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[mediawiki.git] / includes / debug / logger / LegacyLogger.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;

use DateTimeZone;
use Error;
use LogicException;
use MediaWiki\Debug\MWDebug;
use MediaWiki\WikiMap\WikiMap;
use MWExceptionHandler;
use Psr\Log\AbstractLogger;
use Psr\Log\LogLevel;
use Throwable;
use UDPTransport;
use Wikimedia\AtEase\AtEase;

/**
 * PSR-3 logger that mimics the historic implementation of MediaWiki's former
 * wfErrorLog logging implementation.
 *
 * This logger is configured by the following global configuration variables:
 * - `$wgDebugLogFile`
 * - `$wgDebugLogGroups`
 * - `$wgDBerrorLog`
 * - `$wgDBerrorLogTZ`
 *
 * See docs/Configuration.md for detailed explanations of these settings.
 *
 * @see \MediaWiki\Logger\LoggerFactory
 * @since 1.25
 * @ingroup Debug
 * @copyright © 2014 Wikimedia Foundation and contributors
 */
class LegacyLogger extends AbstractLogger {

        /**
         * @var string
         */
        protected $channel;

        private const LEVEL_DEBUG = 100;
        private const LEVEL_INFO = 200;
        private const LEVEL_NOTICE = 250;
        private const LEVEL_WARNING = 300;
        private const LEVEL_ERROR = 400;
        private const LEVEL_CRITICAL = 500;
        private const LEVEL_ALERT = 550;
        private const LEVEL_EMERGENCY = 600;
        private const LEVEL_INFINITY = 999;

        /**
         * Convert \Psr\Log\LogLevel constants into int for sensible comparisons
         * These are the same values that Monolog uses
         *
         * @var array
         */
        protected static $levelMapping = [
                LogLevel::DEBUG => self::LEVEL_DEBUG,
                LogLevel::INFO => self::LEVEL_INFO,
                LogLevel::NOTICE => self::LEVEL_NOTICE,
                LogLevel::WARNING => self::LEVEL_WARNING,
                LogLevel::ERROR => self::LEVEL_ERROR,
                LogLevel::CRITICAL => self::LEVEL_CRITICAL,
                LogLevel::ALERT => self::LEVEL_ALERT,
                LogLevel::EMERGENCY => self::LEVEL_EMERGENCY,
        ];

        /**
         * Minimum level. This is just to allow faster discard of debugging
         * messages. Not all messages meeting the level will be logged.
         *
         * @var int
         */
        private $minimumLevel;

        /**
         * Whether the channel is a DB channel
         *
         * @var bool
         */
        private $isDB;

        /**
         * @param string $channel
         */
        public function __construct( $channel ) {
                global $wgDebugLogFile, $wgDBerrorLog, $wgDebugLogGroups, $wgDebugToolbar, $wgDebugRawPage, $wgShowDebug;

                $this->channel = $channel;
                $this->isDB = ( $channel === 'rdbms' );

                // Calculate minimum level, duplicating some of the logic from log() and shouldEmit()
                if ( !$wgDebugRawPage && wfIsDebugRawPage() ) {
                        $this->minimumLevel = self::LEVEL_WARNING;
                } elseif ( $wgDebugLogFile != '' || $wgShowDebug || $wgDebugToolbar ) {
                        // Log all messages if there is a debug log file or debug toolbar
                        $this->minimumLevel = self::LEVEL_DEBUG;
                } elseif ( isset( $wgDebugLogGroups[$channel] ) ) {
                        $logConfig = $wgDebugLogGroups[$channel];
                        // Log messages if the config is set, according to the configured level
                        if ( is_array( $logConfig ) && isset( $logConfig['level'] ) ) {
                                $this->minimumLevel = self::$levelMapping[$logConfig['level']];
                        } else {
                                $this->minimumLevel = self::LEVEL_DEBUG;
                        }
                } else {
                        // No other case hit: discard all messages
                        $this->minimumLevel = self::LEVEL_INFINITY;
                }

                if ( $this->isDB && $wgDBerrorLog && $this->minimumLevel > self::LEVEL_ERROR ) {
                        // Log DB errors if there is a DB error log
                        $this->minimumLevel = self::LEVEL_ERROR;
                }
        }

        /**
         * Change an existing Logger singleton to act like NullLogger.
         *
         * @internal For use by MediaWikiIntegrationTestCase::setNullLogger
         * @param null|int $level
         * @return int
         */
        public function setMinimumForTest( ?int $level ) {
                if ( !defined( 'MW_PHPUNIT_TEST' ) ) {
                        throw new LogicException( 'Not allowed outside tests' );
                }
                // Set LEVEL_INFINITY if given null, or restore the original level.
                $original = $this->minimumLevel;
                $this->minimumLevel = $level ?? self::LEVEL_INFINITY;
                return $original;
        }

        /**
         * Logs with an arbitrary level.
         *
         * @param string|int $level
         * @param string $message
         * @param array $context
         */
        public function log( $level, $message, array $context = [] ) {
                if ( is_string( $level ) ) {
                        $level = self::$levelMapping[$level];
                }
                if ( $level < $this->minimumLevel ) {
                        return;
                }

                if ( $this->isDB
                        && $level === self::LEVEL_DEBUG
                        && isset( $context['sql'] )
                ) {
                        // Also give the query information to the MWDebug tools
                        MWDebug::query(
                                $context['sql'],
                                $context['method'],
                                $context['runtime_ms'] / 1000,
                                $context['db_server']
                        );
                }

                // If this is a DB-related error, and the site has $wgDBerrorLog
                // configured, rewrite the channel as wfLogDBError instead.
                // Likewise, if the site does not use  $wgDBerrorLog, it should
                // configurable like any other channel via $wgDebugLogGroups
                // or $wgMWLoggerDefaultSpi.
                global $wgDBerrorLog;
                if ( $this->isDB && $level >= self::LEVEL_ERROR && $wgDBerrorLog ) {
                        // Format and write DB errors to the legacy locations
                        $effectiveChannel = 'wfLogDBError';
                } else {
                        $effectiveChannel = $this->channel;
                }

                if ( self::shouldEmit( $effectiveChannel, $message, $level, $context ) ) {
                        $text = self::format( $effectiveChannel, $message, $context );
                        $destination = self::destination( $effectiveChannel, $message, $context );
                        $this->maybeLogToStderr( $text );
                        self::emit( $text, $destination );
                }
                if ( !isset( $context['private'] ) || !$context['private'] ) {
                        // Add to debug toolbar if not marked as "private"
                        MWDebug::debugMsg( $message, [ 'channel' => $this->channel ] + $context );
                }
        }

        /**
         * Determine if the given message should be emitted or not.
         *
         * @param string $channel
         * @param string $message
         * @param string|int $level \Psr\Log\LogEvent constant or Monolog level int
         * @param array $context
         * @return bool True if message should be sent to disk/network, false
         * otherwise
         */
        public static function shouldEmit( $channel, $message, $level, $context ) {
                global $wgDebugLogFile, $wgDBerrorLog, $wgDebugLogGroups;

                if ( is_string( $level ) ) {
                        $level = self::$levelMapping[$level];
                }

                if ( $channel === 'wfLogDBError' ) {
                        // wfLogDBError messages are emitted if a database log location is
                        // specified.
                        $shouldEmit = (bool)$wgDBerrorLog;

                } elseif ( $channel === 'wfDebug' ) {
                        // wfDebug messages are emitted if a catch all logging file has
                        // been specified. Checked explicitly so that 'private' flagged
                        // messages are not discarded by unset $wgDebugLogGroups channel
                        // handling below.
                        $shouldEmit = $wgDebugLogFile != '';

                } elseif ( isset( $wgDebugLogGroups[$channel] ) ) {
                        $logConfig = $wgDebugLogGroups[$channel];

                        if ( is_array( $logConfig ) ) {
                                $shouldEmit = true;
                                if ( isset( $logConfig['sample'] ) ) {
                                        // Emit randomly with a 1 in 'sample' chance for each message.
                                        $shouldEmit = mt_rand( 1, $logConfig['sample'] ) === 1;
                                }

                                if ( isset( $logConfig['level'] ) ) {
                                        $shouldEmit = $level >= self::$levelMapping[$logConfig['level']];
                                }
                        } else {
                                // Emit unless the config value is explicitly false.
                                $shouldEmit = $logConfig !== false;
                        }

                } elseif ( isset( $context['private'] ) && $context['private'] ) {
                        // Don't emit if the message didn't match previous checks based on
                        // the channel and the event is marked as private. This check
                        // discards messages sent via wfDebugLog() with dest == 'private'
                        // and no explicit wgDebugLogGroups configuration.
                        $shouldEmit = false;
                } else {
                        // Default return value is the same as the historic wfDebug
                        // method: emit if $wgDebugLogFile has been set.
                        $shouldEmit = $wgDebugLogFile != '';
                }

                return $shouldEmit;
        }

        /**
         * Format a message.
         *
         * Messages to the 'wfDebug' and 'wfLogDBError' channels receive special formatting to mimic the
         * historic output of the functions of the same name. All other channel values are formatted
         * based on the historic output of the `wfDebugLog()` global function.
         *
         * @param string $channel
         * @param string $message
         * @param array $context
         * @return string
         */
        public static function format( $channel, $message, $context ) {
                global $wgDebugLogGroups, $wgLogExceptionBacktrace;

                if ( $channel === 'wfDebug' ) {
                        $text = self::formatAsWfDebug( $channel, $message, $context );

                } elseif ( $channel === 'wfLogDBError' ) {
                        $text = self::formatAsWfLogDBError( $channel, $message, $context );

                } elseif ( !isset( $wgDebugLogGroups[$channel] ) ) {
                        $text = self::formatAsWfDebug(
                                $channel, "[{$channel}] {$message}", $context );

                } else {
                        // Default formatting is wfDebugLog's historic style
                        $text = self::formatAsWfDebugLog( $channel, $message, $context );
                }

                // Append stacktrace of throwable if available
                if ( $wgLogExceptionBacktrace && isset( $context['exception'] ) ) {
                        $e = $context['exception'];
                        $backtrace = false;

                        if ( $e instanceof Throwable ) {
                                $backtrace = MWExceptionHandler::getRedactedTrace( $e );

                        } elseif ( is_array( $e ) && isset( $e['trace'] ) ) {
                                // Throwable has already been unpacked as structured data
                                $backtrace = $e['trace'];
                        }

                        if ( $backtrace ) {
                                $text .= MWExceptionHandler::prettyPrintTrace( $backtrace ) .
                                        "\n";
                        }
                }

                return self::interpolate( $text, $context );
        }

        /**
         * Format a message as `wfDebug()` would have formatted it.
         *
         * @param string $channel
         * @param string $message
         * @param array $context
         * @return string
         */
        protected static function formatAsWfDebug( $channel, $message, $context ) {
                $text = preg_replace( '![\x00-\x08\x0b\x0c\x0e-\x1f]!', ' ', $message );
                if ( isset( $context['seconds_elapsed'] ) ) {
                        // Prepend elapsed request time and real memory usage with two
                        // trailing spaces.
                        $text = "{$context['seconds_elapsed']} {$context['memory_used']}  {$text}";
                }
                if ( isset( $context['prefix'] ) ) {
                        $text = "{$context['prefix']}{$text}";
                }
                return "{$text}\n";
        }

        /**
         * Format a message as `wfLogDBError()` would have formatted it.
         *
         * @param string $channel
         * @param string $message
         * @param array $context
         * @return string
         */
        protected static function formatAsWfLogDBError( $channel, $message, $context ) {
                global $wgDBerrorLogTZ;
                static $cachedTimezone = null;

                if ( !$cachedTimezone ) {
                        $cachedTimezone = new DateTimeZone( $wgDBerrorLogTZ );
                }

                $d = date_create( 'now', $cachedTimezone );
                $date = $d->format( 'D M j G:i:s T Y' );

                $host = wfHostname();
                $wiki = WikiMap::getCurrentWikiId();

                $text = "{$date}\t{$host}\t{$wiki}\t{$message}\n";
                return $text;
        }

        /**
         * Format a message as `wfDebugLog() would have formatted it.
         *
         * @param string $channel
         * @param string $message
         * @param array $context
         * @return string
         */
        protected static function formatAsWfDebugLog( $channel, $message, $context ) {
                $time = wfTimestamp( TS_DB );
                $wiki = WikiMap::getCurrentWikiId();
                $host = wfHostname();
                $text = "{$time} {$host} {$wiki}: {$message}\n";
                return $text;
        }

        /**
         * Interpolate placeholders in logging message.
         *
         * @param string $message
         * @param array $context
         * @return string Interpolated message
         */
        public static function interpolate( $message, array $context ) {
                if ( str_contains( $message, '{' ) ) {
                        $replace = [];
                        foreach ( $context as $key => $val ) {
                                $replace['{' . $key . '}'] = self::flatten( $val );
                        }
                        $message = strtr( $message, $replace );
                }
                return $message;
        }

        /**
         * Convert a logging context element to a string suitable for
         * interpolation.
         *
         * @param mixed $item
         * @return string
         */
        protected static function flatten( $item ) {
                if ( $item === null ) {
                        return '[Null]';
                }

                if ( is_bool( $item ) ) {
                        return $item ? 'true' : 'false';
                }

                if ( is_float( $item ) ) {
                        if ( is_infinite( $item ) ) {
                                return ( $item > 0 ? '' : '-' ) . 'INF';
                        }
                        if ( is_nan( $item ) ) {
                                return 'NaN';
                        }
                        return (string)$item;
                }

                if ( is_scalar( $item ) ) {
                        return (string)$item;
                }

                if ( is_array( $item ) ) {
                        return '[Array(' . count( $item ) . ')]';
                }

                if ( $item instanceof \DateTime ) {
                        return $item->format( 'c' );
                }

                if ( $item instanceof Throwable ) {
                        $which = $item instanceof Error ? 'Error' : 'Exception';
                        return '[' . $which . ' ' . get_class( $item ) . '( ' .
                                $item->getFile() . ':' . $item->getLine() . ') ' .
                                $item->getMessage() . ']';
                }

                if ( is_object( $item ) ) {
                        if ( method_exists( $item, '__toString' ) ) {
                                return (string)$item;
                        }

                        return '[Object ' . get_class( $item ) . ']';
                }

                // phpcs:ignore MediaWiki.Usage.ForbiddenFunctions.is_resource
                if ( is_resource( $item ) ) {
                        return '[Resource ' . get_resource_type( $item ) . ']';
                }

                return '[Unknown ' . get_debug_type( $item ) . ']';
        }

        /**
         * Select the appropriate log output destination for the given log event.
         *
         * If the event context contains 'destination'
         *
         * @param string $channel
         * @param string $message
         * @param array $context
         * @return string
         */
        protected static function destination( $channel, $message, $context ) {
                global $wgDebugLogFile, $wgDBerrorLog, $wgDebugLogGroups;

                // Default destination is the debug log file as historically used by
                // the wfDebug function.
                $destination = $wgDebugLogFile;

                if ( isset( $context['destination'] ) ) {
                        // Use destination explicitly provided in context
                        $destination = $context['destination'];

                } elseif ( $channel === 'wfDebug' ) {
                        $destination = $wgDebugLogFile;

                } elseif ( $channel === 'wfLogDBError' ) {
                        $destination = $wgDBerrorLog;

                } elseif ( isset( $wgDebugLogGroups[$channel] ) ) {
                        $logConfig = $wgDebugLogGroups[$channel];

                        if ( is_array( $logConfig ) ) {
                                $destination = $logConfig['destination'];
                        } else {
                                $destination = strval( $logConfig );
                        }
                }

                return $destination;
        }

        /**
         * Log to a file without getting "file size exceeded" signals.
         *
         * Can also log to UDP with the syntax udp://host:port/prefix. This will send
         * lines to the specified port, prefixed by the specified prefix and a space.
         *
         * @param string $text
         * @param string $file Filename
         */
        public static function emit( $text, $file ) {
                if ( str_starts_with( $file, 'udp:' ) ) {
                        $transport = UDPTransport::newFromString( $file );
                        $transport->emit( $text );
                } else {
                        AtEase::suppressWarnings();
                        $exists = file_exists( $file );
                        $size = $exists ? filesize( $file ) : false;
                        if ( !$exists ||
                                ( $size !== false && $size + strlen( $text ) < 0x7fffffff )
                        ) {
                                file_put_contents( $file, $text, FILE_APPEND );
                        }
                        AtEase::restoreWarnings();
                }
        }

        /**
         * If MW_LOG_STDERR is set (used currently in `composer serve`) then also
         * emit to stderr using error_log().
         *
         * @param string $text
         * @return void
         */
        private function maybeLogToStderr( string $text ): void {
                if ( getenv( 'MW_LOG_STDERR' ) ) {
                        error_log( trim( $text ) );
                }
        }

}