invoiceninja/app/Jobs/Cron/BillingSubscriptionCron.php

<?php
/**
 * Invoice Ninja (https://invoiceninja.com).
 *
 * @link https://github.com/invoiceninja/invoiceninja source repository
 *
 * @copyright Copyright (c) 2021. Invoice Ninja LLC (https://invoiceninja.com)
 *
 * @license https://opensource.org/licenses/AAL
 */

namespace App\Jobs\Cron;

use App\Libraries\MultiDB;
use App\Models\ClientSubscription;
use Illuminate\Foundation\Bus\Dispatchable;
use Illuminate\Support\Carbon;

class BillingSubscriptionCron
{
    use Dispatchable;

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

    /**
     * Execute the job.
     *
     * @return void
     */
    public function handle() : void
    {

        if (! config('ninja.db.multi_db_enabled')) {
            $this->loopSubscriptions();
        } else {
            //multiDB environment, need to
            foreach (MultiDB::$dbs as $db) {

                MultiDB::setDB($db);
                $this->loopSubscriptions();

            }
        }
    }

    private function loopSubscriptions()
    {
        $client_subs = ClientSubscription::whereNull('deleted_at')
                                           ->cursor()
                                           ->each(function ($cs){
                                                $this->processSubscription($cs);
                                            });
    }

    /* Our daily cron should check

        1. Is the subscription still in trial phase?
        2. Check the recurring invoice and its remaining_cycles to see whether we need to cancel or perform any other function.
        3. Any notifications that need to fire?
    */
    private function processSubscription($client_subscription)
    {

    }
}