* .env

LOG_CHANNEL=daily
LOG_SLACK_WEBHOOK_URL=
LOG_PATH=/storage/logs/lumen.log
LOG_MAXFILE=5

* 参照 pearl/lumen-log-rotate
 创建文件 .\app\Providers\LogRotateServiceProvider.php

<?php

namespace App\Providers;

use Monolog\Formatter\LineFormatter;
use Illuminate\Support\ServiceProvider;
use Monolog\Handler\RotatingFileHandler;

class LogRotateServiceProvider extends ServiceProvider
{

    /**
     * Perform post-registration booting of services.
     *
     * @return void
     */
    public function boot()
    {
        $handlers[] = (new RotatingFileHandler(env('LOG_PATH', storage_path('logs/lumen.log')), env('LOG_MAXFILE', 5)))
            ->setFormatter(new LineFormatter("[%datetime%] %channel%.%level_name%: %message% %context% %extra%\n", null, true, true));

        $this->app['log']->setHandlers($handlers);
    }
}
?>

* 注册服务

.\bootstrap\app.php
+1 line:

$app->register(App\Providers\LogRotateServiceProvider::class);