Allow to know if the logger has handlers which handle a level

[egeloen]

Hi,

I'm currently integrating Monolog in a project which needs to know if the logger has handlers for a specific level. In this case, my app will create some specific objects in order to debug more precisely what's happened.

Currently, I must override the logger for being able to acces handlers.

If you're OK with this feature, I will create a PR.

[stof]

there is an issue here: an handler decides to handle a specific message. All built-in handlers use only the level for this but you could imagine other behaviors for a custom handler: handling the message only for a specific channel, or only when some key exist in the context, or even randomly if you see a reason to do so.

[egeloen]

Yes but my interest here is to know if there is at least one handler which is able to handle my message according to the level. I will give an example:

<?php

if ($logger->hasHandlers(Logger::DEBUG) {
    $logger->addDebug('my_message');
}

With that, before adding a debug message, I'm able to detect if there is indeed an handler which will be able to handle my message.

[stof]

well, you can add the debug message. Monolog already checks internally if the message is handled by an handler (and supporting any check done in the handler) and returns early otherwise.

[egeloen]

Sorry but I will try to explain me better.

What I want to do is to instanciate an object which will debug the execution time of some queries if there is an handler which is able to handle the level I use.

So, I would like my code looks like:

<?php

$debugStack = new DebugStack();

if ($logger->hasHandlers(Logger::INFO)) {
    $debugStack->start();
}

// Execute queries

if ($logger->hasHandlers(Logger::INFO)) {
    $debugStack->stop();
    $logger->addInfo($debugStack->toString());
}

I hope you understand my interest to detect if the logger can handle my message :)

[Seldaek]

I guess a better implementation would be to use something similar to the existing isHandling:

    public function isHandling($level) 
    {
        $record = array(
            'message' => '',
            'context' => array(),
            'level' => $level,
            'level_name' => self::getLevelName($level),
            'channel' => $this->name,
            'datetime' => new \DateTime(),
            'extra' => array(),
        );
        foreach ($this->handlers as $key => $handler) {
            if ($handler->isHandling($record)) {
                return true;
            }
        }

        return false;
    }

It's not so efficient though to create a dummy log record and loop through handlers.

[egeloen]

That's exactly what I want :)

Are you agree to add this feature to the core?

[Seldaek]

Done

[egeloen]

Thanks !