $this->channel->basic_consume($queueName, '', false, false, false, false, $callback);
        while ($this->channel->is_consuming()) {
            $this->channel->wait();
        }
    }

    /**
     * @throws \Exception
     */
    public function __destruct()
    {
        $this->channel->close();
        $this->connection->close();
    }
}

创建延时队列

<?php


namespace RabbitMQ;

use PhpAmqpLib\Exchange\AMQPExchangeType;
use PhpAmqpLib\Message\AMQPMessage;
use PhpAmqpLib\Wire\AMQPTable;

/**
 * 使用RabbitMQ实现延时队列功能
 * Class DelayQueue
 * @package RabbitMQ
 */
class DelayQueue extends RabbitMQ
{

    /**
     * 创建延时队列
     * @param $ttl
     * @param $delayExName
     * @param $delayQueueName
     * @param $queueName
     */
    public function createQueue($ttl, $delayExName, $delayQueueName, $queueName)
    {
        $args = new AMQPTable([
            'x-dead-letter-exchange'    => $delayExName,
            'x-message-ttl'             => $ttl, //消息存活时间
            'x-dead-letter-routing-key' => $queueName
        ]);
        $this->channel->queue_declare($queueName, false, true, false, false, false, $args);
        //绑定死信queue
        $this->channel->exchange_declare($delayExName, AMQPExchangeType::DIRECT, false, true, false);
        $this->channel->queue_declare($delayQueueName, false, true, false, false);
        $this->channel->queue_bind($delayQueueName, $delayExName, $queueName, false);
    }
}

生产者，代码很简单，看看运行之后的效果，订单的message越来越多

<?php
require_once '../vendor/autoload.php';

// 生产者

$delay = new \RabbitMQ\DelayQueue();

$ttl            = 1000 * 100;//订单100s后超时
$delayExName    = 'delay-order-exchange';//超时exchange
$delayQueueName = 'delay-order-queue';//超时queue
$queueName      = 'ttl-order-queue';//订单queue

$delay->createQueue($ttl, $delayExName, $delayQueueName, $queueName);

//100个订单信息，每个订单超时时间都是10s
for ($i = 0; $i < 100; $i++) {
    $data = [
        'order_id' => $i + 1,
        'remark'   => 'this is a order test'
    ];
    $delay->sendMessage(json_encode($data), $queueName);
    sleep(1);
}

消费者，看看消费之后的，过一会会观察到，已经有到期message被push到了delay_order_queue

消费者也消费到了message

<?php
require_once '../vendor/autoload.php';

// 消费者

$delay = new \RabbitMQ\DelayQueue();

$delayQueueName = 'delay-order-queue';

$callback = function ($msg) {
    echo $msg->body . PHP_EOL;
    $msg->delivery_info['channel']->basic_ack($msg->delivery_info['delivery_tag']);

    //处理订单超时逻辑，给用户推送提醒等等。。。
    sleep(10);
};

/**
 * 消费已经超时的订单信息，进行处理
 */
$delay->consumeMessage($delayQueueName, $callback);

代码见：https://github.com/jiaoyang3/...