rabbitmq延时队列

场景一：物联网系统经常会遇到向终端下发命令，如果命令一段时间没有应答，就需要设置成超时。

场景二：订单下单之后30分钟后，如果用户没有付钱，则系统自动取消订单。

最近的一个项目遇到了这种情况，如果运单30分钟还没有被接单，则状态自动变为已取消。实现延迟消息原理如下，借用一张图：

 

实现方案

1. 定时任务轮询数据库，看是否有产生新任务，如果产生则消费任务

2. pcntl_alarm为进程设置一个闹钟信号

3. swoole的异步高精度定时器:swoole_time_tick(类似javascript的setInterval)和swoole_time_after(相当于javascript的setTimeout)

4. rabbitmq延迟任务

以上四种方案,如果生产环境有使用到swoole建议使用第三种方案。此篇文章重点讲述第四种方案实现

 

 

 

<?php
require_once __DIR__ . '/../vendor/autoload.php';
use PhpAmqpLib\Connection\AMQPStreamConnection;
use PhpAmqpLib\Message\AMQPMessage;


$queue = "test_ack_queue";
$exchange = "test_ack_queue";
//获取连接
$connection = new AMQPStreamConnection('localhost', 5672, 'guest', 'guest');
//从连接中创建通道
$channel = $connection->channel();

$channel->exchange_declare('delay_exchange', 'direct',false,true,false);
$channel->exchange_declare('cache_exchange', 'direct',false,true,false);

$tale = new \PhpAmqpLib\Wire\AMQPTable();
$tale->set('x-dead-letter-exchange', 'delay_exchange');
$tale->set('x-dead-letter-routing-key','delay_exchange');
//$tale->set('x-message-ttl',10000);

$channel->queue_declare('cache_queue',false,true,false,false,false,$tale);
$channel->queue_bind('cache_queue', 'cache_exchange','cache_exchange');

$channel->queue_declare('delay_queue',false,true,false,false,false);
$channel->queue_bind('delay_queue', 'delay_exchange','delay_exchange');


$msg = new AMQPMessage('Hello World',array(
    'expiration' => 10000,
    'delivery_mode' => AMQPMessage::DELIVERY_MODE_PERSISTENT

));

$channel->basic_publish($msg,'cache_exchange','cache_exchange');
echo date('Y-m-d H:i:s')." [x] Sent 'Hello World!' ".PHP_EOL;




//while ($wait) {
//    $channel->wait();
//}

$channel->close();
$connection->close();

 

 

<?php
require_once __DIR__ . '/../vendor/autoload.php';
use PhpAmqpLib\Connection\AMQPStreamConnection;
use PhpAmqpLib\Message\AMQPMessage;


//获取连接
$connection = new AMQPStreamConnection('localhost', 5672, 'guest', 'guest');
//从连接中创建通道
$channel = $connection->channel();


//$channel->queue_declare($queue, false, true, false, false);
//$channel->exchange_declare($exchange, 'topic', false, true, false);
//$channel->queue_bind($queue, $exchange);



$channel->exchange_declare('delay_exchange', 'direct',false,false,false);
$channel->queue_declare('delay_queue',false,true,false,false,false);
$channel->queue_bind('delay_queue', 'delay_exchange','delay_exchange');



function process_message(AMQPMessage $message)
{
    $headers = $message->get('application_headers');
    $nativeData = $headers->getNativeData();
//    var_dump($nativeData['x-delay']);
    echo date('Y-m-d H:i:s')." [x] Received",$message->body,PHP_EOL;
    $message->delivery_info['channel']->basic_ack($message->delivery_info['delivery_tag']);

}


$channel->basic_qos(null, 1, null);
$channel->basic_consume('delay_queue', '', false, false, false, false, 'process_message');

function shutdown($channel, $connection)
{
    $channel->close();
    $connection->close();
}
register_shutdown_function('shutdown', $channel, $connection);

while (count($channel->callbacks)) {
    $channel->wait();
}