Magento Logs

Log File Locations

# Main log directory
var/log/

# Log files:
var/log/system.log      # General system events
var/log/exception.log   # Uncaught exceptions
var/log/debug.log       # Debug messages (developer mode)
var/log/payment.log     # Payment gateway logs
var/log/cron.log        # Cron job logs
var/log/setup.log       # Installation/update logs
var/log/mail.log        # Email sending logs
var/log/cron_schedule.log # Cron scheduling logs

Log Configuration

// app/etc/env.php
return [
    'log' => [
        'file' => [
            'level' => \Monolog\Logger::DEBUG,
            'path' => 'var/log/',
        ],
        'syslog' => [
            'ident' => 'magento',
            'facility' => LOG_USER,
        ],
    ],
];

Log Levels

use Psr\Log\LoggerInterface;

class ProductProcessor
{
    private $logger;

    public function __construct(LoggerInterface $logger)
    {
        $this->logger = $logger;
    }

    public function process($product)
    {
        $this->logger->debug('Processing product', ['sku' => $product->getSku()]);
        
        try {
            // Process product
            $this->logger->info('Product processed successfully', ['id' => $product->getId()]);
        } catch (\Exception $e) {
            $this->logger->error('Product processing failed', [
                'sku' => $product->getSku(),
                'error' => $e->getMessage(),
            ]);
        }
    }
}

Key Points

• system.log records general operations
• exception.log captures uncaught exceptions
• debug.log provides detailed debug info (dev mode)
• Log levels: DEBUG, INFO, NOTICE, WARNING, ERROR, CRITICAL

System Log Usage

use Magento\Framework\Logger\Monolog;

class SystemLogger
{
    private $logger;

    public function __construct(Monolog $logger)
    {
        $this->logger = $logger;
    }

    public function logOrder($orderId, $status)
    {
        $this->logger->info('Order status updated', [
            'order_id' => $orderId,
            'status' => $status,
            'timestamp' => date('Y-m-d H:i:s'),
        ]);
    }

    public function logInventory($sku, $qty)
    {
        $this->logger->warning('Low inventory', [
            'sku' => $sku,
            'quantity' => $qty,
        ]);
    }
}

Exception Logging

// Custom exception handler
set_exception_handler(function($exception) {
    $logger = Bootstrap::getObjectManager()->get(
        \Psr\Log\LoggerInterface::class
    );
    
    $logger->critical('Uncaught exception', [
        'message' => $exception->getMessage(),
        'file' => $exception->getFile(),
        'line' => $exception->getLine(),
        'trace' => $exception->getTraceAsString(),
    ]);
});

// Log specific exception types
try {
    $this->processOrder($order);
} catch (\Magento\Framework\Exception\LocalizedException $e) {
    $this->logger->warning('Localized error: ' . $e->getMessage());
    throw $e;
} catch (\Exception $e) {
    $this->logger->critical('Unexpected error', [
        'exception' => $e,
    ]);
    throw $e;
}

Key Points

• Use appropriate log levels for different events
• Include contextual data in log entries
• Don't log sensitive data (passwords, tokens)
• Monitor exception.log for recurring issues

Custom Logger Channel

// app/code/Vendor/Module/Logger/Handler.php
namespace Vendor\Module\Logger;

use Magento\Framework\Logger\Handler\Base;

class Handler extends Base
{
    protected $fileName = '/var/log/vendor_module.log';
    protected $loggerType = \Monolog\Logger::INFO;
}

// app/code/Vendor/Module/Logger/Handler.xml
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:noNamespaceSchemaLocation="urn:magento:framework:ObjectManager/etc/config.xsd">
    <type name="Magento\Framework\Logger\Monolog">
        <arguments>
            <argument name="handlers" xsi:type="array">
                <item name="debug" xsi:type="object">Vendor\Module\Logger\Handler</item>
            </argument>
        </arguments>
    </type>
</config>

Database Logging

namespace Vendor\Module\Logger;

class DatabaseLogger
{
    private $resource;

    public function __construct(\Magento\Framework\App\ResourceConnection $resource)
    {
        $this->resource = $resource;
    }

    public function log($level, $message, array $context = [])
    {
        $connection = $this->resource->getConnection();
        $tableName = $this->resource->getTableName('vendor_module_log');
        
        $connection->insert($tableName, [
            'level' => $level,
            'message' => $message,
            'context' => json_encode($context),
            'created_at' => date('Y-m-d H:i:s'),
        ]);
    }
}

Key Points

• Create custom handlers for module-specific logs
• Separate logs by module or functionality
• Consider database logging for queryable data
• Implement log rotation to manage disk space

Logrotate Configuration

# /etc/logrotate.d/magento
/var/www/magento/var/log/*.log {
    daily
    missingok
    rotate 14
    compress
    delaycompress
    notifempty
    create 0644 www-data www-data
    sharedscripts
    postrotate
        [ -f /var/run/nginx.pid ] && kill -USR1 $(cat /var/run/nginx.pid)
    endscript
}

Magento Log Cleanup

# Clean old log files
bin/magento log:clean

# Clean specific log types
bin/magento log:clean --log-types=system,exception

# Cron job for automatic cleanup
# bin/magento cron:run (runs log cleanup daily)

Custom Log Cleanup

use Magento\Framework\Log\Cleaner;

class LogCleaner
{
    private $cleaner;

    public function cleanOldLogs($daysToKeep = 30)
    {
        $ cutoff = time() - ($daysToKeep * 86400);
        
        $logFiles = glob('var/log/*.log');
        foreach ($logFiles as $file) {
            if (filemtime($file) < $cutoff) {
                unlink($file);
            }
        }
    }
}

Key Points

• Configure logrotate for automatic rotation
• Set appropriate retention periods
• Compress old log files to save space
• Clean logs regularly to prevent disk filling