Errors & Logging

• Introduction
• Configuration
• The Exception Handler
  • Report Method
  • Render Method
• HTTP Exceptions
• Logging

Introduction

When you start a new Lumen project, error and exception handling is already configured for you. In addition, Lumen is integrated with the Monolog logging library, which provides support for a variety of powerful log handlers.

Configuration

Error Detail

The amount of error detail your application displays through the browser is controlled by the APP_DEBUG configuration option in your .env file.

For local development, you should set the APP_DEBUG environment variable to true. In your production environment, this value should always be false.

Custom Monolog Configuration

If you would like to have complete control over how Monolog is configured for your application, you may use the application's configureMonologUsing method. You should place a call to this method in your bootstrap/app.php file:

$app->configureMonologUsing(function($monolog) {
    $monolog->pushHandler(...);
    return $monolog;
});
return $app;

The Exception Handler

All exceptions are handled by the App\Exceptions\Handler class. This class contains two methods: report and render. We'll examine each of these methods in detail.

The Report Method

The report method is used to log exceptions or send them to an external service like BugSnag. By default, the report method simply passes the exception to the base class where the exception is logged. However, you are free to log exceptions however you wish.

For example, if you need to report different types of exceptions in different ways, you may use the PHP instanceof comparison operator:

/**
 * Report or log an exception.
 *
 * This is a great spot to send exceptions to Sentry, Bugsnag, etc.
 *
 * @param  \Exception  $e
 * @return void
 */
public function report(Exception $e)
{
    if ($e instanceof CustomException) {
        //
    }
    return parent::report($e);
}

Ignoring Exceptions By Type

The $dontReport property of the exception handler contains an array of exception types that will not be logged. By default, exceptions resulting from 404 errors are not written to your log files. You may add other exception types to this array as needed.

The Render Method

The render method is responsible for converting a given exception into an HTTP response that should be sent back to the browser. By default, the exception is passed to the base class which generates a response for you. However, you are free to check the exception type or return your own custom response:

/**
 * Render an exception into an HTTP response.
 *
 * @param  \Illuminate\Http\Request  $request
 * @param  \Exception  $e
 * @return \Illuminate\Http\Response
 */
public function render($request, Exception $e)
{
    if ($e instanceof CustomException) {
        return response('Custom Message');
    }
    return parent::render($request, $e);
}

HTTP Exceptions

Some exceptions describe HTTP error codes from the server. For example, this may be a "page not found" error (404), an "unauthorized error" (401) or even a developer generated 500 error. In order to generate such a response from anywhere in your application, use the following:

abort(404);

The abort method will immediately raise an exception which will be rendered by the exception handler. Optionally, you may provide the response text:

abort(403, 'Unauthorized action.');

This method may be used at any time during the request's lifecycle.

Logging

The Lumen logging facilities provide a simple layer on top of the powerful Monolog library. By default, Lumen is configured to create a single log file for your application which is stored in the storage/logs directory. You may write information to the logs using the Log facade:

<?php
namespace App\Http\Controllers;
use Log;
use App\User;
use App\Http\Controllers\Controller;
class UserController extends Controller
{
    /**
     * Show the user for the given ID.
     *
     * @param  int  $id
     * @return Response
     */
    public function show($id)
    {
        Log::info('Showing user: '.$id);
        return User::findOrFail($id);
    }
}

Note: Before using the Log facade, be sure you have uncommented the $app->withFacades() method call in your bootstrap/app.php file.

The logger provides the eight logging levels defined in RFC 5424: emergency, alert, critical, error, warning, notice, info and debug.

Log::emergency($error);
Log::alert($error);
Log::critical($error);
Log::error($error);
Log::warning($error);
Log::notice($error);
Log::info($error);
Log::debug($error);

Contextual Information

An array of contextual data may also be passed to the log methods. This contextual data will be formatted and displayed with the log message:

Log::info('User failed to login.', ['id' => $user->id]);