3 * Advanced generator of database load balancing objects for wiki farms.
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
15 * You should have received a copy of the GNU General Public License along
16 * with this program; if not, write to the Free Software Foundation, Inc.,
17 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
18 * http://www.gnu.org/copyleft/gpl.html
25 * A multi-wiki, multi-master factory for Wikimedia and similar installations.
26 * Ignores the old configuration globals
29 * sectionsByDB A map of database names to section names.
31 * sectionLoads A 2-d map. For each section, gives a map of server names to
32 * load ratios. For example:
34 * 'section1' => array(
40 * serverTemplate A server info associative array as documented for $wgDBservers.
41 * The host, hostName and load entries will be overridden.
43 * groupLoadsBySection A 3-d map giving server load ratios for each section and group.
46 * 'section1' => array(
54 * groupLoadsByDB A 3-d map giving server load ratios by DB name.
56 * hostsByName A map of hostname to IP address.
58 * externalLoads A map of external storage cluster name to server load map.
60 * externalTemplateOverrides A set of server info keys overriding serverTemplate for external
63 * templateOverridesByServer A 2-d map overriding serverTemplate and
64 * externalTemplateOverrides on a server-by-server basis. Applies
65 * to both core and external storage.
67 * templateOverridesByCluster A 2-d map overriding the server info by external storage cluster.
69 * masterTemplateOverrides An override array for all master servers.
71 * loadMonitorClass Name of the LoadMonitor class to always use.
73 * readOnlyBySection A map of section name to read-only message.
74 * Missing or false for read/write.
78 class LBFactoryMulti
extends LBFactory
{
81 /** @var array A map of database names to section names */
82 private $sectionsByDB;
85 * @var array A 2-d map. For each section, gives a map of server names to
88 private $sectionLoads;
91 * @var array A server info associative array as documented for
92 * $wgDBservers. The host, hostName and load entries will be
95 private $serverTemplate;
99 /** @var array A 3-d map giving server load ratios for each section and group */
100 private $groupLoadsBySection = array();
102 /** @var array A 3-d map giving server load ratios by DB name */
103 private $groupLoadsByDB = array();
105 /** @var array A map of hostname to IP address */
106 private $hostsByName = array();
108 /** @var array A map of external storage cluster name to server load map */
109 private $externalLoads = array();
112 * @var array A set of server info keys overriding serverTemplate for
115 private $externalTemplateOverrides;
118 * @var array A 2-d map overriding serverTemplate and
119 * externalTemplateOverrides on a server-by-server basis. Applies to both
120 * core and external storage
122 private $templateOverridesByServer;
124 /** @var array A 2-d map overriding the server info by external storage cluster */
125 private $templateOverridesByCluster;
127 /** @var array An override array for all master servers */
128 private $masterTemplateOverrides;
131 * @var array|bool A map of section name to read-only message. Missing or
132 * false for read/write
134 private $readOnlyBySection = array();
138 /** @var array Load balancer factory configuration */
141 /** @var LoadBalancer[] */
142 private $mainLBs = array();
144 /** @var LoadBalancer[] */
145 private $extLBs = array();
148 private $loadMonitorClass;
154 private $lastSection;
158 * @throws MWException
160 public function __construct( array $conf ) {
161 $this->chronProt
= new ChronologyProtector
;
163 $required = array( 'sectionsByDB', 'sectionLoads', 'serverTemplate' );
164 $optional = array( 'groupLoadsBySection', 'groupLoadsByDB', 'hostsByName',
165 'externalLoads', 'externalTemplateOverrides', 'templateOverridesByServer',
166 'templateOverridesByCluster', 'masterTemplateOverrides',
167 'readOnlyBySection', 'loadMonitorClass' );
169 foreach ( $required as $key ) {
170 if ( !isset( $conf[$key] ) ) {
171 throw new MWException( __CLASS__
. ": $key is required in configuration" );
173 $this->$key = $conf[$key];
176 foreach ( $optional as $key ) {
177 if ( isset( $conf[$key] ) ) {
178 $this->$key = $conf[$key];
184 * @param bool|string $wiki
187 private function getSectionForWiki( $wiki = false ) {
188 if ( $this->lastWiki
=== $wiki ) {
189 return $this->lastSection
;
191 list( $dbName, ) = $this->getDBNameAndPrefix( $wiki );
192 if ( isset( $this->sectionsByDB
[$dbName] ) ) {
193 $section = $this->sectionsByDB
[$dbName];
195 $section = 'DEFAULT';
197 $this->lastSection
= $section;
198 $this->lastWiki
= $wiki;
204 * @param bool|string $wiki
205 * @return LoadBalancer
207 public function newMainLB( $wiki = false ) {
208 list( $dbName, ) = $this->getDBNameAndPrefix( $wiki );
209 $section = $this->getSectionForWiki( $wiki );
210 $groupLoads = array();
211 if ( isset( $this->groupLoadsByDB
[$dbName] ) ) {
212 $groupLoads = $this->groupLoadsByDB
[$dbName];
215 if ( isset( $this->groupLoadsBySection
[$section] ) ) {
216 $groupLoads = array_merge_recursive( $groupLoads, $this->groupLoadsBySection
[$section] );
219 return $this->newLoadBalancer(
220 $this->serverTemplate
,
221 $this->sectionLoads
[$section],
227 * @param bool|string $wiki
228 * @return LoadBalancer
230 public function getMainLB( $wiki = false ) {
231 $section = $this->getSectionForWiki( $wiki );
232 if ( !isset( $this->mainLBs
[$section] ) ) {
233 $lb = $this->newMainLB( $wiki );
234 $lb->parentInfo( array( 'id' => "main-$section" ) );
235 $this->chronProt
->initLB( $lb );
236 $this->mainLBs
[$section] = $lb;
239 return $this->mainLBs
[$section];
243 * @param string $cluster
244 * @param bool|string $wiki
245 * @throws MWException
246 * @return LoadBalancer
248 protected function newExternalLB( $cluster, $wiki = false ) {
249 if ( !isset( $this->externalLoads
[$cluster] ) ) {
250 throw new MWException( __METHOD__
. ": Unknown cluster \"$cluster\"" );
252 $template = $this->serverTemplate
;
253 if ( isset( $this->externalTemplateOverrides
) ) {
254 $template = $this->externalTemplateOverrides +
$template;
256 if ( isset( $this->templateOverridesByCluster
[$cluster] ) ) {
257 $template = $this->templateOverridesByCluster
[$cluster] +
$template;
260 return $this->newLoadBalancer( $template, $this->externalLoads
[$cluster], array() );
264 * @param string $cluster External storage cluster, or false for core
265 * @param bool|string $wiki Wiki ID, or false for the current wiki
266 * @return LoadBalancer
268 public function &getExternalLB( $cluster, $wiki = false ) {
269 if ( !isset( $this->extLBs
[$cluster] ) ) {
270 $this->extLBs
[$cluster] = $this->newExternalLB( $cluster, $wiki );
271 $this->extLBs
[$cluster]->parentInfo( array( 'id' => "ext-$cluster" ) );
272 $this->chronProt
->initLB( $this->extLBs
[$cluster] );
275 return $this->extLBs
[$cluster];
279 * Make a new load balancer object based on template and load array
281 * @param array $template
282 * @param array $loads
283 * @param array $groupLoads
284 * @return LoadBalancer
286 private function newLoadBalancer( $template, $loads, $groupLoads ) {
287 $servers = $this->makeServerArray( $template, $loads, $groupLoads );
288 $lb = new LoadBalancer( array(
289 'servers' => $servers,
290 'loadMonitor' => $this->loadMonitorClass
297 * Make a server array as expected by LoadBalancer::__construct, using a template and load array
299 * @param array $template
300 * @param array $loads
301 * @param array $groupLoads
304 private function makeServerArray( $template, $loads, $groupLoads ) {
307 $groupLoadsByServer = $this->reindexGroupLoads( $groupLoads );
308 foreach ( $groupLoadsByServer as $server => $stuff ) {
309 if ( !isset( $loads[$server] ) ) {
313 foreach ( $loads as $serverName => $load ) {
314 $serverInfo = $template;
316 $serverInfo['master'] = true;
317 if ( isset( $this->masterTemplateOverrides
) ) {
318 $serverInfo = $this->masterTemplateOverrides +
$serverInfo;
322 $serverInfo['slave'] = true;
324 if ( isset( $this->templateOverridesByServer
[$serverName] ) ) {
325 $serverInfo = $this->templateOverridesByServer
[$serverName] +
$serverInfo;
327 if ( isset( $groupLoadsByServer[$serverName] ) ) {
328 $serverInfo['groupLoads'] = $groupLoadsByServer[$serverName];
330 if ( isset( $this->hostsByName
[$serverName] ) ) {
331 $serverInfo['host'] = $this->hostsByName
[$serverName];
333 $serverInfo['host'] = $serverName;
335 $serverInfo['hostName'] = $serverName;
336 $serverInfo['load'] = $load;
337 $servers[] = $serverInfo;
344 * Take a group load array indexed by group then server, and reindex it by server then group
345 * @param array $groupLoads
348 private function reindexGroupLoads( $groupLoads ) {
349 $reindexed = array();
350 foreach ( $groupLoads as $group => $loads ) {
351 foreach ( $loads as $server => $load ) {
352 $reindexed[$server][$group] = $load;
360 * Get the database name and prefix based on the wiki ID
361 * @param bool|string $wiki
364 private function getDBNameAndPrefix( $wiki = false ) {
365 if ( $wiki === false ) {
366 global $wgDBname, $wgDBprefix;
368 return array( $wgDBname, $wgDBprefix );
370 return wfSplitWikiID( $wiki );
375 * Execute a function for each tracked load balancer
376 * The callback is called with the load balancer as the first parameter,
377 * and $params passed as the subsequent parameters.
378 * @param callable $callback
379 * @param array $params
381 public function forEachLB( $callback, array $params = array() ) {
382 foreach ( $this->mainLBs
as $lb ) {
383 call_user_func_array( $callback, array_merge( array( $lb ), $params ) );
385 foreach ( $this->extLBs
as $lb ) {
386 call_user_func_array( $callback, array_merge( array( $lb ), $params ) );
390 public function shutdown() {
391 foreach ( $this->mainLBs
as $lb ) {
392 $this->chronProt
->shutdownLB( $lb );
394 foreach ( $this->extLBs
as $extLB ) {
395 $this->chronProt
->shutdownLB( $extLB );
397 $this->chronProt
->shutdown();
398 $this->commitMasterChanges();