datadog_daemon.php

datadog_daemon.php

<?php

declare(strict_types=1);

/**
 * This script is a daemon, i.e. it will be executed by
 * systemd and kept running for a long time.
 */
class Processor
{
    public function __invoke(Message $message)
    {
        print(sprintf("processing the message %s\n", $message->id ?? 'unknown'));
        sleep(1);
    }
}

class Message
{
    /** @var string */
    public $id;

    /** @var string */
    public $body;

    public function __construct(string $id, string $body)
    {
        $this->id   = $id;
        $this->body = $body;
    }
}

function receiveMessages() : array
{
    return [
        new Message('one', 'foo'),
        new Message('two', 'bar'),
        new Message('three', 'baz'),
    ];
}

function getProcessors() : array
{
    return [
        new Processor(),
        new Processor(),
    ];
}

$processors = getProcessors();

while (true) {
    $messages = receiveMessages();

    /**
     * What I want:
     *   - each message is a resource
     *   - trace each message processor
     *   - flush traces after each consumed message
     */
    foreach ($messages as $message) {
        foreach ($processors as $processor) {
            $processor($message);
        }
    }
}