<?php



/*

 * This file is part of the Monolog package.

 *

 * (c) Jordi Boggiano <j.boggiano@seld.be>

 *

 * For the full copyright and license information, please view the LICENSE

 * file that was distributed with this source code.

 */



namespace Monolog\Formatter;



use Monolog\Logger;

use Gelf\Message;



/**

 * Serializes a log message to GELF

 * @see http://www.graylog2.org/about/gelf

 *

 * @author Matt Lehner <mlehner@gmail.com>

 */

class GelfMessageFormatter extends NormalizerFormatter

{

    const DEFAULT_MAX_LENGTH = 32766;



    /**

     * @var string the name of the system for the Gelf log message

     */

    protected $systemName;



    /**

     * @var string a prefix for 'extra' fields from the Monolog record (optional)

     */

    protected $extraPrefix;



    /**

     * @var string a prefix for 'context' fields from the Monolog record (optional)

     */

    protected $contextPrefix;



    /**

     * @var int max length per field

     */

    protected $maxLength;



    /**

     * Translates Monolog log levels to Graylog2 log priorities.

     */

    private $logLevels = array(

        Logger::DEBUG     => 7,

        Logger::INFO      => 6,

        Logger::NOTICE    => 5,

        Logger::WARNING   => 4,

        Logger::ERROR     => 3,

        Logger::CRITICAL  => 2,

        Logger::ALERT     => 1,

        Logger::EMERGENCY => 0,

    );



    public function __construct($systemName = null, $extraPrefix = null, $contextPrefix = 'ctxt_', $maxLength = null)

    {

        parent::__construct('U.u');



        $this->systemName = $systemName ?: gethostname();



        $this->extraPrefix = $extraPrefix;

        $this->contextPrefix = $contextPrefix;

        $this->maxLength = is_null($maxLength) ? self::DEFAULT_MAX_LENGTH : $maxLength;

    }



    /**

     * {@inheritdoc}

     */

    public function format(array $record)

    {

        $record = parent::format($record);



        if (!isset($record['datetime'], $record['message'], $record['level'])) {

            throw new \InvalidArgumentException('The record should at least contain datetime, message and level keys, '.var_export($record, true).' given');

        }



        $message = new Message();

        $message

            ->setTimestamp($record['datetime'])

            ->setShortMessage((string) $record['message'])

            ->setHost($this->systemName)

            ->setLevel($this->logLevels[$record['level']]);



        // message length + system name length + 200 for padding / metadata 

        $len = 200 + strlen((string) $record['message']) + strlen($this->systemName);



        if ($len > $this->maxLength) {

            $message->setShortMessage(substr($record['message'], 0, $this->maxLength));

        }



        if (isset($record['channel'])) {

            $message->setFacility($record['channel']);

        }

        if (isset($record['extra']['line'])) {

            $message->setLine($record['extra']['line']);

            unset($record['extra']['line']);

        }

        if (isset($record['extra']['file'])) {

            $message->setFile($record['extra']['file']);

            unset($record['extra']['file']);

        }



        foreach ($record['extra'] as $key => $val) {

            $val = is_scalar($val) || null === $val ? $val : $this->toJson($val);

            $len = strlen($this->extraPrefix . $key . $val);

            if ($len > $this->maxLength) {

                $message->setAdditional($this->extraPrefix . $key, substr($val, 0, $this->maxLength));

                break;

            }

            $message->setAdditional($this->extraPrefix . $key, $val);

        }



        foreach ($record['context'] as $key => $val) {

            $val = is_scalar($val) || null === $val ? $val : $this->toJson($val);

            $len = strlen($this->contextPrefix . $key . $val);

            if ($len > $this->maxLength) {

                $message->setAdditional($this->contextPrefix . $key, substr($val, 0, $this->maxLength));

                break;

            }

            $message->setAdditional($this->contextPrefix . $key, $val);

        }



        if (null === $message->getFile() && isset($record['context']['exception']['file'])) {

            if (preg_match("/^(.+):([0-9]+)$/", $record['context']['exception']['file'], $matches)) {

                $message->setFile($matches[1]);

                $message->setLine($matches[2]);

            }

        }



        return $message;

    }

}

