Manual Graceful Shutdown PHP Shared Memory

GracefulShutdown.php

<?php

declare(strict_types=1);

use SysvSharedMemory;

class GracefulShutdown
{
    public const KEY = 666;

    public const SIGTERM = 'SIGTERM';

    public function signalReceived(): bool
    {
        if (! shm_has_var($this->identifier(), self::KEY)) {
            $this->clearSignal();
        }
        return shm_get_var($this->identifier(), self::KEY) === self::SIGTERM;
    }

    public function sendSignal(string $signal): void
    {
        shm_put_var($this->identifier(), self::KEY, $signal);
    }

    public function clearSignal(): void
    {
        $this->sendSignal('');
    }

    private function identifier(): SysvSharedMemory|false
    {
        return shm_attach(self::KEY, 1024, 0777);
    }
}