includes/libs/rdbms/loadmonitor/ILoadMonitor.php

   1 <?php
   2 /**
   3  * This program is free software; you can redistribute it and/or modify
   4  * it under the terms of the GNU General Public License as published by
   5  * the Free Software Foundation; either version 2 of the License, or
   6  * (at your option) any later version.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along
  14  * with this program; if not, write to the Free Software Foundation, Inc.,
  15  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  16  * http://www.gnu.org/copyleft/gpl.html
  17  *
  18  * @file
  19  */
  20 namespace Wikimedia\Rdbms;
  21
  22 use Psr\Log\LoggerAwareInterface;
  23 use Wikimedia\ObjectCache\BagOStuff;
  24 use Wikimedia\ObjectCache\WANObjectCache;
  25 use Wikimedia\Stats\StatsdAwareInterface;
  26
  27 /**
  28  * Database load monitoring interface
  29  *
  30  * @internal This class should not be called outside of LoadBalancer
  31  * @ingroup Database
  32  */
  33 interface ILoadMonitor extends LoggerAwareInterface, StatsdAwareInterface {
  34         public const STATE_UP = 'up';
  35         public const STATE_CONN_COUNT = 'conn_count';
  36         public const STATE_AS_OF = 'time';
  37
  38         /**
  39          * Construct a new LoadMonitor with a given LoadBalancer parent
  40          *
  41          * @param ILoadBalancer $lb LoadBalancer this instance serves
  42          * @param BagOStuff $sCache Local server memory cache
  43          * @param WANObjectCache $wCache Local cluster memory cache
  44          * @param array $options Additional parameters include:
  45          *   - maxConnCount: maximum number of connections before circuit breaking to kick in [default: infinity]
  46          */
  47         public function __construct( ILoadBalancer $lb, BagOStuff $sCache, WANObjectCache $wCache, $options );
  48
  49         /**
  50          * Perform load ratio adjustment before deciding which server to use
  51          *
  52          * @param array<int,int|float> &$weightByServer Map of (server index => weight)
  53          */
  54         public function scaleLoads( array &$weightByServer );
  55 }