src/Symfony/Component/HttpKernel/Log/Logger.php

<?php

/*
 * This file is part of the Symfony package.
 *
 * (c) Fabien Potencier <fabien@symfony.com>
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

namespace Symfony\Component\HttpKernel\Log;

use Psr\Log\AbstractLogger;
use Psr\Log\InvalidArgumentException;
use Psr\Log\LogLevel;

/**
 * Minimalist PSR-3 logger designed to write in stderr or any other stream.
 *
 * @author Kévin Dunglas <dunglas@gmail.com>
 */
class Logger extends AbstractLogger
{
    private static $levels = [
        LogLevel::DEBUG => 0,
        LogLevel::INFO => 1,
        LogLevel::NOTICE => 2,
        LogLevel::WARNING => 3,
        LogLevel::ERROR => 4,
        LogLevel::CRITICAL => 5,
        LogLevel::ALERT => 6,
        LogLevel::EMERGENCY => 7,
    ];

    private $minLevelIndex;
    private $formatter;
    private $handle;

    public function __construct(string $minLevel = null, $output = null, callable $formatter = null)
    {
        if (null === $minLevel) {
            $minLevel = null === $output || 'php://stdout' === $output || 'php://stderr' === $output ? LogLevel::ERROR : LogLevel::WARNING;

            if (isset($_ENV['SHELL_VERBOSITY']) || isset($_SERVER['SHELL_VERBOSITY'])) {
                switch ((int) (isset($_ENV['SHELL_VERBOSITY']) ? $_ENV['SHELL_VERBOSITY'] : $_SERVER['SHELL_VERBOSITY'])) {
                    case -1: $minLevel = LogLevel::ERROR; break;
                    case 1: $minLevel = LogLevel::NOTICE; break;
                    case 2: $minLevel = LogLevel::INFO; break;
                    case 3: $minLevel = LogLevel::DEBUG; break;
                }
            }
        }

        if (!isset(self::$levels[$minLevel])) {
            throw new InvalidArgumentException(sprintf('The log level "%s" does not exist.', $minLevel));
        }

        $this->minLevelIndex = self::$levels[$minLevel];
        $this->formatter = $formatter ?: [$this, 'format'];
        if ($output && false === $this->handle = \is_resource($output) ? $output : @fopen($output, 'a')) {
            throw new InvalidArgumentException(sprintf('Unable to open "%s".', $output));
        }
    }

    /**
     * {@inheritdoc}
     *
     * @return void
     */
    public function log($level, $message, array $context = [])
    {
        if (!isset(self::$levels[$level])) {
            throw new InvalidArgumentException(sprintf('The log level "%s" does not exist.', $level));
        }

        if (self::$levels[$level] < $this->minLevelIndex) {
            return;
        }

        $formatter = $this->formatter;
        if ($this->handle) {
            @fwrite($this->handle, $formatter($level, $message, $context));
        } else {
            error_log($formatter($level, $message, $context, false));
        }
    }

    private function format(string $level, string $message, array $context, bool $prefixDate = true): string
    {
        if (false !== strpos($message, '{')) {
            $replacements = [];
            foreach ($context as $key => $val) {
                if (null === $val || is_scalar($val) || (\is_object($val) && method_exists($val, '__toString'))) {
                    $replacements["{{$key}}"] = $val;
                } elseif ($val instanceof \DateTimeInterface) {
                    $replacements["{{$key}}"] = $val->format(\DateTime::RFC3339);
                } elseif (\is_object($val)) {
                    $replacements["{{$key}}"] = '[object '.\get_class($val).']';
                } else {
                    $replacements["{{$key}}"] = '['.\gettype($val).']';
                }
            }

            $message = strtr($message, $replacements);
        }

        $log = sprintf('[%s] %s', $level, $message).\PHP_EOL;
        if ($prefixDate) {
            $log = date(\DateTime::RFC3339).' '.$log;
        }

        return $log;
    }
}