<?php
# WARNING: This file is publicly viewable on the web. Do not put private data here.

# logging.php holds the shared logging configuration. Beware of falling trees.
#
# This for PRODUCTION.
#
# Effective load order:
# - multiversion
# - mediawiki/DefaultSettings.php
# - wmf-config/*Services.php
# - wmf-config/InitialiseSettings.php
# - wmf-config/logging.php [THIS FILE]
#
# Included from: wmf-config/CommonSettings.php.
#

#
# The following globals from InitialiseSettings are used:
#
# - $wmgExtraLogFile: udp2log destination for 'extraLogFile' handler.
# - $wmgEnableExtraLogFile: whether to enable the above
# - $wmgMonologChannels: per-channel logging config
#   - `channel => false`: ignore all log events on this channel.
#   - `channel => level`: record all events of this level or higher to udp2log and logstash.
#     Special case: `channel => debug` will not log to logstash.
#   - `channel => [
#           'udp2log'=>level,
#           'logstash'=>level,
#           'eventbus'=>level,
#           'sample'=>rate,
#           'buffer'=>buffer
#     ]`
# - $wmgUseEventBus: Whether EventBus extension is enabled on the wiki
#
#   Default for all channels for fields not otherwise specified:
#   ```
#   [
#       'udp2log' = >'debug',
#       'logstash' = >'info',
#       'eventbus' => false,
#       'sample' => false,
#       'buffer' => false,
#   ]
#   ```
#
#   Valid levels: 'debug', 'info', 'warning', 'error', false.
#
#   Note: Sampled logs will not be sent to Logstash!
#
#   Note: Udp2log events are sent to udp://{$wmgUdp2logDest}/{$channel}.
#   Ultimately they end up in logfiles on mwlog1001.
#
# - $wmgUdp2logDest: udp2log host and port.
# - $wmgLogAuthmanagerMetrics: Controls additional authmanager logging.
#

use MediaWiki\Logger\LoggerFactory;
use Wikimedia\MWConfig\XWikimediaDebug;

// Logstash servers running syslog endpoint to collect log events.
// Use false to disable all Logstash logging
$wmgEnableLogstash = true;

function wmfApplyDebugLoggingHacks() {
	if ( getenv( 'MW_DEBUG_LOCAL' ) ) {
		// Route all log messages to a local file
		$logFile = '/tmp/wiki.log';
		$handlers = [ 'debugLogging' ];
	} elseif ( XWikimediaDebug::getInstance()->hasOption( 'log' ) ) {
		global $wmgUdp2logDest;
		// Forward all log messages to logstash for debugging.
		// See <https://wikitech.wikimedia.org/wiki/X-Wikimedia-Debug>.
		$logFile = "udp://{$wmgUdp2logDest}/XWikimediaDebug";
		$handlers = [ 'debugLogging', 'logstash-debug' ];
	} else {
		// No changes to normal logging config
		return;
	}

	global $wgDebugDumpSql;
	$wgDebugDumpSql = true;

	global $wgMWLoggerDefaultSpi;
	$wgMWLoggerDefaultSpi['args'][0]['handlers'] += [
		'debugLogging' => [
			'class'     => \MediaWiki\Logger\Monolog\LegacyHandler::class,
			'args'      => [ $logFile ],
			'formatter' => 'line',
		],
	];
	// Override all default loggers (as if setting `$wmgMonologChannels = []`)
	$wgMWLoggerDefaultSpi['args'][0]['loggers'] = [
		'@default' => [
			'handlers' => $handlers,
			'processors' => array_keys( $wgMWLoggerDefaultSpi['args'][0]['processors'] ),
		],
	];
}

function wmfGetLoggingConfig() {
	global $wmgExtraLogFile, $wmgEnableExtraLogFile, $wmgMonologChannels, $wmgUseEventBus,
		$wmgUdp2logDest, $wmgLogAuthmanagerMetrics, $wmgUseWikimediaEvents, $wmgEnableLogstash;

	// TODO: Should not be global, referenced in wikitech.php (see discussion on I4189c209b)
	global $wmgMonologProcessors;

	// T124985: The Processors listed in $monologProcessors are applied to
	// a message list order (top to bottom) since 1.41.0-wmf.30 (19b97fd575).
	//
	// The `wmfconfig` processor injects `normalized_message` which must be listed
	// *before* the psr processor since we want to retain the log placeholders for
	// log deduplication (T349086).
	$monologProcessors = $wmgMonologProcessors = [
		// Injects wiki, MediaWiki version, request id etc
		'wiki' => [
			'class' => \MediaWiki\Logger\Monolog\WikiProcessor::class,
		],
		// Additional fields injected before processing eg placeholders in log
		// messages.
		'wmfconfig' => [
			'factory' => static function () {
				return static function ( array $record ) {
					// Like Monolog\Processor\WebProcessor, but without 'unique_id' (per T253677).
					// And without 'ip' (per T114700).
					//
					// Ref <https://github.com/Seldaek/monolog/issues/1470>
					// Ref <https://github.com/Seldaek/monolog/blob/1.5.0/src/Monolog/Processor/WebProcessor.php>
					if ( isset( $_SERVER['REQUEST_URI'] ) ) {
						$record['extra'] += [
							'url' => $_SERVER['REQUEST_URI'] ?? null,
							'http_method' => $_SERVER['REQUEST_METHOD'] ?? null,
							'server' => $_SERVER['SERVER_NAME'] ?? null,
							'referrer' => $_SERVER['HTTP_REFERER'] ?? null,
						];
					}

					// T215350: add PHP version information
					$record['extra']['phpversion'] = phpversion();

					// T255627: add label for the server group the current server belongs to.
					// This is exposed by Apache configuration defined in Puppet profile::mediawiki::httpd.
					// Its value is that of the Hiera 'cluster' key in Puppet (e.g. "appserver", "parsoid", etc).
					// For pods running on Kubernetes, the servergroup is determined by the value of
					// the php.servergroup Helm setting and will be prefixed by "kube-" (e.g.
					// operations/deployment-charts:helmfile.d/services/mwdebug/values.yaml).
					//
					// This is not set on CLI (e.g. deploy, maint, snapshot).
					//
					// Ref <https://wikitech.wikimedia.org/wiki/MediaWiki_at_WMF#App_servers>
					$record['extra']['servergroup'] = $_SERVER['SERVERGROUP'] ?? 'other';

					/**
					 * Add a "normalized_message" field to log records.
					 *
					 * Field is the first 255 chars of 'message' after stripping out
					 * anchor tags which are sometimes inserted in error and warning
					 * messages by PHP. If applied before PsrLogMessageProcessor,
					 * placeholders in the message will be left unexpanded which can
					 * reduce variance of messages that expand to include per-request
					 * details such as session ids.
					 *
					 * We rely on the placeholders not being expanded to deduplicate
					 * log messages (T349086).
					 */
					$nm = $record['message'];
					if ( strpos( $nm, '<a href=' ) !== false ) {
						// Remove documentation anchor tags
						$nm = preg_replace(
							"|<a href='[^']*'>[^<]*</a>|",
							'',
							$nm
						);
					}
					// Trim to <= 255 chars
					$record['extra']['normalized_message'] = substr( $nm, 0, 255 );

					// Adds the database shard name (e.g. s1, s2, ...)
					global $wgLBFactoryConf, $wgDBname;
					$record['extra']['shard'] = $wgLBFactoryConf['sectionsByDB'][$wgDBname] ?? 's3';

					return $record;
				};
			},
		],
		'psr' => [
			'class' => \Monolog\Processor\PsrLogMessageProcessor::class,
		],
	];

	$monologHandlers = [];
	if ( $wmgEnableExtraLogFile ) {
		$monologHandlers['extraLogFile'] = [
			'class'     => \MediaWiki\Logger\Monolog\LegacyHandler::class,
			'args'      => [ $wmgExtraLogFile ],
			'formatter' => 'line',
		];
	}

	$supportedLogLevels = [ 'debug', 'info', 'warning', 'error' ];
	foreach ( $supportedLogLevels as $logLevel ) {
		$monologHandlers[ "udp2log-$logLevel" ] = [
			'class' => \MediaWiki\Logger\Monolog\LegacyHandler::class,
			'args' => [
				"udp://{$wmgUdp2logDest}/{channel}",
				false,
				$logLevel
			],
			'formatter' => 'line',
		];
	}

	if ( $wmgEnableLogstash ) {
		foreach ( $supportedLogLevels as $logLevel ) {
			$monologHandlers[ "logstash-$logLevel" ] = [
				'class'     => \MediaWiki\Logger\Monolog\SyslogHandler::class,
				'formatter' => 'cee',
				'args'      => [
					// tag
					'mediawiki',
					// host
					'127.0.0.1',
					// port
					10514,
					// facility
					LOG_USER,
					// log level threshold
					$logLevel,
				],
			];
		}
	}

	$monologFormatters = [
		'line' => [
			'class' => \MediaWiki\Logger\Monolog\LineFormatter::class,
			'args' => [
				"%datetime% [%extra.reqId%] %extra.host% %extra.wiki% %extra.mwversion% %channel% %level_name%: %message% %context% %exception%\n",
				'Y-m-d H:i:s.u',
				// allowInlineLineBreaks
				true,
				// ignoreEmptyContextAndExtra
				true,
				// includeStacktraces
				true,
			],
		],
		'cee' => [
			'class' => \MediaWiki\Logger\Monolog\CeeFormatter::class,
			'args'  => [ 'mediawiki', php_uname( 'n' ), '', '', 1 ],
		],
	];

	$monologLoggers = [];
	// Add logging channels defined in $wmgMonologChannels
	foreach ( $wmgMonologChannels as $channel => $opts ) {
		if ( $opts === false ) {
			// Log channel disabled on this wiki
			$monologLoggers[$channel] = [
				'handlers' => [],
			];
			continue;
		}

		$opts = is_array( $opts ) ? $opts : [ 'udp2log' => $opts ];

		// Defaults
		$opts += [
			'udp2log' => 'debug',
			'eventbus' => false,
			'sample' => false,
			'buffer' => false,
		];
		$opts += [
			'logstash' => ( $opts['udp2log'] !== 'debug' ) ? $opts['udp2log'] : 'info',
		];

		// Sampled logs are never passed to logstash
		if ( $opts['sample'] !== false ) {
			$opts['logstash'] = false;
		}

		$handlers = [];

		if ( $opts['udp2log'] ) {
			$handlers[] = "udp2log-{$opts['udp2log']}";
			if ( $wmgEnableExtraLogFile ) {
				// T117019: Send messages to extra handler location as well
				// This is for messages from regular traffic to testwikis.
				$handlers[] = 'extraLogFile';
			}
		}

		if ( $opts['eventbus'] && $wmgUseEventBus ) {
			$eventBusHandler = "eventbus-{$opts['eventbus']}";
			// Register handler that will only pass events of the given log level
			$monologHandlers[$eventBusHandler] ??= [
				'class' => \MediaWiki\Extension\EventBus\Adapters\Monolog\EventBusMonologHandler::class,
				'args' => [
					// EventServiceName
					'eventgate-analytics'
				]
			];
			$handlers[] = $eventBusHandler;
		}

		// Configure Logstash handler
		if ( $opts['logstash'] && $wmgEnableLogstash ) {
			$level = $opts['logstash'];
			$logstashHandler = "logstash-{$level}";
			if ( isset( $monologHandlers[ $logstashHandler ] ) ) {
				$handlers[] = $logstashHandler;
			}
		}

		if ( $opts['sample'] ) {
			$sample = $opts['sample'];
			foreach ( $handlers as $idx => $handlerName ) {
				$sampledHandler = "{$handlerName}-sampled-{$sample}";
				// Register a handler that will sample the event stream and
				// pass events on to $handlerName for storage
				$monologHandlers[$sampledHandler] ??= [
					'class' => \Monolog\Handler\SamplingHandler::class,
					'args' => [
						static function () use ( $handlerName ) {
							return LoggerFactory::getProvider()->getHandler(
								$handlerName
							);
						},
						$sample,
					],
				];
				$handlers[$idx] = $sampledHandler;
			}
		}

		if ( $opts['buffer'] ) {
			foreach ( $handlers as $idx => $handlerName ) {
				$bufferedHandler = "{$handlerName}-buffered";
				// Register a handler that will buffer the event stream and
				// pass events to the nested handler after closing the request
				$monologHandlers[$bufferedHandler] ??= [
					'class' => \MediaWiki\Logger\Monolog\BufferHandler::class,
					'args' => [
						static function () use ( $handlerName ) {
							return LoggerFactory::getProvider()->getHandler(
								$handlerName
							);
						},
					],
				];
				$handlers[$idx] = $bufferedHandler;
			}
		}

		if ( $handlers ) {
			// T118057: wrap the collection of handlers in a WhatFailureGroupHandler
			// to swallow any exceptions that might leak out otherwise
			$failureGroupHandler = 'failuregroup|' . implode( '|', $handlers );
			$monologHandlers[$failureGroupHandler] = [
				'class' => \Monolog\Handler\WhatFailureGroupHandler::class,
				'args' => [
					static function () use ( $handlers ) {
						$provider = LoggerFactory::getProvider();
						return array_map(
							[ $provider, 'getHandler' ],
							$handlers
						);
					}
				],
			];

			$monologLoggers[$channel] = [
				'handlers' => [ $failureGroupHandler ],
				'processors' => array_keys( $monologProcessors ),
			];
		}
	}

	// Ensure extra logging works even if @default channel is not configured
	if ( $wmgEnableExtraLogFile ) {
		$monologLoggers['@default'] ??= [
			'handlers' => [ 'extraLogFile' ],
			'processors' => array_keys( $monologProcessors ),
		];
	}

	if (
		$wmgLogAuthmanagerMetrics
		// T160490
		&& $wmgUseWikimediaEvents
	) {
		$monologLoggers['authevents']['handlers'][] = 'authmanager-statsd';
		$monologLoggers['captcha']['handlers'][] = 'authmanager-statsd';
		$monologHandlers['authmanager-statsd'] = [
			// defined in WikimediaEvents
			'class' => WikimediaEvents\AuthManagerStatsdHandler::class,
		];
	}

	// Used in $wgMWLoggerDefaultSpi
	return [
		'loggers' => $monologLoggers,
		'processors' => $monologProcessors,
		'handlers' => $monologHandlers,
		'formatters' => $monologFormatters,
	];
}