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 * readOnlyBySection A map of section name to read-only message.
72 * Missing or false for read/write.
76 class LBFactoryMulti
extends LBFactory
{
79 /** @var array A map of database names to section names */
80 protected $sectionsByDB;
83 * @var array A 2-d map. For each section, gives a map of server names to
86 protected $sectionLoads;
89 * @var array A server info associative array as documented for
90 * $wgDBservers. The host, hostName and load entries will be
93 protected $serverTemplate;
97 /** @var array A 3-d map giving server load ratios for each section and group */
98 protected $groupLoadsBySection = array();
100 /** @var array A 3-d map giving server load ratios by DB name */
101 protected $groupLoadsByDB = array();
103 /** @var array A map of hostname to IP address */
104 protected $hostsByName = array();
106 /** @var array A map of external storage cluster name to server load map */
107 protected $externalLoads = array();
110 * @var array A set of server info keys overriding serverTemplate for
113 protected $externalTemplateOverrides;
116 * @var array A 2-d map overriding serverTemplate and
117 * externalTemplateOverrides on a server-by-server basis. Applies to both
118 * core and external storage
120 protected $templateOverridesByServer;
122 /** @var array A 2-d map overriding the server info by external storage cluster */
123 protected $templateOverridesByCluster;
125 /** @var array An override array for all master servers */
126 protected $masterTemplateOverrides;
129 * @var array|bool A map of section name to read-only message. Missing or
130 * false for read/write
132 protected $readOnlyBySection = array();
136 /** @var array Load balancer factory configuration */
139 /** @var LoadBalancer[] */
140 protected $mainLBs = array();
142 /** @var LoadBalancer[] */
143 protected $extLBs = array();
149 protected $lastSection;
153 * @throws MWException
155 function __construct( $conf ) {
156 $this->chronProt
= new ChronologyProtector
;
158 $required = array( 'sectionsByDB', 'sectionLoads', 'serverTemplate' );
159 $optional = array( 'groupLoadsBySection', 'groupLoadsByDB', 'hostsByName',
160 'externalLoads', 'externalTemplateOverrides', 'templateOverridesByServer',
161 'templateOverridesByCluster', 'masterTemplateOverrides',
162 'readOnlyBySection' );
164 foreach ( $required as $key ) {
165 if ( !isset( $conf[$key] ) ) {
166 throw new MWException( __CLASS__
. ": $key is required in configuration" );
168 $this->$key = $conf[$key];
171 foreach ( $optional as $key ) {
172 if ( isset( $conf[$key] ) ) {
173 $this->$key = $conf[$key];
177 // Check for read-only mode
178 $section = $this->getSectionForWiki();
179 if ( !empty( $this->readOnlyBySection
[$section] ) ) {
181 $wgReadOnly = $this->readOnlyBySection
[$section];
186 * @param bool|string $wiki
189 function getSectionForWiki( $wiki = false ) {
190 if ( $this->lastWiki
=== $wiki ) {
191 return $this->lastSection
;
193 list( $dbName, ) = $this->getDBNameAndPrefix( $wiki );
194 if ( isset( $this->sectionsByDB
[$dbName] ) ) {
195 $section = $this->sectionsByDB
[$dbName];
197 $section = 'DEFAULT';
199 $this->lastSection
= $section;
200 $this->lastWiki
= $wiki;
206 * @param bool|string $wiki
207 * @return LoadBalancer
209 function newMainLB( $wiki = false ) {
210 list( $dbName, ) = $this->getDBNameAndPrefix( $wiki );
211 $section = $this->getSectionForWiki( $wiki );
212 $groupLoads = array();
213 if ( isset( $this->groupLoadsByDB
[$dbName] ) ) {
214 $groupLoads = $this->groupLoadsByDB
[$dbName];
217 if ( isset( $this->groupLoadsBySection
[$section] ) ) {
218 $groupLoads = array_merge_recursive( $groupLoads, $this->groupLoadsBySection
[$section] );
221 return $this->newLoadBalancer(
222 $this->serverTemplate
,
223 $this->sectionLoads
[$section],
229 * @param bool|string $wiki
230 * @return LoadBalancer
232 function getMainLB( $wiki = false ) {
233 $section = $this->getSectionForWiki( $wiki );
234 if ( !isset( $this->mainLBs
[$section] ) ) {
235 $lb = $this->newMainLB( $wiki, $section );
236 $lb->parentInfo( array( 'id' => "main-$section" ) );
237 $this->chronProt
->initLB( $lb );
238 $this->mainLBs
[$section] = $lb;
241 return $this->mainLBs
[$section];
245 * @param string $cluster
246 * @param bool|string $wiki
247 * @throws MWException
248 * @return LoadBalancer
250 function newExternalLB( $cluster, $wiki = false ) {
251 if ( !isset( $this->externalLoads
[$cluster] ) ) {
252 throw new MWException( __METHOD__
. ": Unknown cluster \"$cluster\"" );
254 $template = $this->serverTemplate
;
255 if ( isset( $this->externalTemplateOverrides
) ) {
256 $template = $this->externalTemplateOverrides +
$template;
258 if ( isset( $this->templateOverridesByCluster
[$cluster] ) ) {
259 $template = $this->templateOverridesByCluster
[$cluster] +
$template;
262 return $this->newLoadBalancer( $template, $this->externalLoads
[$cluster], array() );
266 * @param string $cluster External storage cluster, or false for core
267 * @param bool|string $wiki Wiki ID, or false for the current wiki
268 * @return LoadBalancer
270 function &getExternalLB( $cluster, $wiki = false ) {
271 if ( !isset( $this->extLBs
[$cluster] ) ) {
272 $this->extLBs
[$cluster] = $this->newExternalLB( $cluster, $wiki );
273 $this->extLBs
[$cluster]->parentInfo( array( 'id' => "ext-$cluster" ) );
274 $this->chronProt
->initLB( $this->extLBs
[$cluster] );
277 return $this->extLBs
[$cluster];
281 * Make a new load balancer object based on template and load array
283 * @param array $template
284 * @param array $loads
285 * @param array $groupLoads
286 * @return LoadBalancer
288 function newLoadBalancer( $template, $loads, $groupLoads ) {
289 $servers = $this->makeServerArray( $template, $loads, $groupLoads );
290 $lb = new LoadBalancer( array(
291 'servers' => $servers,
298 * Make a server array as expected by LoadBalancer::__construct, using a template and load array
300 * @param array $template
301 * @param array $loads
302 * @param array $groupLoads
305 function makeServerArray( $template, $loads, $groupLoads ) {
308 $groupLoadsByServer = $this->reindexGroupLoads( $groupLoads );
309 foreach ( $groupLoadsByServer as $server => $stuff ) {
310 if ( !isset( $loads[$server] ) ) {
314 foreach ( $loads as $serverName => $load ) {
315 $serverInfo = $template;
317 $serverInfo['master'] = true;
318 if ( isset( $this->masterTemplateOverrides
) ) {
319 $serverInfo = $this->masterTemplateOverrides +
$serverInfo;
323 if ( isset( $this->templateOverridesByServer
[$serverName] ) ) {
324 $serverInfo = $this->templateOverridesByServer
[$serverName] +
$serverInfo;
326 if ( isset( $groupLoadsByServer[$serverName] ) ) {
327 $serverInfo['groupLoads'] = $groupLoadsByServer[$serverName];
329 if ( isset( $this->hostsByName
[$serverName] ) ) {
330 $serverInfo['host'] = $this->hostsByName
[$serverName];
332 $serverInfo['host'] = $serverName;
334 $serverInfo['hostName'] = $serverName;
335 $serverInfo['load'] = $load;
336 $servers[] = $serverInfo;
343 * Take a group load array indexed by group then server, and reindex it by server then group
344 * @param array $groupLoads
347 function reindexGroupLoads( $groupLoads ) {
348 $reindexed = array();
349 foreach ( $groupLoads as $group => $loads ) {
350 foreach ( $loads as $server => $load ) {
351 $reindexed[$server][$group] = $load;
359 * Get the database name and prefix based on the wiki ID
360 * @param bool|string $wiki
363 function getDBNameAndPrefix( $wiki = false ) {
364 if ( $wiki === false ) {
365 global $wgDBname, $wgDBprefix;
367 return array( $wgDBname, $wgDBprefix );
369 return wfSplitWikiID( $wiki );
374 * Execute a function for each tracked load balancer
375 * The callback is called with the load balancer as the first parameter,
376 * and $params passed as the subsequent parameters.
377 * @param callable $callback
378 * @param array $params
380 function forEachLB( $callback, $params = array() ) {
381 foreach ( $this->mainLBs
as $lb ) {
382 call_user_func_array( $callback, array_merge( array( $lb ), $params ) );
384 foreach ( $this->extLBs
as $lb ) {
385 call_user_func_array( $callback, array_merge( array( $lb ), $params ) );
389 function shutdown() {
390 foreach ( $this->mainLBs
as $lb ) {
391 $this->chronProt
->shutdownLB( $lb );
393 foreach ( $this->extLBs
as $extLB ) {
394 $this->chronProt
->shutdownLB( $extLB );
396 $this->chronProt
->shutdown();
397 $this->commitMasterChanges();