getLagTimes.php

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<?php
// @codeCoverageIgnoreStart
require_once __DIR__ . '/Maintenance.php';
// @codeCoverageIgnoreEnd
 
use MediaWiki\Maintenance\Maintenance;
use Wikimedia\IPUtils;
 
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