155 lines
4.6 KiB
PHP
155 lines
4.6 KiB
PHP
<?php
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/**
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* Generator of database load balancing objects.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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* http://www.gnu.org/copyleft/gpl.html
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*
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* @file
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* @ingroup Database
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*/
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namespace Wikimedia\Rdbms;
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use InvalidArgumentException;
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/**
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* A simple single-master LBFactory that gets its configuration from the b/c globals
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*/
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class LBFactorySimple extends LBFactory {
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/** @var LoadBalancer */
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private $mainLB;
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/** @var LoadBalancer[] */
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private $extLBs = [];
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/** @var array[] Map of (server index => server config) */
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private $servers = [];
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/** @var array[] Map of (cluster => (server index => server config)) */
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private $externalClusters = [];
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/** @var string */
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private $loadMonitorClass;
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/**
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* @see LBFactory::__construct()
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* @param array $conf Parameters of LBFactory::__construct() as well as:
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* - servers : list of server configuration maps to Database::factory().
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* Additionally, the server maps should have a 'load' key, which is used to decide
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* how often clients connect to one server verses the others. A 'max lag' key should
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* also be set on server maps, indicating how stale the data can be before the load
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* balancer tries to avoid using it. The map can have 'is static' set to disable blocking
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* replication sync checks (intended for archive servers with unchanging data).
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* - externalClusters : map of cluster names to server arrays. The servers arrays have the
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* same format as "servers" above.
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*/
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public function __construct( array $conf ) {
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parent::__construct( $conf );
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$this->servers = isset( $conf['servers'] ) ? $conf['servers'] : [];
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foreach ( $this->servers as $i => $server ) {
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if ( $i == 0 ) {
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$this->servers[$i]['master'] = true;
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} else {
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$this->servers[$i]['replica'] = true;
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}
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}
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$this->externalClusters = isset( $conf['externalClusters'] )
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? $conf['externalClusters']
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: [];
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$this->loadMonitorClass = isset( $conf['loadMonitorClass'] )
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? $conf['loadMonitorClass']
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: 'LoadMonitor';
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}
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/**
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* @param bool|string $domain
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* @return LoadBalancer
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*/
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public function newMainLB( $domain = false ) {
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return $this->newLoadBalancer( $this->servers );
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}
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/**
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* @param bool|string $domain
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* @return LoadBalancer
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*/
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public function getMainLB( $domain = false ) {
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if ( !isset( $this->mainLB ) ) {
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$this->mainLB = $this->newMainLB( $domain );
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}
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return $this->mainLB;
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}
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public function newExternalLB( $cluster ) {
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if ( !isset( $this->externalClusters[$cluster] ) ) {
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throw new InvalidArgumentException( __METHOD__ . ": Unknown cluster \"$cluster\"." );
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}
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return $this->newLoadBalancer( $this->externalClusters[$cluster] );
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}
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public function getExternalLB( $cluster ) {
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if ( !isset( $this->extLBs[$cluster] ) ) {
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$this->extLBs[$cluster] = $this->newExternalLB( $cluster );
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}
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return $this->extLBs[$cluster];
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}
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public function getAllMainLBs() {
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return [ 'DEFAULT' => $this->getMainLB() ];
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}
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public function getAllExternalLBs() {
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$lbs = [];
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foreach ( $this->externalClusters as $cluster => $unused ) {
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$lbs[$cluster] = $this->getExternalLB( $cluster );
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}
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return $lbs;
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}
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private function newLoadBalancer( array $servers ) {
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$lb = new LoadBalancer( array_merge(
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$this->baseLoadBalancerParams(),
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[
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'servers' => $servers,
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'loadMonitor' => [ 'class' => $this->loadMonitorClass ],
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]
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) );
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$this->initLoadBalancer( $lb );
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return $lb;
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}
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/**
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* Execute a function for each tracked load balancer
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* The callback is called with the load balancer as the first parameter,
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* and $params passed as the subsequent parameters.
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*
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* @param callable $callback
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* @param array $params
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*/
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public function forEachLB( $callback, array $params = [] ) {
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if ( isset( $this->mainLB ) ) {
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call_user_func_array( $callback, array_merge( [ $this->mainLB ], $params ) );
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}
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foreach ( $this->extLBs as $lb ) {
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call_user_func_array( $callback, array_merge( [ $lb ], $params ) );
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}
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}
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}
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