BookStack/app/Config/logging.php

<?php

use Monolog\Handler\NullHandler;
use Monolog\Handler\StreamHandler;

/**
 * Logging configuration options.
 *
 * Changes to these config files are not supported by BookStack and may break upon updates.
 * Configuration should be altered via the `.env` file or environment variables.
 * Do not edit this file unless you're happy to maintain any changes yourself.
 */

return [

    // Default Log Channel
    // This option defines the default log channel that gets used when writing
    // messages to the logs. The name specified in this option should match
    // one of the channels defined in the "channels" configuration array.
    'default' => env('LOG_CHANNEL', 'single'),

    // Log Channels
    // Here you may configure the log channels for your application. Out of
    // the box, Laravel uses the Monolog PHP logging library. This gives
    // you a variety of powerful log handlers / formatters to utilize.
    // Available Drivers: "single", "daily", "slack", "syslog",
    //                    "errorlog", "monolog",
    //                    "custom", "stack"
    'channels' => [
        'stack' => [
            'driver' => 'stack',
            'channels' => ['daily'],
            'ignore_exceptions' => false,
        ],

        'single' => [
            'driver' => 'single',
            'path' => storage_path('logs/laravel.log'),
            'level' => 'debug',
            'days' => 14,
        ],

        'daily' => [
            'driver' => 'daily',
            'path' => storage_path('logs/laravel.log'),
            'level' => 'debug',
            'days' => 7,
        ],

        'slack' => [
            'driver' => 'slack',
            'url' => env('LOG_SLACK_WEBHOOK_URL'),
            'username' => 'Laravel Log',
            'emoji' => ':boom:',
            'level' => 'critical',
        ],

        'stderr' => [
            'driver' => 'monolog',
            'handler' => StreamHandler::class,
            'with' => [
                'stream' => 'php://stderr',
            ],
        ],

        'syslog' => [
            'driver' => 'syslog',
            'level' => 'debug',
        ],

        'errorlog' => [
            'driver' => 'errorlog',
            'level' => 'debug',
        ],

        'null' => [
            'driver' => 'monolog',
            'handler' => NullHandler::class,
        ],
    ],

];