queue requests with flock

flock-queue.php

public function request_queue_handler(Request $request)
    {
        header($_SERVER['SERVER_PROTOCOL'].' 200 OK');

        $amo_subdomain = $_POST['account']['subdomain'];
        $path_structure = '../'.$amo_subdomain.'/queue_files';
        $queue_file_prefix = $path_structure.'/queue_file_';
        $queue_flag_file = $path_structure.'/queue_flag';
        $lead_name = $_POST['leads']['add'][0]['name'];


        if (!file_exists($path_structure)) {
            if (!mkdir($path_structure, 0777, true)) {
                die('Failed to create folders...');
            }
        }


        file_put_contents($queue_file_prefix.microtime(true), json_encode($_POST));
        if (!file_exists($queue_flag_file)) {
            //file_put_contents($queue_flag_file, true);
            $fp = fopen($queue_flag_file, "w");
            if (flock($fp, LOCK_EX)) {  // acquire an exclusive lock
                sleep(1);
                while (!empty($files = glob($queue_file_prefix.'*'))) {
                    if (!isset($account_main_settings)) {
                        $account_main_settings = Account::where('amo_domain', $amo_subdomain)->first()->toArray();
                        $amo = Amoapi::setInstance([
                            'id'     => $account_main_settings['amo_account_id'],
                            'domain' => $account_main_settings['amo_domain'],
                            'login'  => $account_main_settings['amo_login'],
                            'hash'   => $account_main_settings['amo_api_key']
                        ]);
                        $break_point = true;
                    }
                    if (isset($amo)) {
                        foreach ($files as $file) {
                            $file_data = json_decode(file_get_contents($file), true);
                            sleep(1);
                            $lead = $amo->leads()->create((int) $file_data['leads']['add'][0]['id']);
                            $lead->name = $lead_name.'__'.microtime(true);
                            $lead->updated_at = time() + 1;
                            $leads_to_update[] = $lead;
                            $break_point = true;
                            unlink($file);
                            if (count($leads_to_update) > 499) {

                                try {
                                    $amo->leads()->update($leads_to_update);
                                    $break_point = true;
                                } catch (Exception $e) {
                                    file_put_contents($path_structure.'/exception_data.log', $e->getMessage());
                                    $break_point = true;
                                } finally {
                                    flock($fp, LOCK_UN);
                                    fclose($fp);
                                    unlink($queue_flag_file);
                                    $leads_to_update = [];
                                    file_put_contents($path_structure.'/logic_init_by_'.$lead_name, true);
                                }

                            }
                        }
                        $break_point = true;

                    }
                }
                if (isset($amo)) {
                    if (!empty($leads_to_update)) {
                        try {
                            $amo->leads()->update($leads_to_update);
                            $break_point = true;
                        } catch (Exception $e) {
                            file_put_contents($path_structure.'/exception_data.log', $e->getMessage());
                            $break_point = true;
                        } finally {
                            flock($fp, LOCK_UN);
                            fclose($fp);
                            unlink($queue_flag_file);
                            file_put_contents($path_structure.'/logic_init_by_'.$lead_name, true);
                        }

                    }
                }

            } else {
                echo "Couldn't get the lock!";
            }


        }
    }