PoolCounterConnectionManager.php

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<?php
namespace MediaWiki\PoolCounter;
 
use InvalidArgumentException;
use MediaWiki\Status\Status;
use Wikimedia\IPUtils;
 
class PoolCounterConnectionManager {
    public $hostNames;
    public $conns = [];
    public $refCounts = [];
    public $timeout;
    public $connect_timeout;
 
    public $host;
 
    public $port;
 
    public function __construct( $conf ) {
        if ( !count( $conf['servers'] ) ) {
            throw new InvalidArgumentException( __METHOD__ . ': no servers configured' );
        }
        $this->hostNames = $conf['servers'];
        $this->timeout = $conf['timeout'] ?? 0.1;
        $this->connect_timeout = $conf['connect_timeout'] ?? 0;
    }
 
    public function get( $key ) {
        $hashes = [];
        foreach ( $this->hostNames as $hostName ) {
            $hashes[$hostName] = md5( $hostName . $key );
        }
        asort( $hashes );
        $errno = 0;
        $errstr = '';
        $hostName = '';
        $conn = null;
        foreach ( $hashes as $hostName => $hash ) {
            if ( isset( $this->conns[$hostName] ) ) {
                $this->refCounts[$hostName]++;
                return Status::newGood(
                    [ 'conn' => $this->conns[$hostName], 'hostName' => $hostName ] );
            }
            $parts = IPUtils::splitHostAndPort( $hostName );
            if ( $parts === false ) {
                $errstr = '\'servers\' config incorrectly configured.';
                return Status::newFatal( 'poolcounter-connection-error', $errstr, $hostName );
            }
            // IPV6 addresses need to be in brackets otherwise it fails.
            $this->host = IPUtils::isValidIPv6( $parts[0] ) ? '[' . $parts[0] . ']' : $parts[0];
            $this->port = $parts[1] ?: 7531;
            // phpcs:ignore Generic.PHP.NoSilencedErrors.Discouraged
            $conn = @$this->open( $this->host, $this->port, $errno, $errstr );
            if ( $conn ) {
                break;
            }
        }
        if ( !$conn ) {
            return Status::newFatal( 'poolcounter-connection-error', $errstr, $hostName );
        }
        // TODO: Inject PSR Logger from ServiceWiring
        wfDebug( "Connected to pool counter server: $hostName\n" );
        $this->conns[$hostName] = $conn;
        $this->refCounts[$hostName] = 1;
        return Status::newGood( [ 'conn' => $conn, 'hostName' => $hostName ] );
    }
 
    private function open( $host, $port, &$errno, &$errstr ) {
        // If connect_timeout is set, we try to open the socket twice.
        // You usually want to set the connection timeout to a very
        // small value so that in case of failure of a server the
        // connection to poolcounter is not a SPOF.
        if ( $this->connect_timeout > 0 ) {
            $tries = 2;
            $timeout = $this->connect_timeout;
        } else {
            $tries = 1;
            $timeout = $this->timeout;
        }
 
        $fp = null;
        while ( true ) {
            $fp = fsockopen( $host, $port, $errno, $errstr, $timeout );
            if ( $fp !== false || --$tries < 1 ) {
                break;
            }
            usleep( 1000 );
        }
 
        return $fp;
    }
 
    public function close( $conn ) {
        foreach ( $this->conns as $hostName => $otherConn ) {
            if ( $conn === $otherConn ) {
                if ( $this->refCounts[$hostName] ) {
                    $this->refCounts[$hostName]--;
                }
                if ( !$this->refCounts[$hostName] ) {
                    fclose( $conn );
                    unset( $this->conns[$hostName] );
                }
            }
        }
    }
}