Merge "Remove not used private member variable mParserWarnings from OutputPage"

[mediawiki.git] / includes / debug / logger / monolog / KafkaHandler.php

<?php
/**
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 * http://www.gnu.org/copyleft/gpl.html
 *
 * @file
 */

namespace MediaWiki\Logger\Monolog;

use Kafka\MetaDataFromKafka;
use Kafka\Produce;
use MediaWiki\Logger\LoggerFactory;
use Monolog\Handler\AbstractProcessingHandler;
use Monolog\Logger;
use Psr\Log\LoggerInterface;

/**
 * Log handler sends log events to a kafka server.
 *
 * Constructor options array arguments:
 * * alias: map from monolog channel to kafka topic name. When no
 *        alias exists the topic "monolog_$channel" will be used.
 * * swallowExceptions: Swallow exceptions that occur while talking to
 *    kafka. Defaults to false.
 * * logExceptions: Log exceptions talking to kafka here. Either null,
 *    the name of a channel to log to, or an object implementing
 *    FormatterInterface. Defaults to null.
 *
 * Requires the nmred/kafka-php library, version >= 1.3.0
 *
 * @since 1.26
 * @author Erik Bernhardson <ebernhardson@wikimedia.org>
 * @copyright © 2015 Erik Bernhardson and Wikimedia Foundation.
 */
class KafkaHandler extends AbstractProcessingHandler {
        /**
         * @var Produce Sends requests to kafka
         */
        protected $produce;

        /**
         * @var array Optional handler configuration
         */
        protected $options;

        /**
         * @var array Map from topic name to partition this request produces to
         */
        protected $partitions = array();

        /**
         * @var array defaults for constructor options
         */
        private static $defaultOptions = array(
                'alias' => array(), // map from monolog channel to kafka topic
                'swallowExceptions' => false, // swallow exceptions sending records
                'logExceptions' => null, // A PSR3 logger to inform about errors
        );

        /**
         * @param Produce $produce Kafka instance to produce through
         * @param array $options optional handler configuration
         * @param int $level The minimum logging level at which this handler will be triggered
         * @param bool $bubble Whether the messages that are handled can bubble up the stack or not
         */
        public function __construct(
                Produce $produce, array $options, $level = Logger::DEBUG, $bubble = true
        ) {
                parent::__construct( $level, $bubble );
                $this->produce = $produce;
                $this->options = array_merge( self::$defaultOptions, $options );
        }

        /**
         * Constructs the necessary support objects and returns a KafkaHandler
         * instance.
         *
         * @param string[] $kafkaServers
         * @param array $options
         * @param int $level The minimum logging level at which this handle will be triggered
         * @param bool $bubble Whether the messages that are handled can bubble the stack or not
         * @return KafkaHandler
         */
        public static function factory(
                $kafkaServers, array $options = array(), $level = Logger::DEBUG, $bubble = true
        ) {
                $metadata = new MetaDataFromKafka( $kafkaServers );
                $produce = new Produce( $metadata );
                if ( isset( $options['logExceptions'] ) && is_string( $options['logExceptions'] ) ) {
                        $options['logExceptions'] = LoggerFactory::getInstance( $options['logExceptions'] );
                }
                return new self( $produce, $options, $level, $bubble );
        }

        /**
         * {@inheritDoc}
         */
        protected function write( array $record ) {
                if ( $record['formatted'] !== null ) {
                        $this->addMessages( $record['channel'], array( $record['formatted'] ) );
                        $this->send();
                }
        }

        /**
         * {@inheritDoc}
         */
        public function handleBatch( array $batch ) {
                $channels = array();
                foreach ( $batch as $record ) {
                        if ( $record['level'] < $this->level ) {
                                continue;
                        }
                        $channels[$record['channel']][] = $this->processRecord( $record );
                }

                $formatter = $this->getFormatter();
                foreach ( $channels as $channel => $records ) {
                        $messages = array();
                        foreach ( $records as $idx => $record ) {
                                $message = $formatter->format( $record );
                                if ( $message !== null ) {
                                        $messages[] = $message;
                                }
                        }
                        if ( $messages ) {
                                $this->addMessages( $channel, $messages );
                        }
                }

                $this->send();
        }

        /**
         * Send any records in the kafka client internal queue.
         */
        protected function send() {
                try {
                        $this->produce->send();
                } catch ( \Kafka\Exception $e ) {
                        $ignore = $this->warning(
                                'Error sending records to kafka: {exception}',
                                array( 'exception' => $e ) );
                        if ( !$ignore ) {
                                throw $e;
                        }
                }
        }

        /**
         * @param string $topic Name of topic to get partition for
         * @return int|null The random partition to produce to for this request,
         *  or null if a partition could not be determined.
         */
        protected function getRandomPartition( $topic ) {
                if ( !array_key_exists( $topic, $this->partitions ) ) {
                        try {
                                $partitions = $this->produce->getAvailablePartitions( $topic );
                        } catch ( \Kafka\Exception $e ) {
                                $ignore = $this->warning(
                                        'Error getting metadata for kafka topic {topic}: {exception}',
                                        array( 'topic' => $topic, 'exception' => $e ) );
                                if ( $ignore ) {
                                        return null;
                                }
                                throw $e;
                        }
                        if ( $partitions ) {
                                $key = array_rand( $partitions );
                                $this->partitions[$topic] = $partitions[$key];
                        } else {
                                $details = $this->produce->getClient()->getTopicDetail( $topic );
                                $ignore = $this->warning(
                                        'No partitions available for kafka topic {topic}',
                                        array( 'topic' => $topic, 'kafka' => $details )
                                );
                                if ( !$ignore ) {
                                        throw new \RuntimeException( "No partitions available for kafka topic $topic" );
                                }
                                $this->partitions[$topic] = null;
                        }
                }
                return $this->partitions[$topic];
        }

        /**
         * Adds records for a channel to the Kafka client internal queue.
         *
         * @param string $channel Name of Monolog channel records belong to
         * @param array $records List of records to append
         */
        protected function addMessages( $channel, array $records ) {
                if ( isset( $this->options['alias'][$channel] ) ) {
                        $topic = $this->options['alias'][$channel];
                } else {
                        $topic = "monolog_$channel";
                }
                $partition = $this->getRandomPartition( $topic );
                if ( $partition !== null ) {
                        $this->produce->setMessages( $topic, $partition, $records );
                }
        }

        /**
         * @param string $message PSR3 compatible message string
         * @param array $context PSR3 compatible log context
         * @return bool true if caller should ignore warning
         */
        protected function warning( $message, array $context = array() ) {
                if ( $this->options['logExceptions'] instanceof LoggerInterface ) {
                        $this->options['logExceptions']->warning( $message, $context );
                }
                return $this->options['swallowExceptions'];
        }
}