Blossoming_Flower Blossoming_Flower - 5 months ago 16
PHP Question

Strange error: "Couldn't find constant Logger::DEBUG" when using Monolog in Laravel

I've got a simple class that allows me to write to any log file:

use Monolog\Logger;
use Monolog\Handler\StreamHandler;

class Mylog
public function __construct($log, $level = 'debug')
$this->monolog = new Logger($log);

$level = constant('Logger::'.strtoupper($level));

$this->monolog->pushHandler(new StreamHandler(storage_path('logs/'.$log.'-'.date('Y-m-d').'.txt')), $level);

public function __call($method, $arguments)

This gives me the error: constant(): Couldn't find constant Logger::DEBUG

However, when pushing the handler, if I replace $level with simply Logger::DEBUG, it works. Why is it not finding the constant when it does, in fact, exist?


The class name inside a string like in the argument to the constant() function must be fully qualified. When you do Logger::DEBUG it works because the class is use'd, so it resolves as Monolog\Logger::DEBUG but in the string it just remains Logger::DEBUG and that obviously does not exist.

Therefore the solution is simply to use the fully qualified name within strings, i.e.

$level = constant('Monolog\Logger::'.strtoupper($level));