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LBFactoryMulti.php
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1 <?php
24 namespace Wikimedia\Rdbms;
25 
27 
34 class LBFactoryMulti extends LBFactory {
36  private $sectionsByDB;
37 
42  private $sectionLoads;
43 
48  private $serverTemplate;
49 
50  // Optional settings
51 
53  private $groupLoadsBySection = [];
54 
56  private $groupLoadsByDB = [];
57 
59  private $hostsByName = [];
60 
62  private $externalLoads = [];
63 
69 
76 
79 
82 
85 
90  private $readOnlyBySection = [];
91 
93  private $mainLBs = [];
94 
96  private $extLBs = [];
97 
99  private $loadMonitorClass = 'LoadMonitor';
100 
102  private $lastDomain;
103 
105  private $lastSection;
106 
163  public function __construct( array $conf ) {
164  parent::__construct( $conf );
165 
166  $required = [ 'sectionsByDB', 'sectionLoads', 'serverTemplate' ];
167  $optional = [ 'groupLoadsBySection', 'groupLoadsByDB', 'hostsByName',
168  'externalLoads', 'externalTemplateOverrides', 'templateOverridesByServer',
169  'templateOverridesByCluster', 'templateOverridesBySection', 'masterTemplateOverrides',
170  'readOnlyBySection', 'loadMonitorClass' ];
171 
172  foreach ( $required as $key ) {
173  if ( !isset( $conf[$key] ) ) {
174  throw new InvalidArgumentException( __CLASS__ . ": $key is required." );
175  }
176  $this->$key = $conf[$key];
177  }
178 
179  foreach ( $optional as $key ) {
180  if ( isset( $conf[$key] ) ) {
181  $this->$key = $conf[$key];
182  }
183  }
184  }
185 
190  private function getSectionForDomain( $domain = false ) {
191  if ( $this->lastDomain === $domain ) {
192  return $this->lastSection;
193  }
194  list( $dbName, ) = $this->getDBNameAndPrefix( $domain );
195  $section = $this->sectionsByDB[$dbName] ?? 'DEFAULT';
196  $this->lastSection = $section;
197  $this->lastDomain = $domain;
198 
199  return $section;
200  }
201 
206  public function newMainLB( $domain = false ) {
207  list( $dbName, ) = $this->getDBNameAndPrefix( $domain );
208  $section = $this->getSectionForDomain( $domain );
209  $groupLoads = $this->groupLoadsByDB[$dbName] ?? [];
210 
211  if ( isset( $this->groupLoadsBySection[$section] ) ) {
212  $groupLoads = array_merge_recursive(
213  $groupLoads, $this->groupLoadsBySection[$section] );
214  }
215 
217  // Use the LB-specific read-only reason if everything isn't already read-only
218  if ( $readOnlyReason === false && isset( $this->readOnlyBySection[$section] ) ) {
219  $readOnlyReason = $this->readOnlyBySection[$section];
220  }
221 
223  if ( isset( $this->templateOverridesBySection[$section] ) ) {
224  $template = $this->templateOverridesBySection[$section] + $template;
225  }
226 
227  return $this->newLoadBalancer(
228  $template,
229  $this->sectionLoads[$section],
230  $groupLoads,
232  );
233  }
234 
239  public function getMainLB( $domain = false ) {
240  $section = $this->getSectionForDomain( $domain );
241  if ( !isset( $this->mainLBs[$section] ) ) {
242  $this->mainLBs[$section] = $this->newMainLB( $domain );
243  }
244 
245  return $this->mainLBs[$section];
246  }
247 
248  public function newExternalLB( $cluster ) {
249  if ( !isset( $this->externalLoads[$cluster] ) ) {
250  throw new InvalidArgumentException( __METHOD__ . ": Unknown cluster \"$cluster\"" );
251  }
253  if ( $this->externalTemplateOverrides ) {
254  $template = $this->externalTemplateOverrides + $template;
255  }
256  if ( isset( $this->templateOverridesByCluster[$cluster] ) ) {
257  $template = $this->templateOverridesByCluster[$cluster] + $template;
258  }
259 
260  return $this->newLoadBalancer(
261  $template,
262  $this->externalLoads[$cluster],
263  [],
264  $this->readOnlyReason
265  );
266  }
267 
268  public function getExternalLB( $cluster ) {
269  if ( !isset( $this->extLBs[$cluster] ) ) {
270  $this->extLBs[$cluster] = $this->newExternalLB( $cluster );
271  }
272 
273  return $this->extLBs[$cluster];
274  }
275 
276  public function getAllMainLBs() {
277  $lbs = [];
278  foreach ( $this->sectionsByDB as $db => $section ) {
279  if ( !isset( $lbs[$section] ) ) {
280  $lbs[$section] = $this->getMainLB( $db );
281  }
282  }
283 
284  return $lbs;
285  }
286 
287  public function getAllExternalLBs() {
288  $lbs = [];
289  foreach ( $this->externalLoads as $cluster => $unused ) {
290  $lbs[$cluster] = $this->getExternalLB( $cluster );
291  }
292 
293  return $lbs;
294  }
295 
305  private function newLoadBalancer( $template, $loads, $groupLoads, $readOnlyReason ) {
306  $lb = new LoadBalancer( array_merge(
307  $this->baseLoadBalancerParams(),
308  [
309  'servers' => $this->makeServerArray( $template, $loads, $groupLoads ),
310  'loadMonitor' => [ 'class' => $this->loadMonitorClass ],
311  'readOnlyReason' => $readOnlyReason
312  ]
313  ) );
314  $this->initLoadBalancer( $lb );
315 
316  return $lb;
317  }
318 
327  private function makeServerArray( $template, $loads, $groupLoads ) {
328  $servers = [];
329  $master = true;
330  $groupLoadsByServer = $this->reindexGroupLoads( $groupLoads );
331  foreach ( $groupLoadsByServer as $server => $stuff ) {
332  if ( !isset( $loads[$server] ) ) {
333  $loads[$server] = 0;
334  }
335  }
336  foreach ( $loads as $serverName => $load ) {
337  $serverInfo = $template;
338  if ( $master ) {
339  $serverInfo['master'] = true;
340  if ( $this->masterTemplateOverrides ) {
341  $serverInfo = $this->masterTemplateOverrides + $serverInfo;
342  }
343  $master = false;
344  } else {
345  $serverInfo['replica'] = true;
346  }
347  if ( isset( $this->templateOverridesByServer[$serverName] ) ) {
348  $serverInfo = $this->templateOverridesByServer[$serverName] + $serverInfo;
349  }
350  if ( isset( $groupLoadsByServer[$serverName] ) ) {
351  $serverInfo['groupLoads'] = $groupLoadsByServer[$serverName];
352  }
353  $serverInfo['host'] = $this->hostsByName[$serverName] ?? $serverName;
354  $serverInfo['hostName'] = $serverName;
355  $serverInfo['load'] = $load;
356  $serverInfo += [ 'flags' => IDatabase::DBO_DEFAULT ];
357 
358  $servers[] = $serverInfo;
359  }
360 
361  return $servers;
362  }
363 
369  private function reindexGroupLoads( $groupLoads ) {
370  $reindexed = [];
371  foreach ( $groupLoads as $group => $loads ) {
372  foreach ( $loads as $server => $load ) {
373  $reindexed[$server][$group] = $load;
374  }
375  }
376 
377  return $reindexed;
378  }
379 
384  private function getDBNameAndPrefix( $domain = false ) {
385  $domain = ( $domain === false )
386  ? $this->localDomain
387  : DatabaseDomain::newFromId( $domain );
388 
389  return [ $domain->getDatabase(), $domain->getTablePrefix() ];
390  }
391 
399  public function forEachLB( $callback, array $params = [] ) {
400  foreach ( $this->mainLBs as $lb ) {
401  $callback( $lb, ...$params );
402  }
403  foreach ( $this->extLBs as $lb ) {
404  $callback( $lb, ...$params );
405  }
406  }
407 }
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forEachLB( $callback, array $params=[])
Execute a function for each tracked load balancer The callback is called with the load balancer as th...
deferred txt A few of the database updates required by various functions here can be deferred until after the result page is displayed to the user For updating the view updating the linked to tables after a etc PHP does not yet have any way to tell the server to actually return and disconnect while still running these but it might have such a feature in the future We handle these by creating a deferred update object and putting those objects on a global list
Definition: deferred.txt:11
string bool $readOnlyReason
Reason all LBs are read-only or false if not.
Definition: LBFactory.php:93
processing should stop and the error should be shown to the user * false
Definition: hooks.txt:187
reindexGroupLoads( $groupLoads)
Take a group load array indexed by group then server, and reindex it by server then group...
An interface for generating database load balancers.
Definition: LBFactory.php:39
Apache License January AND DISTRIBUTION Definitions License shall mean the terms and conditions for use
array $templateOverridesByCluster
A 2-d map overriding the server info by external storage cluster.
array $templateOverridesBySection
A 2-d map overriding the server info by section.
getExternalLB( $cluster)
Get a cached (tracked) load balancer for external storage.
A multi-database, multi-master factory for Wikimedia and similar installations.
newExternalLB( $cluster)
Create a new load balancer for external storage.
getAllExternalLBs()
Get cached (tracked) load balancers for all external database clusters.
makeServerArray( $template, $loads, $groupLoads)
Make a server array as expected by LoadBalancer::__construct, using a template and load array...
array $sectionsByDB
A map of database names to section names.
initLoadBalancer(ILoadBalancer $lb)
Definition: LBFactory.php:609
array $externalTemplateOverrides
A set of server info keys overriding serverTemplate for external storage.
array $groupLoadsByDB
A 3-d map giving server load ratios by DB name.
$params
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Definition: distributors.txt:9
usually copyright or history_copyright This message must be in HTML not wikitext if the section is included from a template $section
Definition: hooks.txt:3050
array $groupLoadsBySection
A 3-d map giving server load ratios for each section and group.
injection txt This is an overview of how MediaWiki makes use of dependency injection The design described here grew from the discussion of RFC T384 The term dependency this means that anything an object needs to operate should be injected from the the object itself should only know narrow no concrete implementation of the logic it relies on The requirement to inject everything typically results in an architecture that based on two main types of and essentially stateless service objects that use other service objects to operate on the value objects As of the beginning MediaWiki is only starting to use the DI approach Much of the code still relies on global state or direct resulting in a highly cyclical dependency which acts as the top level factory for services in MediaWiki which can be used to gain access to default instances of various services MediaWikiServices however also allows new services to be defined and default services to be redefined Services are defined or redefined by providing a callback the instantiator that will return a new instance of the service When it will create an instance of MediaWikiServices and populate it with the services defined in the files listed by thereby bootstrapping the DI framework Per $wgServiceWiringFiles lists includes ServiceWiring php
Definition: injection.txt:35
const DBO_DEFAULT
Definition: defines.php:13
this hook is for auditing only or null if authentication failed before getting that far or null if we can t even determine that When $user is not it can be in the form of< username >< more info > e g for bot passwords intended to be added to log contexts Fields it might only if the login was with a bot password it is not rendered in wiki pages or galleries in category pages allow injecting custom HTML after the section Any uses of the hook need to handle escaping $template
Definition: hooks.txt:780
array $hostsByName
A map of hostname to IP address.
array $templateOverridesByServer
A 2-d map overriding serverTemplate and externalTemplateOverrides on a server-by-server basis...
newLoadBalancer( $template, $loads, $groupLoads, $readOnlyReason)
Make a new load balancer object based on template and load array.
array $masterTemplateOverrides
An override array for all master servers.
array $externalLoads
A map of external storage cluster name to server load map.
baseLoadBalancerParams()
Base parameters to ILoadBalancer::__construct()
Definition: LBFactory.php:571
getAllMainLBs()
Get cached (tracked) load balancers for all main database clusters.
Database connection, tracking, load balancing, and transaction manager for a cluster.
array bool $readOnlyBySection
A map of section name to read-only message.
array [] $serverTemplate
Server info associative array.