RabbitMq初探——消息均发
消息均发
前言
由前文 RabbitMq初探——消息分发 可知,rabbitmq自带分发机制——消息会按顺序的投放到该队列下的多个消费者,例如1,3,5投放消费者C1,2,4,6投放消费者C2。
这就有个隐含的缺点:每个消息的消费时间可能不一样,极端情况下,投放给C1的每个消息消费都需要很长时间,而投放给C2的每个消息消费需要很短,就会导致C1进程
负担重,C2进程很悠闲。
所以,我们需要根据任务量来均发消息。
均发消息实现
1. 开启消息确认机制。
2. 为每个消费者分配且只分配一个消息,待rabbitmq收到消费者的ack后再发送后面的消息。通过这种手段,耗时很短的消息消费掉,发送ack,rabbitmq收到确认,分配下一个
消息给该消费者。不会存在很悠闲的消费者进程。
php代码实现
需要在消费者代码中加入 预定消息数量=1 的代码
$channel->basic_qos(null, 1, null);
整体代码如下:
sender.php
<?php /** * sender.php * Created by PhpStorm. * User: wangdaxi * Date: 2017/10/18 * Time: 14:26 */ require_once __DIR__ . '/vendor/autoload.php'; use PhpAmqpLib\Connection\AMQPStreamConnection; use PhpAmqpLib\Message\AMQPMessage; $connection = new AMQPStreamConnection('127.0.0.1', 5672, 'guest', 'guest'); $channel = $connection->channel(); $channel->queue_declare('durable_queue', false, true, false, false); $data = implode(" ", array_slice($argv, 1)); empty($data) && $data = "Hello World!"; $msg = new AMQPMessage($data, array('delivery_mode' => AMQPMessage::DELIVERY_MODE_PERSISTENT)); $channel->basic_publish($msg, '', 'durable_queue'); echo " [x] Sent '$data'\n"; //close the channel and connection; $channel->close(); $connection->close();
receive.php
<?php /** * receive.php * Created by PhpStorm. * User: wangdaxi * Date: 2017/10/18 * Time: 14:34 */ require_once __DIR__ . '/vendor/autoload.php'; use PhpAmqpLib\Connection\AMQPStreamConnection; $connection = new AMQPStreamConnection('127.0.0.1', 5672, 'guest', 'guest'); $channel = $connection->channel(); $channel->queue_declare('durable_queue', false, true, false, false); $channel->basic_qos(null, 1, null); echo ' [*] Waiting for messages. To exit press CTRL+C', "\n"; $callback = function($msg) { echo "[x] Received ", $msg->body, "\n"; sleep(substr_count($msg->body, '.')); echo "[x] Done\n"; //消息确认 $msg->delivery_info['channel']->basic_ack($msg->delivery_info['delivery_tag']); }; $channel->basic_consume('durable_queue', '', false, false, false, false, $callback); while(count($channel->callbacks)) { $channel->wait(); }
验证
开启两个终端作为消费者C1,C2。
开启一个终端作为生产者P。
P持续生产任务量不一样的消息(用.的个数表示任务量大小)
看C1处理消息
看C2处理消息
以上。