MediaWiki 1.30.2

[autoinstallsdev/mediawiki.git] / includes / libs / rdbms / lbfactory / LBFactorySimple.php

diff --git a/includes/libs/rdbms/lbfactory/LBFactorySimple.php b/includes/libs/rdbms/lbfactory/LBFactorySimple.php
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+<?php
+/**
+ * Generator of database load balancing objects.
+ *
+ * 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 Database
+ */
+
+namespace Wikimedia\Rdbms;
+
+use InvalidArgumentException;
+
+/**
+ * A simple single-master LBFactory that gets its configuration from the b/c globals
+ */
+class LBFactorySimple extends LBFactory {
+       /** @var LoadBalancer */
+       private $mainLB;
+       /** @var LoadBalancer[] */
+       private $extLBs = [];
+
+       /** @var array[] Map of (server index => server config) */
+       private $servers = [];
+       /** @var array[] Map of (cluster => (server index => server config)) */
+       private $externalClusters = [];
+
+       /** @var string */
+       private $loadMonitorClass;
+
+       /**
+        * @see LBFactory::__construct()
+        * @param array $conf Parameters of LBFactory::__construct() as well as:
+        *   - servers : list of server configuration maps to Database::factory().
+        *      Additionally, the server maps should have a 'load' key, which is used to decide
+        *      how often clients connect to one server verses the others. A 'max lag' key should
+        *      also be set on server maps, indicating how stale the data can be before the load
+        *      balancer tries to avoid using it. The map can have 'is static' set to disable blocking
+        *      replication sync checks (intended for archive servers with unchanging data).
+        *   - externalClusters : map of cluster names to server arrays. The servers arrays have the
+        *      same format as "servers" above.
+        */
+       public function __construct( array $conf ) {
+               parent::__construct( $conf );
+
+               $this->servers = isset( $conf['servers'] ) ? $conf['servers'] : [];
+               foreach ( $this->servers as $i => $server ) {
+                       if ( $i == 0 ) {
+                               $this->servers[$i]['master'] = true;
+                       } else {
+                               $this->servers[$i]['replica'] = true;
+                       }
+               }
+
+               $this->externalClusters = isset( $conf['externalClusters'] )
+                       ? $conf['externalClusters']
+                       : [];
+               $this->loadMonitorClass = isset( $conf['loadMonitorClass'] )
+                       ? $conf['loadMonitorClass']
+                       : 'LoadMonitor';
+       }
+
+       /**
+        * @param bool|string $domain
+        * @return LoadBalancer
+        */
+       public function newMainLB( $domain = false ) {
+               return $this->newLoadBalancer( $this->servers );
+       }
+
+       /**
+        * @param bool|string $domain
+        * @return LoadBalancer
+        */
+       public function getMainLB( $domain = false ) {
+               if ( !isset( $this->mainLB ) ) {
+                       $this->mainLB = $this->newMainLB( $domain );
+               }
+
+               return $this->mainLB;
+       }
+
+       public function newExternalLB( $cluster ) {
+               if ( !isset( $this->externalClusters[$cluster] ) ) {
+                       throw new InvalidArgumentException( __METHOD__ . ": Unknown cluster \"$cluster\"." );
+               }
+
+               return $this->newLoadBalancer( $this->externalClusters[$cluster] );
+       }
+
+       public function getExternalLB( $cluster ) {
+               if ( !isset( $this->extLBs[$cluster] ) ) {
+                       $this->extLBs[$cluster] = $this->newExternalLB( $cluster );
+               }
+
+               return $this->extLBs[$cluster];
+       }
+
+       public function getAllMainLBs() {
+               return [ 'DEFAULT' => $this->getMainLB() ];
+       }
+
+       public function getAllExternalLBs() {
+               $lbs = [];
+               foreach ( $this->externalClusters as $cluster => $unused ) {
+                       $lbs[$cluster] = $this->getExternalLB( $cluster );
+               }
+
+               return $lbs;
+       }
+
+       private function newLoadBalancer( array $servers ) {
+               $lb = new LoadBalancer( array_merge(
+                       $this->baseLoadBalancerParams(),
+                       [
+                               'servers' => $servers,
+                               'loadMonitor' => [ 'class' => $this->loadMonitorClass ],
+                       ]
+               ) );
+               $this->initLoadBalancer( $lb );
+
+               return $lb;
+       }
+
+       /**
+        * Execute a function for each tracked load balancer
+        * The callback is called with the load balancer as the first parameter,
+        * and $params passed as the subsequent parameters.
+        *
+        * @param callable $callback
+        * @param array $params
+        */
+       public function forEachLB( $callback, array $params = [] ) {
+               if ( isset( $this->mainLB ) ) {
+                       call_user_func_array( $callback, array_merge( [ $this->mainLB ], $params ) );
+               }
+               foreach ( $this->extLBs as $lb ) {
+                       call_user_func_array( $callback, array_merge( [ $lb ], $params ) );
+               }
+       }
+}