Logging for PHP: Best Solutions and Libraries

Logging for PHP: Best Solutions

Logging is a crucial part of any serious PHP application. It helps track errors, analyze user behavior, conduct security audits, and debug code. In this article, we will review the best libraries for logging in PHP, their features, and usage examples.

Why is logging necessary?

Without logging, a developer often remains "blind" when problems arise. A quality logging system allows you to:

• Quickly find and fix errors in a production environment
• Collect statistics and analyze performance
• Ensure compliance with security standards (PCI DSS, GDPR)
• Monitor suspicious activity

The PSR-3 Standard (Logger Interface)

Most modern PHP libraries follow the PSR-3 standard, which defines a unified interface for loggers. This allows you to easily replace one library with another without changing the application code.

Main logging levels according to PSR-3:

• emergency — system is unusable
• alert — immediate action is required
• critical — critical error
• error — error that does not require immediate intervention
• warning — warning
• notice — normal but significant event
• info — informational message
• debug — debug information

Best Libraries for Logging in PHP

1. Monolog

Monolog is the de facto standard for logging in PHP. It supports PSR-3 and has a huge number of "handlers" and "formatters". It is installed via Composer:

composer require monolog/monolog

Basic usage example:

<?phpuse Monolog\\Logger;use Monolog\\Handler\\StreamHandler;

$log = new Logger('my_app');$log->pushHandler(new StreamHandler('/var/log/app.log', Logger::WARNING));

$log->warning('Warning: request limit exceeded');$log->error('Database connection error', ['db' => 'mysql', 'time' => 0.5]);?>

Monolog supports sending logs to files, databases, Slack, Telegram, Email, Syslog, and many other channels. Its flexible architecture allows you to create custom handlers.

2. Analog

Analog is a lightweight and fast library focused on simplicity. It requires no dependencies and is ideal for small projects.

<?phprequire_once 'Analog.php';

Analog::handler(Analog\\Handler\\File::init('/var/log/app.log'));Analog::log('Page loaded', Analog::INFO);?>

Analog supports the same logging levels as PSR-3 but has its own API. For PSR-3 integration, you can use the AnalogPSR3 bridge.

3. KLogger

KLogger is a minimalist library that was once popular. Its development has now stopped, but it is still used in older projects. Example:

<?php$log = new Katzgrau\\KLogger\\Logger('/var/log/');$log->info('User logged in');?>

Not recommended for new projects due to the lack of PSR-3 support and updates.

4. Log4php

Log4php is a port of the popular Java framework Log4j. It supports complex configurations via XML or PHP arrays:

<?phprequire_once 'Logger.php';Logger::configure('config.xml');

$logger = Logger::getLogger('main');$logger->error('Critical error');?>

Log4php has a steep learning curve but provides powerful features: filtering, multiple appenders, macros.