MediaWiki  master
ForkController.php
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1 <?php
23 
34  protected $children = [], $childNumber = 0;
35  protected $termReceived = false;
36  protected $flags = 0, $procsToStart = 0;
37 
38  protected static $restartableSignals = [
39  SIGFPE,
40  SIGILL,
41  SIGSEGV,
42  SIGBUS,
43  SIGABRT,
44  SIGSYS,
45  SIGPIPE,
46  SIGXCPU,
47  SIGXFSZ,
48  ];
49 
54  const RESTART_ON_ERROR = 1;
55 
56  public function __construct( $numProcs, $flags = 0 ) {
57  if ( !wfIsCLI() ) {
58  throw new MWException( "ForkController cannot be used from the web." );
59  }
60  $this->procsToStart = $numProcs;
61  $this->flags = $flags;
62  }
63 
75  public function start() {
76  // Trap SIGTERM
77  pcntl_signal( SIGTERM, [ $this, 'handleTermSignal' ], false );
78 
79  do {
80  // Start child processes
81  if ( $this->procsToStart ) {
82  if ( $this->forkWorkers( $this->procsToStart ) == 'child' ) {
83  return 'child';
84  }
85  $this->procsToStart = 0;
86  }
87 
88  // Check child status
89  $status = false;
90  $deadPid = pcntl_wait( $status );
91 
92  if ( $deadPid > 0 ) {
93  // Respond to child process termination
94  unset( $this->children[$deadPid] );
95  if ( $this->flags & self::RESTART_ON_ERROR ) {
96  if ( pcntl_wifsignaled( $status ) ) {
97  // Restart if the signal was abnormal termination
98  // Don't restart if it was deliberately killed
99  $signal = pcntl_wtermsig( $status );
100  if ( in_array( $signal, self::$restartableSignals ) ) {
101  echo "Worker exited with signal $signal, restarting\n";
102  $this->procsToStart++;
103  }
104  } elseif ( pcntl_wifexited( $status ) ) {
105  // Restart on non-zero exit status
106  $exitStatus = pcntl_wexitstatus( $status );
107  if ( $exitStatus != 0 ) {
108  echo "Worker exited with status $exitStatus, restarting\n";
109  $this->procsToStart++;
110  } else {
111  echo "Worker exited normally\n";
112  }
113  }
114  }
115  // Throttle restarts
116  if ( $this->procsToStart ) {
117  usleep( 500000 );
118  }
119  }
120 
121  // Run signal handlers
122  if ( function_exists( 'pcntl_signal_dispatch' ) ) {
123  pcntl_signal_dispatch();
124  } else {
125  declare( ticks = 1 ) {
126  // @phan-suppress-next-line PhanPluginDuplicateExpressionAssignment
127  $status = $status;
128  }
129  }
130  // Respond to TERM signal
131  if ( $this->termReceived ) {
132  foreach ( $this->children as $childPid => $unused ) {
133  posix_kill( $childPid, SIGTERM );
134  }
135  $this->termReceived = false;
136  }
137  } while ( count( $this->children ) );
138  pcntl_signal( SIGTERM, SIG_DFL );
139  return 'done';
140  }
141 
148  public function getChildNumber() {
149  return $this->childNumber;
150  }
151 
152  protected function prepareEnvironment() {
153  global $wgMemc;
154  // Don't share DB, storage, or memcached connections
155  MediaWikiServices::resetChildProcessServices();
161  $wgMemc = null;
162  }
163 
170  protected function forkWorkers( $numProcs ) {
171  $this->prepareEnvironment();
172 
173  // Create the child processes
174  for ( $i = 0; $i < $numProcs; $i++ ) {
175  // Do the fork
176  $pid = pcntl_fork();
177  if ( $pid === -1 || $pid === false ) {
178  echo "Error creating child processes\n";
179  exit( 1 );
180  }
181 
182  if ( !$pid ) {
183  $this->initChild();
184  $this->childNumber = $i;
185  return 'child';
186  } else {
187  // This is the parent process
188  $this->children[$pid] = true;
189  }
190  }
191 
192  return 'parent';
193  }
194 
195  protected function initChild() {
196  global $wgMemc, $wgMainCacheType;
197  $wgMemc = wfGetCache( $wgMainCacheType );
198  $this->children = null;
199  pcntl_signal( SIGTERM, SIG_DFL );
200  }
201 
202  protected function handleTermSignal( $signal ) {
203  $this->termReceived = true;
204  }
205 }
forkWorkers( $numProcs)
Fork a number of worker processes.
globals will be eliminated from MediaWiki replaced by an application object which would be passed to constructors Whether that would be an convenient solution remains to be but certainly PHP makes such object oriented programming models easier than they were in previous versions For the time being MediaWiki programmers will have to work in an environment with some global context At the time of globals were initialised on startup by MediaWiki of these were configuration which are documented in DefaultSettings php There is no comprehensive documentation for the remaining however some of the most important ones are listed below They are typically initialised either in index php or in Setup php $wgTitle Title object created from the request URL $wgOut OutputPage object for HTTP response $wgUser User object for the user associated with the current request $wgLang Language object selected by user preferences $wgContLang Language object associated with the wiki being viewed $wgParser Parser object Parser extensions register their hooks here $wgRequest WebRequest to get request data $wgMemc
Definition: globals.txt:25
CACHE_MEMCACHED $wgMainCacheType
Definition: memcached.txt:63
Apache License January AND DISTRIBUTION Definitions License shall mean the terms and conditions for use
wfGetCache( $cacheType)
Get a specific cache object.
const RESTART_ON_ERROR
Pass this flag to __construct() to cause the class to automatically restart workers that exit with no...
static destroySingletons()
Destroy all singleton() instances.
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 MediaWikiServices
Definition: injection.txt:23
static destroySingleton()
Destroy the singleton instance.
handleTermSignal( $signal)
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:1244
start()
Start the child processes.
Class for managing forking command line scripts.
static destroySingletons()
Destroy the singleton instances.
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:767
getChildNumber()
Get the number of the child currently running.
wfIsCLI()
Check if we are running from the commandline.
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
static $restartableSignals
static clear()
Clear all the cached instances.
__construct( $numProcs, $flags=0)
static destroySingletons()
Destroy the singleton instances.