Magento – rabbitmq queue – order, turn on/off

Integration with Rabbitmq is EE only functionality.

But you can use it in CE version if use external library and develop infrastructure by self.

Also, you can create separate group for cron task and write code in style like

$startTime = microtime();
while( microtime(1) - $startTume > 60 * 1000) {
   // process messages
   usleep(100);
}

Here is the way that I have fulfilled the requirement to send the order details automatically to Queue once the order is placed.

<?php

namespace Test\Module\Observer;
use Magento\Framework\Event\ObserverInterface;
use Magento\Framework\MessageQueue\PublisherInterface;
use Test\Module\Api\MessageInterface;

class Pushqueue implements ObserverInterface
{
    public $orderFacory;
    public $publisher;
    public $message;

    public function __construct(
        \Magento\Sales\Model\Order $orderFacory,
        PublisherInterface $publisher,
        MessageInterface $message,
        $name = null

    ) {
        $this->orderFacory = $orderFacory; 
        $this->publisher = $publisher;
        $this->message = $message;       
        //parent::__construct($name);
    }

    public function execute(\Magento\Framework\Event\Observer $observer)
    {
        $topic = 'sender';
        $orderIds = $observer->getEvent()->getOrderIds();
         $lastorderId = $orderIds[0];
        try {
            $order = $this->orderFacory->load($lastorderId);

            foreach($order->getAllVisibleItems() as $item){
                $itemsData = array();
                $orderData[]= $item->getData();
                /*$orderData[$itemsData['price']]= $item->getPrice();
                $orderData[$itemsData['quoteItem_id']]= $item->getQuoteItemId();
                $orderData[$itemsData['item_id']]= $item->getItemId();*/
            }
            $orderData[] = $order->getData();


            $this->message->setMessage($orderData);
            $this->publisher->publish($topic, $this->message);

        return $this;

        } catch (Exception $e) {
            print_r($e->getMessage());
        }

    }


}

This observer is getting called with event

<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:Event/etc/events.xsd">
<event name="checkout_onepage_controller_success_action">
    <observer name="test_module" instance="Test\Module\Observer\Pushqueue"  />
</event>
</config>

my communication.xml

<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework-message-queue:etc/queue.xsd">
<topic name="sender" request="Test\Module\Api\MessageInterface" />
<topic name="sender2" request="Test\Module\Api\MessageInterface" />
</config>

These are the main files and this link will help you further https://inviqa.com/blog/magento-2-tutorial-message-queues. Please let me know if you need any more details. I would love to help to the one who helps all.. :)