LegacyLogger.php

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<?php
namespace MediaWiki\Logger;

use DateTimeZone;
use Error;
use Exception;
use WikiMap;
use MWDebug;
use MWExceptionHandler;
use Psr\Log\AbstractLogger;
use Psr\Log\LogLevel;
use Throwable;
use UDPTransport;

class LegacyLogger extends AbstractLogger {

    protected $channel;

    protected static $levelMapping = [
        LogLevel::DEBUG => 100,
        LogLevel::INFO => 200,
        LogLevel::NOTICE => 250,
        LogLevel::WARNING => 300,
        LogLevel::ERROR => 400,
        LogLevel::CRITICAL => 500,
        LogLevel::ALERT => 550,
        LogLevel::EMERGENCY => 600,
    ];

    protected static $dbChannels = [
        'DBQuery' => true,
        'DBConnection' => true
    ];

    public function __construct( $channel ) {
        $this->channel = $channel;
    }

    public function log( $level, $message, array $context = [] ) {
        global $wgDBerrorLog;

        if ( is_string( $level ) ) {
            $level = self::$levelMapping[$level];
        }
        if ( $this->channel === 'DBQuery'
            && $level === self::$levelMapping[LogLevel::DEBUG]
            && isset( $context['sql'] )
        ) {
            // Also give the query information to the MWDebug tools
            $enabled = MWDebug::query(
                $context['sql'],
                $context['method'],
                $context['runtime'],
                $context['db_host']
            );
            if ( $enabled ) {
                // If we the toolbar was enabled, return early so that we don't
                // also log the query to the main debug output.
                return;
            }
        }

        // 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 $wgMWLoggerDefaultSpi.
        if ( isset( self::$dbChannels[$this->channel] )
            && $level >= self::$levelMapping[LogLevel::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 );
            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 );
        }
    }

    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
            // specfied.
            $shouldEmit = (bool)$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 explictly 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;
    }

    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 ( $channel === 'profileoutput' ) {
            // Legacy wfLogProfilingData formatitng
            $forward = '';
            if ( isset( $context['forwarded_for'] ) ) {
                $forward = " forwarded for {$context['forwarded_for']}";
            }
            if ( isset( $context['client_ip'] ) ) {
                $forward .= " client IP {$context['client_ip']}";
            }
            if ( isset( $context['from'] ) ) {
                $forward .= " from {$context['from']}";
            }
            if ( $forward ) {
                $forward = "\t(proxied via {$context['proxy']}{$forward})";
            }
            if ( $context['anon'] ) {
                $forward .= ' anon';
            }
            if ( !isset( $context['url'] ) ) {
                $context['url'] = 'n/a';
            }

            $log = sprintf( "%s\t%04.3f\t%s%s\n",
                gmdate( 'YmdHis' ), $context['elapsed'], $context['url'], $forward );

            $text = self::formatAsWfDebugLog(
                $channel, $log . $context['output'], $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 exception if available
        if ( $wgLogExceptionBacktrace && isset( $context['exception'] ) ) {
            $e = $context['exception'];
            $backtrace = false;

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

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

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

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

    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";
    }

    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::getWikiIdFromDbDomain( WikiMap::getCurrentWikiDbDomain() );

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

    protected static function formatAsWfDebugLog( $channel, $message, $context ) {
        $time = wfTimestamp( TS_DB );
        $wiki = WikiMap::getWikiIdFromDbDomain( WikiMap::getCurrentWikiDbDomain() );
        $host = wfHostname();
        $text = "{$time} {$host} {$wiki}: {$message}\n";
        return $text;
    }

    public static function interpolate( $message, array $context ) {
        if ( strpos( $message, '{' ) !== false ) {
            $replace = [];
            foreach ( $context as $key => $val ) {
                $replace['{' . $key . '}'] = self::flatten( $val );
            }
            $message = strtr( $message, $replace );
        }
        return $message;
    }

    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 || $item instanceof Exception ) {
            $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 ) . ']';
        }

        if ( is_resource( $item ) ) {
            return '[Resource ' . get_resource_type( $item ) . ']';
        }

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

    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;
    }

    public static function emit( $text, $file ) {
        if ( substr( $file, 0, 4 ) == 'udp:' ) {
            $transport = UDPTransport::newFromString( $file );
            $transport->emit( $text );
        } else {
            \Wikimedia\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 );
            }
            \Wikimedia\restoreWarnings();
        }
    }

}