Cachet/app/Segment/CacheRepository.php

<?php

namespace CachetHQ\Cachet\Segment;

use CachetHQ\Cachet\Facades\Setting;
use CachetHQ\Cachet\Models\Setting as SettingModel;
use Carbon\Carbon;
use Illuminate\Database\QueryException;

class CacheRepository implements RepositoryInterface
{
    /**
     * @var \CachetHQ\Cachet\Segment\RepositoryInterface
     */
    protected $repository;

    /**
     * Instantiates a new instance of the Cache Repository.
     *
     * @param \CachetHQ\Cachet\Segment\RepositoryInterface $repository
     */
    public function __construct(RepositoryInterface $repository)
    {
        $this->repository = $repository;
    }

    /**
     * Determines whether to use the segment_write_key setting or to fetch a new.
     *
     * @return string
     */
    public function fetch()
    {
        $writeKey = null;

        // We might not be setup yet.
        try {
            // Firstly, does the setting exist?
            if (false === ($writeKey = Setting::get('segment_write_key'))) {
                // No, let's go fetch it.
                $writeKey = $this->repository->fetch();
                Setting::set('segment_write_key', $writeKey);
            } else {
                // It does, but how old is it?
                $setting = SettingModel::where('name', 'segment_write_key')->first();

                // It's older than an hour, let's refresh
                if ($setting->updated_at->lt(Carbon::now()->subHour())) {
                    $writeKey = $this->repository->fetch();

                    // Update the setting. This is done manual to make sure updated_at is overwritten.
                    $setting->value = $writeKey;
                    $setting->updated_at = Carbon::now();
                    $setting->save();
                }
            }
        } catch (QueryException $e) {
            // Just return it until we're setup.
            $writeKey = $this->repository->fetch();
        }

        return $writeKey;
    }
}