There are too many options to configure your Growl Application, and we will not see it all, but just few of them.

In following example, our goal is to see how to change easily, look and feel of your application, displayed by your Growl client.

We will :

We will also filter messages, with help of CallbackFilterHandler ^[2]

Filter rules. 

<?php
$filters = array(
    function ($record) {
        if ($record['level'] < Logger::WARNING) {
            return true;
        }
        if (!array_key_exists('exception', $record['context'])) {
            return false;
        }
        return (preg_match('/^An error has occured/', $record['message']) === 1);
    }
);

To change notification’s icons, we have to :

To change application icon, that identified it in your Growl client :

<?php

    $options = array(
        'AppIcon' => $resourceDir . 'growl-starkicon.png',
    );

Have a look on the PEAR Net_Growl documentation, to learn more about all features, and options.

Now your full script should be like this one :

<?php
require_once 'vendor/autoload.php';

use Bartlett\Monolog\Handler\GrowlHandler;
use Bartlett\Monolog\Handler\CallbackFilterHandler;

use Monolog\Logger;
use Monolog\Handler\RotatingFileHandler;
use Monolog\Formatter\LineFormatter;

// Create the logger
$logger = new Logger('growl_conf');

// Create filter rules
$filters = array(
    function ($record) {
        if ($record['level'] < Logger::WARNING) {
            return true;
        }
        if (!array_key_exists('exception', $record['context'])) {
            return false;
        }
        return (preg_match('/^An error has occured/', $record['message']) === 1);
    }
);

// Create some handlers
$stream = new RotatingFileHandler(__DIR__ . DIRECTORY_SEPARATOR . 'growl_conf.log');
$stream->setFilenameFormat('{filename}-{date}', 'Ymd');

$logger->pushHandler($stream);

try {
    $resourceDir   = __DIR__ . DIRECTORY_SEPARATOR . 'images' . DIRECTORY_SEPARATOR;
    $notifications = array(
        GrowlHandler::DEBUG => array(
            'icon'    => $resourceDir . 'green.png',
        ),
        GrowlHandler::INFO => array(
            'icon'    => $resourceDir . 'green.png',
        ),
        GrowlHandler::NOTICE => array(
            'icon'    => $resourceDir . 'yellow.png',
        ),
        GrowlHandler::WARNING => array(
            'icon'    => $resourceDir . 'yellow.png',
        ),
        GrowlHandler::ERROR => array(
            'icon'    => $resourceDir . 'red.png',
        ),
        GrowlHandler::CRITICAL => array(
            'icon'    => $resourceDir . 'red.png',
        ),
        GrowlHandler::ALERT => array(
            'icon'    => $resourceDir . 'red.png',
        ),
        GrowlHandler::EMERGENCY => array(
            'icon'    => $resourceDir . 'red.png',
        ),
    );
    $options = array(
        'AppIcon' => $resourceDir . 'growl-starkicon.png',
        // if you have troubles with Net_Growl then debug requests to a local file
        //'debug'   => __DIR__ . '/net_growl_debug.log',
    );

    $growl = new GrowlHandler(
        array(
            'name'          => 'My Custom Growl',
            'notifications' => $notifications,
            'options'       => $options,
        )
    );
    $growl->setFormatter(
        new LineFormatter("%message%\n%level_name%")
    );

    $logger->pushHandler(new CallbackFilterHandler($growl, $filters));

} catch (\Exception $e) {
    // Growl server is probably not started
    echo $e->getMessage(), PHP_EOL, PHP_EOL;
}

// You can now use your logger
$logger->addInfo('My logger is now ready');

// This record won't be stopped by the $filters rules, but by the growl $notifications config
$logger->addDebug('A debug message.');

$logger->addError('An error has occured. Will be logged to file BUT NOT notified by Growl.');

try {
    throw new \RuntimeException();

} catch (\Exception $e) {
    $logger->addCritical(
        'An error has occured. Will be logged to file AND notified by Growl.',
        array('exception' => $e)
    );
}

Monolog uses only the eight RFC 5424 levels (debug, info, notice, warning, error, critical, alert, emergency) for basic filtering purposes.

If it’s enough to limit log records received by each handler, we need more flexibility with GrowlHandler to avoid to be spammed with ton of log records.

We have a start of solution with the FilterHandler available in Monolog since version 1.8.0, that filter log records on one or more levels. But this is not without counted the new CallbackFilterHandler that raised this limitation, and allow advanced filtering behaviours (you can filter on each log record property).

Suppose you want to be notified at end of a long process with a specific message or contextual data, CallbackFilterHandler is what you’re waiting for.

It can be combined as a wrapper with any other monolog handlers, and not just the GrowlHandler.

Here we will only demonstrate its capabilities in one example. We simulate a file queue processing that log all filenames and a message when it’s over.

<?php
require_once 'vendor/autoload.php';

use Monolog\Logger;
use Monolog\Handler\RotatingFileHandler;
use Monolog\Processor\PsrLogMessageProcessor;

$processors = array(
    new PsrLogMessageProcessor(),
);

// Create the logger
$logger = new Logger('long_process', array(), $processors);

// Create some handlers
$stream = new RotatingFileHandler(__DIR__ . DIRECTORY_SEPARATOR . 'long_process.log');
$stream->setFilenameFormat('{filename}-{date}', 'Ymd');

$logger->pushHandler($stream);

// Processing each file in a queue
$queue = new \SplQueue();
for ($i = 1; $i < 10; $i++) {
    $queue->enqueue( sprintf('File_%02d.txt', $i) );
}
$fileCount = count($queue);

while (!$queue->isEmpty()) {
    $file = $queue->dequeue();

    $logger->addInfo('Processing file "{filename}"', array('filename' => $file));
    echo '.';

    // simulate the long process
    sleep(1);
}

$logger->addInfo(
    'Long Process with {count} files, is over !',
    array('count' => $fileCount)
);

At this step, if we just push an instance of GrowlHandler to the logger stack, as following

<?php
use Bartlett\Monolog\Handler\GrowlHandler;

try {
    $growl = new GrowlHandler(
        array(), // with all default options
        Logger::INFO
    );

    $logger->pushHandler($growl);

} catch (\Exception $e) {
    // Growl server is probably not started
    echo $e->getMessage(), PHP_EOL;
}

We will receive all log INFO record notifications to our Growl client.

The solution is to use the CallbackFilterHandler to send only one notification (the end message only).

Suppose we want to be notified only if at least 5 files were proceeded.

Filter rules. 

<?php

    $filters = array(
        function ($record) {
            if (!array_key_exists('count', $record['context'])) {
                return false;
            }
            return ($record['context']['count'] > 5);
        }
    );

And in script, we will replaced the previous $growl instance with this one :

<?php
use Bartlett\Monolog\Handler\CallbackFilterHandler;

    $growl = new CallbackFilterHandler(
        new GrowlHandler(
            array(), // with all default options
            Logger::INFO
        ),
        $filters
    );

	Filter rules limitation is only your imagination !