CreateEvent.php

<?php

namespace App\Jobs;

use App\Models\Domain;
use App\Models\Event;
use Illuminate\Bus\Queueable;
use Illuminate\Contracts\Queue\ShouldQueue;
use Illuminate\Foundation\Bus\Dispatchable;
use Illuminate\Queue\InteractsWithQueue;
use Illuminate\Queue\SerializesModels;
use Illuminate\Support\Facades\Http;

class CreateEvent implements ShouldQueue
{
    use Dispatchable, InteractsWithQueue, Queueable, SerializesModels;

    const TYPE_UP = 1;
    const TYPE_DOWN = 2;

    const REASON_OK = 1;
    const REASON_FORBIDDEN_ERROR = 2;
    const REASON_CLIENT_ERROR = 3;
    const REASON_SERVER_ERROR = 4;

    /**
     * Create a new job instance.
     *
     * @return void
     */
    public function __construct()
    {
        //
    }

    /**
     * Execute the job.
     *
     * @return void
     */
    public function handle()
    {
        // should only get the columns you actually need
        $domains = Domain::select(['id', 'event_id', 'name'])->get();

        /** @var Domain $domain */
        foreach ($domains as $domain) {
            $ping = Http::get('http://'.$domain->name);

            // domain is up | checking last previous record
            // I believe getting all the events from domain relationship is unnecessary here
            // as it's querying all the events first (->get()) and then taking one record (->first())
            // Instead you can get the only row that you need here by doing the following
            $checkLatestEvent = Event::select(['id', 'domain_id', 'type'])
                ->where('domain_id', $domain->id)
                ->latest()
                ->first();

            // last record is not up, so adding a new one
            if ($ping->successful() && $checkLatestEvent->type !== self::TYPE_UP) {
                $this->recordEvent($domain, self::TYPE_UP, self::REASON_OK);
            }

            // last record is not down, so adding a new one
            if ($ping->failed() && $checkLatestEvent->type !== self::TYPE_DOWN) {
                $reason = self::REASON_FORBIDDEN_ERROR;

                if ($ping->serverError()) {
                    $reason = self::REASON_SERVER_ERROR;
                }

                if ($ping->clientError()) {
                    $reason = self::REASON_CLIENT_ERROR;
                }

                $this->recordEvent($domain, self::TYPE_DOWN, $reason);
            }
        }
    }

    private function recordEvent(Domain $domain, $latestEventType, $reason)
    {
        $domain->events()->create([
            'type' => $latestEventType,
            'reason' => $reason,
        ]);

        // todo email admin about site is up
        // I would fire an event here: DomainEvent and send the email from a listener
        // event(new DomainEvent($latestEventType, $reason))
    }
}