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MemcLockManager.php
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1 <?php
24 
41  protected $lockTypeMap = [
42  self::LOCK_SH => self::LOCK_SH,
43  self::LOCK_UW => self::LOCK_SH,
44  self::LOCK_EX => self::LOCK_EX
45  ];
46 
48  protected $cacheServers = [];
50  protected $statusCache;
51 
64  public function __construct( array $config ) {
65  parent::__construct( $config );
66 
67  // Sanitize srvsByBucket config to prevent PHP errors
68  $this->srvsByBucket = array_filter( $config['srvsByBucket'], 'is_array' );
69  $this->srvsByBucket = array_values( $this->srvsByBucket ); // consecutive
70 
71  $memcConfig = $config['memcConfig'] ?? [];
72  $memcConfig += [ 'class' => MemcachedPhpBagOStuff::class ]; // default
73 
74  $class = $memcConfig['class'];
75  if ( !is_subclass_of( $class, MemcachedBagOStuff::class ) ) {
76  throw new InvalidArgumentException( "$class is not of type MemcachedBagOStuff." );
77  }
78 
79  foreach ( $config['lockServers'] as $name => $address ) {
80  $params = [ 'servers' => [ $address ] ] + $memcConfig;
81  $this->cacheServers[$name] = new $class( $params );
82  }
83 
84  $this->statusCache = new MapCacheLRU( 100 );
85  }
86 
87  protected function getLocksOnServer( $lockSrv, array $pathsByType ) {
89 
90  $memc = $this->getCache( $lockSrv );
91  // List of affected paths
92  $paths = array_merge( ...array_values( $pathsByType ) );
93  $paths = array_unique( $paths );
94  // List of affected lock record keys
95  $keys = array_map( [ $this, 'recordKeyForPath' ], $paths );
96 
97  // Lock all of the active lock record keys...
98  if ( !$this->acquireMutexes( $memc, $keys ) ) {
99  foreach ( $paths as $path ) {
100  $status->fatal( 'lockmanager-fail-acquirelock', $path );
101  }
102 
103  return $status;
104  }
105 
106  // Fetch all the existing lock records...
107  $lockRecords = $memc->getMulti( $keys );
108 
109  $now = time();
110  // Check if the requested locks conflict with existing ones...
111  foreach ( $pathsByType as $type => $paths ) {
112  foreach ( $paths as $path ) {
113  $locksKey = $this->recordKeyForPath( $path );
114  $locksHeld = isset( $lockRecords[$locksKey] )
115  ? self::sanitizeLockArray( $lockRecords[$locksKey] )
116  : self::newLockArray(); // init
117  foreach ( $locksHeld[self::LOCK_EX] as $session => $expiry ) {
118  if ( $expiry < $now ) { // stale?
119  unset( $locksHeld[self::LOCK_EX][$session] );
120  } elseif ( $session !== $this->session ) {
121  $status->fatal( 'lockmanager-fail-acquirelock', $path );
122  }
123  }
124  if ( $type === self::LOCK_EX ) {
125  foreach ( $locksHeld[self::LOCK_SH] as $session => $expiry ) {
126  if ( $expiry < $now ) { // stale?
127  unset( $locksHeld[self::LOCK_SH][$session] );
128  } elseif ( $session !== $this->session ) {
129  $status->fatal( 'lockmanager-fail-acquirelock', $path );
130  }
131  }
132  }
133  if ( $status->isOK() ) {
134  // Register the session in the lock record array
136  // We will update this record if none of the other locks conflict
137  $lockRecords[$locksKey] = $locksHeld;
138  }
139  }
140  }
141 
142  // If there were no lock conflicts, update all the lock records...
143  if ( $status->isOK() ) {
144  foreach ( $paths as $path ) {
145  $locksKey = $this->recordKeyForPath( $path );
146  $locksHeld = $lockRecords[$locksKey];
147  $ok = $memc->set( $locksKey, $locksHeld, self::MAX_LOCK_TTL );
148  if ( !$ok ) {
149  $status->fatal( 'lockmanager-fail-acquirelock', $path );
150  } else {
151  $this->logger->debug( __METHOD__ . ": acquired lock on key $locksKey.\n" );
152  }
153  }
154  }
155 
156  // Unlock all of the active lock record keys...
157  $this->releaseMutexes( $memc, $keys );
158 
159  return $status;
160  }
161 
162  protected function freeLocksOnServer( $lockSrv, array $pathsByType ) {
164 
165  $memc = $this->getCache( $lockSrv );
166  // List of affected paths
167  $paths = array_merge( ...array_values( $pathsByType ) );
168  $paths = array_unique( $paths );
169  // List of affected lock record keys
170  $keys = array_map( [ $this, 'recordKeyForPath' ], $paths );
171 
172  // Lock all of the active lock record keys...
173  if ( !$this->acquireMutexes( $memc, $keys ) ) {
174  foreach ( $paths as $path ) {
175  $status->fatal( 'lockmanager-fail-releaselock', $path );
176  }
177 
178  return $status;
179  }
180 
181  // Fetch all the existing lock records...
182  $lockRecords = $memc->getMulti( $keys );
183 
184  // Remove the requested locks from all records...
185  foreach ( $pathsByType as $type => $paths ) {
186  foreach ( $paths as $path ) {
187  $locksKey = $this->recordKeyForPath( $path ); // lock record
188  if ( !isset( $lockRecords[$locksKey] ) ) {
189  $status->warning( 'lockmanager-fail-releaselock', $path );
190  continue; // nothing to do
191  }
192  $locksHeld = $this->sanitizeLockArray( $lockRecords[$locksKey] );
193  if ( isset( $locksHeld[$type][$this->session] ) ) {
194  unset( $locksHeld[$type][$this->session] ); // unregister this session
195  $lockRecords[$locksKey] = $locksHeld;
196  } else {
197  $status->warning( 'lockmanager-fail-releaselock', $path );
198  }
199  }
200  }
201 
202  // Persist the new lock record values...
203  foreach ( $paths as $path ) {
204  $locksKey = $this->recordKeyForPath( $path );
205  if ( !isset( $lockRecords[$locksKey] ) ) {
206  continue; // nothing to do
207  }
208  $locksHeld = $lockRecords[$locksKey];
209  if ( $locksHeld === $this->newLockArray() ) {
210  $ok = $memc->delete( $locksKey );
211  } else {
212  $ok = $memc->set( $locksKey, $locksHeld, self::MAX_LOCK_TTL );
213  }
214  if ( $ok ) {
215  $this->logger->debug( __METHOD__ . ": released lock on key $locksKey.\n" );
216  } else {
217  $status->fatal( 'lockmanager-fail-releaselock', $path );
218  }
219  }
220 
221  // Unlock all of the active lock record keys...
222  $this->releaseMutexes( $memc, $keys );
223 
224  return $status;
225  }
226 
231  protected function releaseAllLocks() {
232  return StatusValue::newGood(); // not supported
233  }
234 
240  protected function isServerUp( $lockSrv ) {
241  return (bool)$this->getCache( $lockSrv );
242  }
243 
250  protected function getCache( $lockSrv ) {
251  if ( !isset( $this->cacheServers[$lockSrv] ) ) {
252  throw new InvalidArgumentException( "Invalid cache server '$lockSrv'." );
253  }
254 
255  $online = $this->statusCache->get( "online:$lockSrv", 30 );
256  if ( $online === null ) {
257  $online = $this->cacheServers[$lockSrv]->set( __CLASS__ . ':ping', 1, 1 );
258  if ( !$online ) { // server down?
259  $this->logger->warning( __METHOD__ . ": Could not contact $lockSrv." );
260  }
261  $this->statusCache->set( "online:$lockSrv", (int)$online );
262  }
263 
264  return $online ? $this->cacheServers[$lockSrv] : null;
265  }
266 
271  protected function recordKeyForPath( $path ) {
272  return implode( ':', [ __CLASS__, 'locks', $this->sha1Base36Absolute( $path ) ] );
273  }
274 
278  protected function newLockArray() {
279  return [ self::LOCK_SH => [], self::LOCK_EX => [] ];
280  }
281 
286  protected function sanitizeLockArray( $a ) {
287  if ( is_array( $a ) && isset( $a[self::LOCK_EX] ) && isset( $a[self::LOCK_SH] ) ) {
288  return $a;
289  }
290 
291  $this->logger->error( __METHOD__ . ": reset invalid lock array." );
292 
293  return $this->newLockArray();
294  }
295 
301  protected function acquireMutexes( MemcachedBagOStuff $memc, array $keys ) {
302  $lockedKeys = [];
303 
304  // Acquire the keys in lexicographical order, to avoid deadlock problems.
305  // If P1 is waiting to acquire a key P2 has, P2 can't also be waiting for a key P1 has.
306  sort( $keys );
307 
308  // Try to quickly loop to acquire the keys, but back off after a few rounds.
309  // This reduces memcached spam, especially in the rare case where a server acquires
310  // some lock keys and dies without releasing them. Lock keys expire after a few minutes.
311  $loop = new WaitConditionLoop(
312  function () use ( $memc, $keys, &$lockedKeys ) {
313  foreach ( array_diff( $keys, $lockedKeys ) as $key ) {
314  if ( $memc->add( "$key:mutex", 1, 180 ) ) { // lock record
315  $lockedKeys[] = $key;
316  }
317  }
318 
319  return array_diff( $keys, $lockedKeys )
320  ? WaitConditionLoop::CONDITION_CONTINUE
321  : true;
322  },
323  3.0 // timeout
324  );
325  $loop->invoke();
326 
327  if ( count( $lockedKeys ) != count( $keys ) ) {
328  $this->releaseMutexes( $memc, $lockedKeys ); // failed; release what was locked
329  return false;
330  }
331 
332  return true;
333  }
334 
339  protected function releaseMutexes( MemcachedBagOStuff $memc, array $keys ) {
340  foreach ( $keys as $key ) {
341  $memc->delete( "$key:mutex" );
342  }
343  }
344 
348  function __destruct() {
349  while ( count( $this->locksHeld ) ) {
350  foreach ( $this->locksHeld as $path => $locks ) {
351  $this->doUnlock( [ $path ], self::LOCK_EX );
352  $this->doUnlock( [ $path ], self::LOCK_SH );
353  }
354  }
355  }
356 }
The wiki should then use memcached to cache various data To use multiple just add more items to the array To increase the weight of a make its entry a array("192.168.0.1:11211", 2))
Apache License January AND DISTRIBUTION Definitions License shall mean the terms and conditions for use
delete( $key, $flags=0)
__construct(array $config)
Construct a new instance from configuration.
array $lockTypeMap
Mapping of lock types to the type actually used.
MapCacheLRU $statusCache
Server status cache.
string $session
Random 32-char hex number.
Definition: LockManager.php:64
Status::newGood()` to allow deletion, and then `return false` from the hook function. Ensure you consume the 'ChangeTagAfterDelete' hook to carry out custom deletion actions. $tag:name of the tag $user:user initiating the action & $status:Status object. See above. 'ChangeTagsListActive':Allows you to nominate which of the tags your extension uses are in active use. & $tags:list of all active tags. Append to this array. 'ChangeTagsAfterUpdateTags':Called after tags have been updated with the ChangeTags::updateTags function. Params:$addedTags:tags effectively added in the update $removedTags:tags effectively removed in the update $prevTags:tags that were present prior to the update $rc_id:recentchanges table id $rev_id:revision table id $log_id:logging table id $params:tag params $rc:RecentChange being tagged when the tagging accompanies the action, or null $user:User who performed the tagging when the tagging is subsequent to the action, or null 'ChangeTagsAllowedAdd':Called when checking if a user can add tags to a change. & $allowedTags:List of all the tags the user is allowed to add. Any tags the user wants to add( $addTags) that are not in this array will cause it to fail. You may add or remove tags to this array as required. $addTags:List of tags user intends to add. $user:User who is adding the tags. 'ChangeUserGroups':Called before user groups are changed. $performer:The User who will perform the change $user:The User whose groups will be changed & $add:The groups that will be added & $remove:The groups that will be removed 'Collation::factory':Called if $wgCategoryCollation is an unknown collation. $collationName:Name of the collation in question & $collationObject:Null. Replace with a subclass of the Collation class that implements the collation given in $collationName. 'ConfirmEmailComplete':Called after a user 's email has been confirmed successfully. $user:user(object) whose email is being confirmed 'ContentAlterParserOutput':Modify parser output for a given content object. Called by Content::getParserOutput after parsing has finished. Can be used for changes that depend on the result of the parsing but have to be done before LinksUpdate is called(such as adding tracking categories based on the rendered HTML). $content:The Content to render $title:Title of the page, as context $parserOutput:ParserOutput to manipulate 'ContentGetParserOutput':Customize parser output for a given content object, called by AbstractContent::getParserOutput. May be used to override the normal model-specific rendering of page content. $content:The Content to render $title:Title of the page, as context $revId:The revision ID, as context $options:ParserOptions for rendering. To avoid confusing the parser cache, the output can only depend on parameters provided to this hook function, not on global state. $generateHtml:boolean, indicating whether full HTML should be generated. If false, generation of HTML may be skipped, but other information should still be present in the ParserOutput object. & $output:ParserOutput, to manipulate or replace 'ContentHandlerDefaultModelFor':Called when the default content model is determined for a given title. May be used to assign a different model for that title. $title:the Title in question & $model:the model name. Use with CONTENT_MODEL_XXX constants. 'ContentHandlerForModelID':Called when a ContentHandler is requested for a given content model name, but no entry for that model exists in $wgContentHandlers. Note:if your extension implements additional models via this hook, please use GetContentModels hook to make them known to core. $modeName:the requested content model name & $handler:set this to a ContentHandler object, if desired. 'ContentModelCanBeUsedOn':Called to determine whether that content model can be used on a given page. This is especially useful to prevent some content models to be used in some special location. $contentModel:ID of the content model in question $title:the Title in question. & $ok:Output parameter, whether it is OK to use $contentModel on $title. Handler functions that modify $ok should generally return false to prevent further hooks from further modifying $ok. 'ContribsPager::getQueryInfo':Before the contributions query is about to run & $pager:Pager object for contributions & $queryInfo:The query for the contribs Pager 'ContribsPager::reallyDoQuery':Called before really executing the query for My Contributions & $data:an array of results of all contribs queries $pager:The ContribsPager object hooked into $offset:Index offset, inclusive $limit:Exact query limit $descending:Query direction, false for ascending, true for descending 'ContributionsLineEnding':Called before a contributions HTML line is finished $page:SpecialPage object for contributions & $ret:the HTML line $row:the DB row for this line & $classes:the classes to add to the surrounding< li > & $attribs:associative array of other HTML attributes for the< li > element. Currently only data attributes reserved to MediaWiki are allowed(see Sanitizer::isReservedDataAttribute). 'ContributionsToolLinks':Change tool links above Special:Contributions $id:User identifier $title:User page title & $tools:Array of tool links $specialPage:SpecialPage instance for context and services. Can be either SpecialContributions or DeletedContributionsPage. Extensions should type hint against a generic SpecialPage though. 'ConvertContent':Called by AbstractContent::convert when a conversion to another content model is requested. Handler functions that modify $result should generally return false to disable further attempts at conversion. $content:The Content object to be converted. $toModel:The ID of the content model to convert to. $lossy:boolean indicating whether lossy conversion is allowed. & $result:Output parameter, in case the handler function wants to provide a converted Content object. Note that $result->getContentModel() must return $toModel. 'ContentSecurityPolicyDefaultSource':Modify the allowed CSP load sources. This affects all directives except for the script directive. If you want to add a script source, see ContentSecurityPolicyScriptSource hook. & $defaultSrc:Array of Content-Security-Policy allowed sources $policyConfig:Current configuration for the Content-Security-Policy header $mode:ContentSecurityPolicy::REPORT_ONLY_MODE or ContentSecurityPolicy::FULL_MODE depending on type of header 'ContentSecurityPolicyDirectives':Modify the content security policy directives. Use this only if ContentSecurityPolicyDefaultSource and ContentSecurityPolicyScriptSource do not meet your needs. & $directives:Array of CSP directives $policyConfig:Current configuration for the CSP header $mode:ContentSecurityPolicy::REPORT_ONLY_MODE or ContentSecurityPolicy::FULL_MODE depending on type of header 'ContentSecurityPolicyScriptSource':Modify the allowed CSP script sources. Note that you also have to use ContentSecurityPolicyDefaultSource if you want non-script sources to be loaded from whatever you add. & $scriptSrc:Array of CSP directives $policyConfig:Current configuration for the CSP header $mode:ContentSecurityPolicy::REPORT_ONLY_MODE or ContentSecurityPolicy::FULL_MODE depending on type of header 'CustomEditor':When invoking the page editor Return true to allow the normal editor to be used, or false if implementing a custom editor, e.g. for a special namespace, etc. $article:Article being edited $user:User performing the edit 'DeletedContribsPager::reallyDoQuery':Called before really executing the query for Special:DeletedContributions Similar to ContribsPager::reallyDoQuery & $data:an array of results of all contribs queries $pager:The DeletedContribsPager object hooked into $offset:Index offset, inclusive $limit:Exact query limit $descending:Query direction, false for ascending, true for descending 'DeletedContributionsLineEnding':Called before a DeletedContributions HTML line is finished. Similar to ContributionsLineEnding $page:SpecialPage object for DeletedContributions & $ret:the HTML line $row:the DB row for this line & $classes:the classes to add to the surrounding< li > & $attribs:associative array of other HTML attributes for the< li > element. Currently only data attributes reserved to MediaWiki are allowed(see Sanitizer::isReservedDataAttribute). 'DeleteUnknownPreferences':Called by the cleanupPreferences.php maintenance script to build a WHERE clause with which to delete preferences that are not known about. This hook is used by extensions that have dynamically-named preferences that should not be deleted in the usual cleanup process. For example, the Gadgets extension creates preferences prefixed with 'gadget-', and so anything with that prefix is excluded from the deletion. &where:An array that will be passed as the $cond parameter to IDatabase::select() to determine what will be deleted from the user_properties table. $db:The IDatabase object, useful for accessing $db->buildLike() etc. 'DifferenceEngineAfterLoadNewText':called in DifferenceEngine::loadNewText() after the new revision 's content has been loaded into the class member variable $differenceEngine->mNewContent but before returning true from this function. $differenceEngine:DifferenceEngine object 'DifferenceEngineLoadTextAfterNewContentIsLoaded':called in DifferenceEngine::loadText() after the new revision 's content has been loaded into the class member variable $differenceEngine->mNewContent but before checking if the variable 's value is null. This hook can be used to inject content into said class member variable. $differenceEngine:DifferenceEngine object 'DifferenceEngineMarkPatrolledLink':Allows extensions to change the "mark as patrolled" link which is shown both on the diff header as well as on the bottom of a page, usually wrapped in a span element which has class="patrollink". $differenceEngine:DifferenceEngine object & $markAsPatrolledLink:The "mark as patrolled" link HTML(string) $rcid:Recent change ID(rc_id) for this change(int) 'DifferenceEngineMarkPatrolledRCID':Allows extensions to possibly change the rcid parameter. For example the rcid might be set to zero due to the user being the same as the performer of the change but an extension might still want to show it under certain conditions. & $rcid:rc_id(int) of the change or 0 $differenceEngine:DifferenceEngine object $change:RecentChange object $user:User object representing the current user 'DifferenceEngineNewHeader':Allows extensions to change the $newHeader variable, which contains information about the new revision, such as the revision 's author, whether the revision was marked as a minor edit or not, etc. $differenceEngine:DifferenceEngine object & $newHeader:The string containing the various #mw-diff-otitle[1-5] divs, which include things like revision author info, revision comment, RevisionDelete link and more $formattedRevisionTools:Array containing revision tools, some of which may have been injected with the DiffRevisionTools hook $nextlink:String containing the link to the next revision(if any) $status
Definition: hooks.txt:1263
add( $key, $value, $exptime=0, $flags=0)
static newGood( $value=null)
Factory function for good results.
Definition: StatusValue.php:81
array $locksHeld
Map of (resource path => lock type => count)
Definition: LockManager.php:58
doUnlock(array $paths, $type)
acquireMutexes(MemcachedBagOStuff $memc, array $keys)
$params
getLocksOnServer( $lockSrv, array $pathsByType)
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 null
Definition: hooks.txt:780
Manage locks using memcached servers.
isServerUp( $lockSrv)
This document is intended to provide useful advice for parties seeking to redistribute MediaWiki to end users It s targeted particularly at maintainers for Linux since it s been observed that distribution packages of MediaWiki often break We ve consistently had to recommend that users seeking support use official tarballs instead of their distribution s and this often solves whatever problem the user is having It would be nice if this could such as
Definition: distributors.txt:9
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
releaseMutexes(MemcachedBagOStuff $memc, array $keys)
Base class for memcached clients.
you have access to all of the normal MediaWiki so you can get a DB use the etc For full docs on the Maintenance class
Definition: maintenance.txt:52
__destruct()
Make sure remaining locks get cleared for sanity.
MemcachedBagOStuff [] $cacheServers
Map of (server name => MemcachedBagOStuff)
Allows to change the fields on the form that will be generated $name
Definition: hooks.txt:271
getCache( $lockSrv)
Get the MemcachedBagOStuff object for a $lockSrv.
Version of LockManager that uses a quorum from peer servers for locks.
freeLocksOnServer( $lockSrv, array $pathsByType)
sha1Base36Absolute( $path)
Get the base 36 SHA-1 of a string, padded to 31 digits.