MediaWiki  1.29.1
ChronologyProtector.php
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1 <?php
24 namespace Wikimedia\Rdbms;
25 
26 use Psr\Log\LoggerAwareInterface;
27 use Psr\Log\LoggerInterface;
28 use Psr\Log\NullLogger;
29 use Wikimedia\WaitConditionLoop;
31 
36 class ChronologyProtector implements LoggerAwareInterface {
38  protected $store;
40  protected $logger;
41 
43  protected $key;
45  protected $clientId;
47  protected $waitForPosTime;
49  protected $waitForPosTimeout = self::POS_WAIT_TIMEOUT;
51  protected $enabled = true;
53  protected $wait = true;
54 
56  protected $initialized = false;
58  protected $startupPositions = [];
60  protected $shutdownPositions = [];
62  protected $shutdownTouchDBs = [];
63 
65  const POSITION_TTL = 60;
67  const POS_WAIT_TIMEOUT = 5;
68 
75  public function __construct( BagOStuff $store, array $client, $posTime = null ) {
76  $this->store = $store;
77  $this->clientId = md5( $client['ip'] . "\n" . $client['agent'] );
78  $this->key = $store->makeGlobalKey( __CLASS__, $this->clientId, 'v1' );
79  $this->waitForPosTime = $posTime;
80  $this->logger = new NullLogger();
81  }
82 
83  public function setLogger( LoggerInterface $logger ) {
84  $this->logger = $logger;
85  }
86 
91  public function setEnabled( $enabled ) {
92  $this->enabled = $enabled;
93  }
94 
99  public function setWaitEnabled( $enabled ) {
100  $this->wait = $enabled;
101  }
102 
114  public function initLB( ILoadBalancer $lb ) {
115  if ( !$this->enabled || $lb->getServerCount() <= 1 ) {
116  return; // non-replicated setup or disabled
117  }
118 
119  $this->initPositions();
120 
121  $masterName = $lb->getServerName( $lb->getWriterIndex() );
122  if (
123  isset( $this->startupPositions[$masterName] ) &&
124  $this->startupPositions[$masterName] instanceof DBMasterPos
125  ) {
126  $pos = $this->startupPositions[$masterName];
127  $this->logger->info( __METHOD__ . ": LB for '$masterName' set to pos $pos\n" );
128  $lb->waitFor( $pos );
129  }
130  }
131 
139  public function shutdownLB( ILoadBalancer $lb ) {
140  if ( !$this->enabled ) {
141  return; // not enabled
142  } elseif ( !$lb->hasOrMadeRecentMasterChanges( INF ) ) {
143  // Only save the position if writes have been done on the connection
144  return;
145  }
146 
147  $masterName = $lb->getServerName( $lb->getWriterIndex() );
148  if ( $lb->getServerCount() > 1 ) {
149  $pos = $lb->getMasterPos();
150  $this->logger->info( __METHOD__ . ": LB for '$masterName' has pos $pos\n" );
151  $this->shutdownPositions[$masterName] = $pos;
152  } else {
153  $this->logger->info( __METHOD__ . ": DB '$masterName' touched\n" );
154  }
155  $this->shutdownTouchDBs[$masterName] = 1;
156  }
157 
166  public function shutdown( callable $workCallback = null, $mode = 'sync' ) {
167  if ( !$this->enabled ) {
168  return [];
169  }
170 
172  // Some callers might want to know if a user recently touched a DB.
173  // These writes do not need to block on all datacenters receiving them.
174  foreach ( $this->shutdownTouchDBs as $dbName => $unused ) {
175  $store->set(
176  $this->getTouchedKey( $this->store, $dbName ),
177  microtime( true ),
178  $store::TTL_DAY
179  );
180  }
181 
182  if ( !count( $this->shutdownPositions ) ) {
183  return []; // nothing to save
184  }
185 
186  $this->logger->info( __METHOD__ . ": saving master pos for " .
187  implode( ', ', array_keys( $this->shutdownPositions ) ) . "\n"
188  );
189 
190  // CP-protected writes should overwhemingly go to the master datacenter, so get DC-local
191  // lock to merge the values. Use a DC-local get() and a synchronous all-DC set(). This
192  // makes it possible for the BagOStuff class to write in parallel to all DCs with one RTT.
193  if ( $store->lock( $this->key, 3 ) ) {
194  if ( $workCallback ) {
195  // Let the store run the work before blocking on a replication sync barrier. By the
196  // time it's done with the work, the barrier should be fast if replication caught up.
197  $store->addBusyCallback( $workCallback );
198  }
199  $ok = $store->set(
200  $this->key,
201  self::mergePositions( $store->get( $this->key ), $this->shutdownPositions ),
202  self::POSITION_TTL,
203  ( $mode === 'sync' ) ? $store::WRITE_SYNC : 0
204  );
205  $store->unlock( $this->key );
206  } else {
207  $ok = false;
208  }
209 
210  if ( !$ok ) {
211  $bouncedPositions = $this->shutdownPositions;
212  // Raced out too many times or stash is down
213  $this->logger->warning( __METHOD__ . ": failed to save master pos for " .
214  implode( ', ', array_keys( $this->shutdownPositions ) ) . "\n"
215  );
216  } elseif ( $mode === 'sync' &&
217  $store->getQoS( $store::ATTR_SYNCWRITES ) < $store::QOS_SYNCWRITES_BE
218  ) {
219  // Positions may not be in all datacenters, force LBFactory to play it safe
220  $this->logger->info( __METHOD__ . ": store may not support synchronous writes." );
221  $bouncedPositions = $this->shutdownPositions;
222  } else {
223  $bouncedPositions = [];
224  }
225 
226  return $bouncedPositions;
227  }
228 
234  public function getTouched( $dbName ) {
235  return $this->store->get( $this->getTouchedKey( $this->store, $dbName ) );
236  }
237 
243  private function getTouchedKey( BagOStuff $store, $dbName ) {
244  return $store->makeGlobalKey( __CLASS__, 'mtime', $this->clientId, $dbName );
245  }
246 
250  protected function initPositions() {
251  if ( $this->initialized ) {
252  return;
253  }
254 
255  $this->initialized = true;
256  if ( $this->wait ) {
257  // If there is an expectation to see master positions with a certain min
258  // timestamp, then block until they appear, or until a timeout is reached.
259  if ( $this->waitForPosTime > 0.0 ) {
260  $data = null;
261  $loop = new WaitConditionLoop(
262  function () use ( &$data ) {
263  $data = $this->store->get( $this->key );
264 
265  return ( self::minPosTime( $data ) >= $this->waitForPosTime )
266  ? WaitConditionLoop::CONDITION_REACHED
267  : WaitConditionLoop::CONDITION_CONTINUE;
268  },
270  );
271  $result = $loop->invoke();
272  $waitedMs = $loop->getLastWaitTime() * 1e3;
273 
274  if ( $result == $loop::CONDITION_REACHED ) {
275  $msg = "expected and found pos time {$this->waitForPosTime} ({$waitedMs}ms)";
276  $this->logger->debug( $msg );
277  } else {
278  $msg = "expected but missed pos time {$this->waitForPosTime} ({$waitedMs}ms)";
279  $this->logger->info( $msg );
280  }
281  } else {
282  $data = $this->store->get( $this->key );
283  }
284 
285  $this->startupPositions = $data ? $data['positions'] : [];
286  $this->logger->info( __METHOD__ . ": key is {$this->key} (read)\n" );
287  } else {
288  $this->startupPositions = [];
289  $this->logger->info( __METHOD__ . ": key is {$this->key} (unread)\n" );
290  }
291  }
292 
297  private static function minPosTime( $data ) {
298  if ( !isset( $data['positions'] ) ) {
299  return null;
300  }
301 
302  $min = null;
303  foreach ( $data['positions'] as $pos ) {
304  if ( $pos instanceof DBMasterPos ) {
305  $min = $min ? min( $pos->asOfTime(), $min ) : $pos->asOfTime();
306  }
307  }
308 
309  return $min;
310  }
311 
317  private static function mergePositions( $curValue, array $shutdownPositions ) {
319  if ( $curValue === false ) {
320  $curPositions = $shutdownPositions;
321  } else {
322  $curPositions = $curValue['positions'];
323  // Use the newest positions for each DB master
324  foreach ( $shutdownPositions as $db => $pos ) {
325  if (
326  !isset( $curPositions[$db] ) ||
327  !( $curPositions[$db] instanceof DBMasterPos ) ||
328  $pos->asOfTime() > $curPositions[$db]->asOfTime()
329  ) {
330  $curPositions[$db] = $pos;
331  }
332  }
333  }
334 
335  return [ 'positions' => $curPositions ];
336  }
337 }
Wikimedia\Rdbms\ChronologyProtector\$startupPositions
DBMasterPos[] $startupPositions
Map of (DB master name => position)
Definition: ChronologyProtector.php:58
false
processing should stop and the error should be shown to the user * false
Definition: hooks.txt:189
BagOStuff\getQoS
getQoS( $flag)
Definition: BagOStuff.php:773
Wikimedia\Rdbms\ChronologyProtector\$waitForPosTimeout
int $waitForPosTimeout
Max seconds to wait on positions to appear.
Definition: ChronologyProtector.php:49
Wikimedia\Rdbms\ChronologyProtector\$store
BagOStuff $store
Definition: ChronologyProtector.php:38
Wikimedia\Rdbms\ChronologyProtector\$wait
bool $wait
Whether to check and wait on positions.
Definition: ChronologyProtector.php:53
captcha-old.count
count
Definition: captcha-old.py:225
$result
The index of the header message $result[1]=The index of the body text message $result[2 through n]=Parameters passed to body text message. Please note the header message cannot receive/use parameters. 'ImportHandleLogItemXMLTag':When parsing a XML tag in a log item. Return false to stop further processing of the tag $reader:XMLReader object $logInfo:Array of information 'ImportHandlePageXMLTag':When parsing a XML tag in a page. Return false to stop further processing of the tag $reader:XMLReader object & $pageInfo:Array of information 'ImportHandleRevisionXMLTag':When parsing a XML tag in a page revision. Return false to stop further processing of the tag $reader:XMLReader object $pageInfo:Array of page information $revisionInfo:Array of revision information 'ImportHandleToplevelXMLTag':When parsing a top level XML tag. Return false to stop further processing of the tag $reader:XMLReader object 'ImportHandleUploadXMLTag':When parsing a XML tag in a file upload. Return false to stop further processing of the tag $reader:XMLReader object $revisionInfo:Array of information 'ImportLogInterwikiLink':Hook to change the interwiki link used in log entries and edit summaries for transwiki imports. & $fullInterwikiPrefix:Interwiki prefix, may contain colons. & $pageTitle:String that contains page title. 'ImportSources':Called when reading from the $wgImportSources configuration variable. Can be used to lazy-load the import sources list. & $importSources:The value of $wgImportSources. Modify as necessary. See the comment in DefaultSettings.php for the detail of how to structure this array. 'InfoAction':When building information to display on the action=info page. $context:IContextSource object & $pageInfo:Array of information 'InitializeArticleMaybeRedirect':MediaWiki check to see if title is a redirect. & $title:Title object for the current page & $request:WebRequest & $ignoreRedirect:boolean to skip redirect check & $target:Title/string of redirect target & $article:Article object 'InternalParseBeforeLinks':during Parser 's internalParse method before links but after nowiki/noinclude/includeonly/onlyinclude and other processings. & $parser:Parser object & $text:string containing partially parsed text & $stripState:Parser 's internal StripState object 'InternalParseBeforeSanitize':during Parser 's internalParse method just before the parser removes unwanted/dangerous HTML tags and after nowiki/noinclude/includeonly/onlyinclude and other processings. Ideal for syntax-extensions after template/parser function execution which respect nowiki and HTML-comments. & $parser:Parser object & $text:string containing partially parsed text & $stripState:Parser 's internal StripState object 'InterwikiLoadPrefix':When resolving if a given prefix is an interwiki or not. Return true without providing an interwiki to continue interwiki search. $prefix:interwiki prefix we are looking for. & $iwData:output array describing the interwiki with keys iw_url, iw_local, iw_trans and optionally iw_api and iw_wikiid. 'InvalidateEmailComplete':Called after a user 's email has been invalidated successfully. $user:user(object) whose email is being invalidated 'IRCLineURL':When constructing the URL to use in an IRC notification. Callee may modify $url and $query, URL will be constructed as $url . $query & $url:URL to index.php & $query:Query string $rc:RecentChange object that triggered url generation 'IsFileCacheable':Override the result of Article::isFileCacheable()(if true) & $article:article(object) being checked 'IsTrustedProxy':Override the result of IP::isTrustedProxy() & $ip:IP being check & $result:Change this value to override the result of IP::isTrustedProxy() 'IsUploadAllowedFromUrl':Override the result of UploadFromUrl::isAllowedUrl() $url:URL used to upload from & $allowed:Boolean indicating if uploading is allowed for given URL 'isValidEmailAddr':Override the result of Sanitizer::validateEmail(), for instance to return false if the domain name doesn 't match your organization. $addr:The e-mail address entered by the user & $result:Set this and return false to override the internal checks 'isValidPassword':Override the result of User::isValidPassword() $password:The password entered by the user & $result:Set this and return false to override the internal checks $user:User the password is being validated for 'Language::getMessagesFileName':$code:The language code or the language we 're looking for a messages file for & $file:The messages file path, you can override this to change the location. 'LanguageGetMagic':DEPRECATED! Use $magicWords in a file listed in $wgExtensionMessagesFiles instead. Use this to define synonyms of magic words depending of the language & $magicExtensions:associative array of magic words synonyms $lang:language code(string) 'LanguageGetNamespaces':Provide custom ordering for namespaces or remove namespaces. Do not use this hook to add namespaces. Use CanonicalNamespaces for that. & $namespaces:Array of namespaces indexed by their numbers 'LanguageGetSpecialPageAliases':DEPRECATED! Use $specialPageAliases in a file listed in $wgExtensionMessagesFiles instead. Use to define aliases of special pages names depending of the language & $specialPageAliases:associative array of magic words synonyms $lang:language code(string) 'LanguageGetTranslatedLanguageNames':Provide translated language names. & $names:array of language code=> language name $code:language of the preferred translations 'LanguageLinks':Manipulate a page 's language links. This is called in various places to allow extensions to define the effective language links for a page. $title:The page 's Title. & $links:Array with elements of the form "language:title" in the order that they will be output. & $linkFlags:Associative array mapping prefixed links to arrays of flags. Currently unused, but planned to provide support for marking individual language links in the UI, e.g. for featured articles. 'LanguageSelector':Hook to change the language selector available on a page. $out:The output page. $cssClassName:CSS class name of the language selector. 'LinkBegin':DEPRECATED! Use HtmlPageLinkRendererBegin instead. Used when generating internal and interwiki links in Linker::link(), before processing starts. Return false to skip default processing and return $ret. See documentation for Linker::link() for details on the expected meanings of parameters. $skin:the Skin object $target:the Title that the link is pointing to & $html:the contents that the< a > tag should have(raw HTML) $result
Definition: hooks.txt:1954
use
as see the revision history and available at free of to any person obtaining a copy of this software and associated documentation to deal in the Software without including without limitation the rights to use
Definition: MIT-LICENSE.txt:10
Wikimedia\Rdbms\ChronologyProtector\$shutdownTouchDBs
float[] $shutdownTouchDBs
Map of (DB master name => 1)
Definition: ChronologyProtector.php:62
Wikimedia\Rdbms
Definition: ChronologyProtector.php:24
Wikimedia\Rdbms\ChronologyProtector\$initialized
bool $initialized
Whether the client data was loaded.
Definition: ChronologyProtector.php:56
Wikimedia\Rdbms\DBMasterPos
An object representing a master or replica DB position in a replicated setup.
Definition: DBMasterPos.php:10
BagOStuff
interface is intended to be more or less compatible with the PHP memcached client.
Definition: BagOStuff.php:47
Wikimedia\Rdbms\ILoadBalancer\getServerCount
getServerCount()
Get the number of defined servers (not the number of open connections)
Wikimedia\Rdbms\ChronologyProtector\$logger
LoggerInterface $logger
Definition: ChronologyProtector.php:40
Wikimedia\Rdbms\ChronologyProtector\getTouched
getTouched( $dbName)
Definition: ChronologyProtector.php:234
php
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
Wikimedia\Rdbms\ChronologyProtector\setLogger
setLogger(LoggerInterface $logger)
Definition: ChronologyProtector.php:83
BagOStuff\unlock
unlock( $key)
Release an advisory lock on a key string.
Definition: BagOStuff.php:443
key
design txt This is a brief overview of the new design More thorough and up to date information is available on the documentation wiki at etc Handles the details of getting and saving to the user table of the and dealing with sessions and cookies OutputPage Encapsulates the entire HTML page that will be sent in response to any server request It is used by calling its functions to add in any and then calling but I prefer the flexibility This should also do the output encoding The system allocates a global one in $wgOut Title Represents the title of an and does all the work of translating among various forms such as plain database key
Definition: design.txt:25
Wikimedia\Rdbms\ChronologyProtector\minPosTime
static minPosTime( $data)
Definition: ChronologyProtector.php:297
Wikimedia\Rdbms\ChronologyProtector\initPositions
initPositions()
Load in previous master positions for the client.
Definition: ChronologyProtector.php:250
Wikimedia\Rdbms\ILoadBalancer\getServerName
getServerName( $i)
Get the host name or IP address of the server with the specified index Prefer a readable name if avai...
Wikimedia\Rdbms\ChronologyProtector\setWaitEnabled
setWaitEnabled( $enabled)
Definition: ChronologyProtector.php:99
store
MediaWiki s SiteStore can be cached and stored in a flat in a json format If the SiteStore is frequently the file cache may provide a performance benefit over a database store
Definition: sitescache.txt:1
Wikimedia\Rdbms\ILoadBalancer\getMasterPos
getMasterPos()
Get the current master position for chronology control purposes.
Wikimedia\Rdbms\ILoadBalancer\getWriterIndex
getWriterIndex()
BagOStuff\addBusyCallback
addBusyCallback(callable $workCallback)
Let a callback be run to avoid wasting time on special blocking calls.
Definition: BagOStuff.php:654
Wikimedia\Rdbms\ILoadBalancer\waitFor
waitFor( $pos)
Set the master wait position.
Wikimedia\Rdbms\ChronologyProtector\$key
string $key
Storage key name.
Definition: ChronologyProtector.php:43
Wikimedia\Rdbms\ChronologyProtector\$enabled
bool $enabled
Whether to no-op all method calls.
Definition: ChronologyProtector.php:51
Wikimedia\Rdbms\ChronologyProtector\initLB
initLB(ILoadBalancer $lb)
Initialise a ILoadBalancer to give it appropriate chronology protection.
Definition: ChronologyProtector.php:114
Wikimedia\Rdbms\ILoadBalancer\hasOrMadeRecentMasterChanges
hasOrMadeRecentMasterChanges( $age=null)
Check if this load balancer object had any recent or still pending writes issued against it by this P...
Wikimedia\Rdbms\ChronologyProtector\__construct
__construct(BagOStuff $store, array $client, $posTime=null)
Definition: ChronologyProtector.php:75
Wikimedia\Rdbms\ChronologyProtector\shutdownLB
shutdownLB(ILoadBalancer $lb)
Notify the ChronologyProtector that the ILoadBalancer is about to shut down.
Definition: ChronologyProtector.php:139
BagOStuff\get
get( $key, $flags=0, $oldFlags=null)
Get an item with the given key.
Definition: BagOStuff.php:179
Wikimedia\Rdbms\ChronologyProtector\shutdown
shutdown(callable $workCallback=null, $mode='sync')
Notify the ChronologyProtector that the LBFactory is done calling shutdownLB() for now.
Definition: ChronologyProtector.php:166
BagOStuff\makeGlobalKey
makeGlobalKey()
Make a global cache key.
Definition: BagOStuff.php:753
Wikimedia\Rdbms\ChronologyProtector
Class for ensuring a consistent ordering of events as seen by the user, despite replication.
Definition: ChronologyProtector.php:36
as
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
Wikimedia\Rdbms\ChronologyProtector\$clientId
string $clientId
Hash of client parameters.
Definition: ChronologyProtector.php:45
BagOStuff\lock
lock( $key, $timeout=6, $expiry=6, $rclass='')
Acquire an advisory lock on a key string.
Definition: BagOStuff.php:403
Wikimedia\Rdbms\ChronologyProtector\$shutdownPositions
DBMasterPos[] $shutdownPositions
Map of (DB master name => position)
Definition: ChronologyProtector.php:60
BagOStuff\set
set( $key, $value, $exptime=0, $flags=0)
Set an item.
Wikimedia\Rdbms\ChronologyProtector\$waitForPosTime
float null $waitForPosTime
Minimum UNIX timestamp of 1+ expected startup positions.
Definition: ChronologyProtector.php:47
Wikimedia\Rdbms\ChronologyProtector\getTouchedKey
getTouchedKey(BagOStuff $store, $dbName)
Definition: ChronologyProtector.php:243
Wikimedia\Rdbms\ChronologyProtector\setEnabled
setEnabled( $enabled)
Definition: ChronologyProtector.php:91
Wikimedia\Rdbms\ChronologyProtector\mergePositions
static mergePositions( $curValue, array $shutdownPositions)
Definition: ChronologyProtector.php:317
Wikimedia\Rdbms\ILoadBalancer
Database cluster connection, tracking, load balancing, and transaction manager interface.
Definition: ILoadBalancer.php:79
array
the array() calling protocol came about after MediaWiki 1.4rc1.