wikimedia/mediawiki-core

<?php
/**
 * Display replication lag times.
 *
 * 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
 * @ingroup Maintenance
 */

// @codeCoverageIgnoreStart
require_once __DIR__ . '/Maintenance.php';
// @codeCoverageIgnoreEnd

use Wikimedia\IPUtils;

/**
 * Maintenance script that displays replication lag times.
 *
 * @ingroup Maintenance
 */
class GetLagTimes extends Maintenance {
    public function __construct() {
        parent::__construct();
        $this->addDescription( 'Dump replication lag times' );
        $this->addOption( 'report', "Report the lag values to StatsD" );
    }

    public function execute() {
        $services = $this->getServiceContainer();
        $lbFactory = $services->getDBLoadBalancerFactory();
        $stats = $services->getStatsFactory();
        $lbsByType = [
            'main' => $lbFactory->getAllMainLBs(),
            'external' => $lbFactory->getAllExternalLBs()
        ];

        foreach ( $lbsByType as $type => $lbs ) {
            foreach ( $lbs as $cluster => $lb ) {
                if ( $lb->getServerCount() <= 1 ) {
                    continue;
                }
                $lags = $lb->getLagTimes();
                foreach ( $lags as $serverIndex => $lag ) {
                    $host = $lb->getServerName( $serverIndex );
                    if ( IPUtils::isValid( $host ) ) {
                        $ip = $host;
                        $host = gethostbyaddr( $host );
                    } else {
                        $ip = gethostbyname( $host );
                    }

                    if ( $lag === false ) {
                        $stars = 'replication stopped or errored';
                    } else {
                        $starLen = min( intval( $lag ), 40 );
                        $stars = str_repeat( '*', $starLen );
                    }
                    $this->output( sprintf( "%10s %20s %3d %s\n", $ip, $host, $lag, $stars ) );

                    if ( $this->hasOption( 'report' ) ) {
                        $group = ( $type === 'external' ) ? 'external' : $cluster;

                        // $lag is the lag duration in seconds
                        // emit milliseconds for backwards-compatibility
                        $stats->getGauge( 'loadbalancer_lag_milliseconds' )
                            ->setLabel( 'group', $group )
                            ->setLabel( 'host', $host )
                            ->copyToStatsdAt( "loadbalancer.lag.$group.$host" )
                            ->set( (int)( $lag * 1e3 ) );

                        // emit seconds also to align with Prometheus' recommendations
                        $stats->getGauge( 'loadbalancer_lag_seconds' )
                            ->setLabel( 'group', $group )
                            ->setLabel( 'host', $host )
                            ->set( (int)$lag );
                    }
                }
            }
        }
    }
}

// @codeCoverageIgnoreStart
$maintClass = GetLagTimes::class;
require_once RUN_MAINTENANCE_IF_MAIN;
// @codeCoverageIgnoreEnd