我正在使用带有 Symfony 4 Messenger 组件的 worker。

这个 worker 是

• 接收消息(来自rabbitMQ)
• 启动ffmpeg
• 对视频进行处理
• 并在数据库中保存一些东西。

为了在 Symfony 上配置这个 worker，我已经这样做了(中间件很重要):

// config/packages/framework.yaml
framework:
    messenger:
        buses:
            command_bus:
                middleware:
                    # each time a message is handled, the Doctrine connection
                    # is "pinged" and reconnected if it's closed. Useful
                    # if your workers run for a long time and the database
                    # connection is sometimes lost
                    - doctrine_ping_connection

                    # After handling, the Doctrine connection is closed,
                    # which can free up database connections in a worker,
                    # instead of keeping them open forever
                    - doctrine_close_connection

        transports:
            ffmpeg:
              dsn: '%env(CLOUDAMQP_URL)%'
              options:
                auto_setup: false
                exchange:
                    name: amq.topic
                    type: topic
                queues:
                  ffmpeg: ~

        routing:
            # Route your messages to the transports, for now all are AMQP messages
            'App\Api\Message\AMQPvideoFFMPEG': ffmpeg
        ## Handle multiple buses ? https://symfony.com/doc/current/messenger/multiple_buses.html
        ## When queries and command should be distinguished

然后为了了解可能导致此问题的原因，我尝试调试 Messenger 以查看中间件是否已正确配置

root@b9eec429cb54:/var/www/html# php bin/console debug:messenger

Messenger
=========

command_bus
-----------

 The following messages can be dispatched:

 ------------------------------------------------------ 
  App\Api\Message\AMQPvideoFFMPEG                       
      handled by App\Api\Message\Handler\FFMPEGHandler  
 ------------------------------------------------------ 

一切似乎都还好吧？

那怎么可能看到这个:

[2019-08-23 10:25:26] messenger.ERROR: Retrying App\Api\Message\AMQPvideoFFMPEG - retry #1. {"message":"[object] (App\Api\Message\AMQPvideoFFMPEG: {})","class":"App\Api\Message\AMQPvideoFFMPEG","retryCount":1,"error":"[object] (Doctrine\DBAL\Exception\ConnectionException(code: 0): An exception occurred in driver: SQLSTATE[HY000] [2002] Connection timed out at /var/www/html/vendor/doctrine/dbal/lib/Doctrine/DBAL/Driver/AbstractMySQLDriver.php:93, Doctrine\DBAL\Driver\PDOException(code: 2002): SQLSTATE[HY000] [2002] Connection timed out at /var/www/html/vendor/doctrine/dbal/lib/Doctrine/DBAL/Driver/PDOConnection.php:31, PDOException(code: 2002): SQLSTATE[HY000] [2002] Connection timed out at /var/www/html/vendor/doctrine/dbal/lib/Doctrine/DBAL/Driver/PDOConnection.php:27)"} []

我完全迷路了，我错过了什么吗？

这有时会发生，但大部分时间都有效，我想这个错误发生在我的工作人员失去与数据库的连接时，特别是如果 ffmpeg 处理持续 7 分钟或更长时间，但这应该通过 ping 和关闭来避免连接的中间件。所以我不清楚这里的问题是什么。

最佳答案

在阅读了我的中间件代码，尤其是这个 block 之后

https://github.com/symfony/symfony/blob/4.4/src/Symfony/Bridge/Doctrine/Messenger/DoctrinePingConnectionMiddleware.php

class DoctrinePingConnectionMiddleware extends AbstractDoctrineMiddleware
{
    protected function handleForManager(EntityManagerInterface $entityManager, Envelope $envelope, StackInterface $stack): Envelope
    {
        $connection = $entityManager->getConnection();
        if (!$connection->ping()) {
            $connection->close();
            $connection->connect();
        }
        if (!$entityManager->isOpen()) {
            $this->managerRegistry->resetManager($this->entityManagerName);
        }
        return $stack->next()->handle($envelope, $stack);
    }
}

我们可以看到我的处理程序在连接打开后立即被调用。 这种行为应该有效，我认为它是，但 FFMPEG 可以在很长一段时间内使用相同的 RabbitMQ 消息工作。因此，我的处理程序将某些内容插入数据库的最后一步可能会提供 mySQL 已消失错误或连接超时。

这就是为什么，我将这个片段放入一个方法中，而不调用处理程序，只调用与学说连接相关的代码，然后我在插入我的数据库之前调用它，如下所示:

public function __invoke(AMQPvideoFFMPEG $message)
    {
        // reset connection if not found
        $this->processService->testConnection();
        $process = $this->processService->find($message->getProcess());
        $this->renderServcie->updateQueue($process->getQueue(), "processing");

// some other stuff
}

testConnection()方法在哪里

 /**
     * Reconnect if connection is aborted for some reason
     */
    public function testConnection()
    {
        $connection = $this->entityManager->getConnection();
        if (!$connection->ping()) {
            $connection->close();
            $connection->connect();
        }

    }

但在那之后我又尝试了另一个问题

Resetting a non-lazy manager service is not supported. Set the "doctrine.orm.default_entity_manager" service as lazy and require "symfony/proxy-manager-bridge" in your composer.json file instead.

安装“symfony/proxy-manager-bridge”后，错误消失了。

到目前为止，还没有遇到连接超时的情况。拭目以待。

关于php - 使用学说的 Symfony 4 工作人员无法正常工作 : SQLSTATE[HY000] [2002] Connection timed out，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/57627270/