Add message to queue

Overview

WARNING

Parts of this guide refer to the low_priority queue and the corresponding LowPriorityMessageInterface, which is only available in version 6.5.7.0 and above. Configuring the messenger to consume this queue will fail if it does not exist.

In this guide you'll learn how to create a message and add it to the queue.

Shopware integrates with the Symfony Messenger component and Enqueue. This gives you the possibility to send and handle asynchronous messages.

A message is a simple PHP object that you want to dispatch over the MessageQueue. It must be serializable and should contain all necessary information that your handlers need to process the message.

It will be wrapped in an envelope by the message bus that dispatches the message.

Prerequisites

As most guides, this guide is also built upon the Plugin base guide, but you don't necessarily need that. It will use an example service, so if you don't know how to add a custom service yet, have a look at our guide about Adding a custom service. Furthermore, registering classes or services to the DI container is also not explained here, but it's covered in our guide about Dependency injection, so having this open in another tab won't hurt.

Create a message

First, we have to create a new message class in the directory <plugin root>/MessageQueue/Message. In this example, we create a SmsNotification that contains a string with content. By default, all messages are handled synchronously. To change the behavior to asynchronously, we have to implement the AsyncMessageInterface interface. For messages which should also be handled asynchronously but with a lower priority, implement the LowPriorityMessageInterface interface.

Here's an example:

// <plugin root>/src/MessageQueue/Message/SmsNotification.php
<?php declare(strict_types=1);

namespace Swag\BasicExample\MessageQueue\Message;

use Shopware\Core\Framework\MessageQueue\AsyncMessageInterface;

class SmsNotification implements AsyncMessageInterface
{
    private string $content;

    public function __construct(string $content)
    {
        $this->content = $content;
    }

    public function getContent(): string
    {
        return $this->content;
    }
}

Send a message

After we've created our notification, we will create a service that will send our SmsNotification. We will name this service ExampleSender. In this service we need to inject the Symfony\Component\Messenger\MessageBusInterface, that is needed to send the message through the desired bus, which is called messenger.bus.shopware.

// <plugin root>/src/Service/ExampleSender.php
<?php declare(strict_types=1);

namespace Swag\BasicExample\Service;

use Swag\BasicExample\MessageQueue\Message\SmsNotification;
use Symfony\Component\Messenger\MessageBusInterface;

class ExampleSender
{
    private MessageBusInterface $bus;

    public function __construct(MessageBusInterface $bus)
    {
        $this->bus = $bus;
    }

    public function sendMessage(string $message): void
    {
        $this->bus->dispatch(new SmsNotification($message));
    }
}

If we want to add metadata to our message, we can dispatch an Symfony\Component\Messenger\Envelope in our service instead with the necessary stamps. In this example below, we use the Symfony\Component\Messenger\Stamp\DelayStamp, which tells the queue to process the message later.

// <plugin root>/src/Service/ExampleSender.php
public function sendMessage(string $message): void
{
    $message = new SmsNotification($message);
    $this->bus->dispatch(
        (new Envelope($message))
            ->with(new DelayStamp(5000))
    );
}

Lower the priority for specific async messages

You might consider using the new low_priority queue if you are dispatching messages that do not need to be handled immediately. To configure specific messages to be transported via the low_priority queue, you need to either adjust the routing or implement the LowPriorityMessageInterface as already mentioned:

# config/packages/shopware.yaml
shopware:
    messenger:
        routing_overwrite:
            'Your\Custom\Message': low_priority

Override transport for specific messages

If you explicitly configure a message to be transported via the async (default) queue, even though it implements the LowPriorityMessageInterface, which would usually be transported via the low_priority queue, the transport is overridden for this specific message.

Example:

// <plugin root>/src/MessageQueue/Message/LowPriorityMessage.php
<?php declare(strict_types=1);

namespace Your\Custom;

use Shopware\Core\Framework\MessageQueue\LowPriorityMessageInterface;

class LowPriorityMessage implements LowPriorityMessageInterface
{
}

# config/packages/shopware.yaml
shopware:
    messenger:
        routing_overwrite:
            'Shopware\Core\Framework\MessageQueue\LowPriorityMessageInterface': low_priority
            'Your\Custom\LowPriorityMessage': async

Next steps

Now that you know how to create a message and add it to the queue, let's create a handler to process our message. To do this, head over to Add message handler guide.