Quick Start

Quick Start

This page walks you from a fresh composer require to a working logger in under five minutes. If you have not installed the package yet, start with Installation.

Choose a handler

The package ships two concrete handlers and one multiplexer. Pick whichever matches your storage need; they all expose the identical PSR-3 surface.

You want to…	Use…
append log lines to a local file	FileLogger
insert log rows into a database	PDOLogger
do both at once (or combine any PSR-3 handlers)	Logger
send logs somewhere else (syslog, Slack, in-memory buffer…)	a Custom Handler

File logging in three lines

<?php
require __DIR__ . '/vendor/autoload.php';

use InitPHP\Logger\FileLogger;

$logger = new FileLogger(['path' => __DIR__ . '/logs/app.log']);

$logger->info('Hello from InitPHP Logger');

Run the script. You should now see:

$ cat logs/app.log
2026-05-24T14:08:22+03:00 [INFO] Hello from InitPHP Logger

The logs/ directory is created automatically; you do not have to mkdir it manually. Each call writes exactly one line ending with PHP_EOL.

Database logging

PDOLogger requires you to supply a configured PDO instance and the name of a table that has at minimum level, message and date columns.

CREATE TABLE logs (
    id      BIGINT UNSIGNED AUTO_INCREMENT PRIMARY KEY,
    level   VARCHAR(10) NOT NULL,
    message TEXT NOT NULL,
    date    DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP
);

<?php
require __DIR__ . '/vendor/autoload.php';

use InitPHP\Logger\PDOLogger;

$pdo = new PDO('mysql:host=localhost;dbname=app;charset=utf8mb4', 'app', 'secret', [
    PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION,
]);

$logger = new PDOLogger(['pdo' => $pdo, 'table' => 'logs']);

$logger->error('User {user} caused an error.', ['user' => 'jane']);

After the call:

level	message	date
ERROR	User jane caused an error.	2026-05-24 14:08:22

Full schema variants for MySQL / PostgreSQL / SQLite are in PDOLogger › DDL examples.

Multi-handler logging

Logger accepts any number of PSR-3 handlers and forwards every call to all of them, in registration order.

<?php
require __DIR__ . '/vendor/autoload.php';

use InitPHP\Logger\FileLogger;
use InitPHP\Logger\Logger;
use InitPHP\Logger\PDOLogger;

$pdo = new PDO('mysql:host=localhost;dbname=app', 'app', 'secret', [
    PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION,
]);

$logger = new Logger(
    new FileLogger(['path' => __DIR__ . '/logs/app.log']),
    new PDOLogger(['pdo' => $pdo, 'table' => 'logs'])
);

$logger->warning('cache miss for key {key}', ['key' => 'user:42']);
// → goes to BOTH the log file and the logs table

Every PSR-3 method works the same way through the multiplexer; see Multi-Logger for ordering, fault isolation, and exception semantics.

All eight PSR-3 levels

The package exposes the full PSR-3 surface — eight severity helpers plus the generic log() method:

$logger->emergency('system unusable');
$logger->alert    ('action required immediately');
$logger->critical ('critical condition');
$logger->error    ('runtime error');
$logger->warning  ('exceptional condition, not an error');
$logger->notice   ('normal but significant');
$logger->info     ('informational');
$logger->debug    ('debug-level detail');

// Equivalent low-level form:
$logger->log(\Psr\Log\LogLevel::ERROR, 'runtime error');

Unknown levels throw \Psr\Log\InvalidArgumentException. The package normalises levels to uppercase in its output (ERROR, WARNING, …); inputs are matched case-insensitively against the eight PSR-3 constants.

Inject LoggerInterface, not a concrete class

The whole point of PSR-3 is that consumers depend on the interface:

use Psr\Log\LoggerInterface;

final class PaymentService
{
    public function __construct(private LoggerInterface $logger) {}

    public function charge(int $userId): void
    {
        $this->logger->info('charging user {id}', ['id' => $userId]);
    }
}

Anyone can pass a FileLogger, a PDOLogger, a Logger, a NullLogger in tests, Monolog, or their own handler. Your service does not need to know.

Where to go next

• Detailed handler docs: FileLogger · PDOLogger · Multi-Logger · Custom Handlers
• PSR-3 specifics: PSR-3 Compliance, Context Interpolation, Error Handling
• Real-world patterns: Recipes
• Writing tests against the logger: Testing Your Logging
• Full method reference: API Reference