MediaWiki  1.28.3
PoolCounterRedis.php
Go to the documentation of this file.
1 <?php
22 
56  protected $ring;
58  protected $pool;
60  protected $logger;
62  protected $serversByLabel;
64  protected $keySha1;
66  protected $lockTTL;
67 
69  protected $conn;
71  protected $slot;
73  protected $onRelease;
75  protected $session;
77  protected $slotTime;
78 
79  const AWAKE_ONE = 1; // wake-up if when a slot can be taken from an existing process
80  const AWAKE_ALL = 2; // wake-up if an existing process finishes and wake up such others
81 
83  protected static $active = null;
84 
85  function __construct( $conf, $type, $key ) {
86  parent::__construct( $conf, $type, $key );
87 
88  $this->serversByLabel = $conf['servers'];
89  $this->ring = new HashRing( array_fill_keys( array_keys( $conf['servers'] ), 100 ) );
90 
91  $conf['redisConfig']['serializer'] = 'none'; // for use with Lua
92  $this->pool = RedisConnectionPool::singleton( $conf['redisConfig'] );
93  $this->logger = \MediaWiki\Logger\LoggerFactory::getInstance( 'redis' );
94 
95  $this->keySha1 = sha1( $this->key );
96  $met = ini_get( 'max_execution_time' ); // usually 0 in CLI mode
97  $this->lockTTL = $met ? 2 * $met : 3600;
98 
99  if ( self::$active === null ) {
100  self::$active = [];
101  register_shutdown_function( [ __CLASS__, 'releaseAll' ] );
102  }
103  }
104 
108  protected function getConnection() {
109  if ( !isset( $this->conn ) ) {
110  $conn = false;
111  $servers = $this->ring->getLocations( $this->key, 3 );
112  ArrayUtils::consistentHashSort( $servers, $this->key );
113  foreach ( $servers as $server ) {
114  $conn = $this->pool->getConnection( $this->serversByLabel[$server], $this->logger );
115  if ( $conn ) {
116  break;
117  }
118  }
119  if ( !$conn ) {
120  return Status::newFatal( 'pool-servererror', implode( ', ', $servers ) );
121  }
122  $this->conn = $conn;
123  }
124  return Status::newGood( $this->conn );
125  }
126 
127  function acquireForMe() {
128  $status = $this->precheckAcquire();
129  if ( !$status->isGood() ) {
130  return $status;
131  }
132 
133  return $this->waitForSlotOrNotif( self::AWAKE_ONE );
134  }
135 
136  function acquireForAnyone() {
137  $status = $this->precheckAcquire();
138  if ( !$status->isGood() ) {
139  return $status;
140  }
141 
142  return $this->waitForSlotOrNotif( self::AWAKE_ALL );
143  }
144 
145  function release() {
146  if ( $this->slot === null ) {
147  return Status::newGood( PoolCounter::NOT_LOCKED ); // not locked
148  }
149 
150  $status = $this->getConnection();
151  if ( !$status->isOK() ) {
152  return $status;
153  }
154  $conn = $status->value;
155 
156  // @codingStandardsIgnoreStart Generic.Files.LineLength
157  static $script =
159 <<<LUA
160  local kSlots,kSlotsNextRelease,kWakeup,kWaiting = unpack(KEYS)
161  local rMaxWorkers,rExpiry,rSlot,rSlotTime,rAwakeAll,rTime = unpack(ARGV)
162  -- Add the slots back to the list (if rSlot is "w" then it is not a slot).
163  -- Treat the list as expired if the "next release" time sorted-set is missing.
164  if rSlot ~= 'w' and redis.call('exists',kSlotsNextRelease) == 1 then
165  if 1*redis.call('zScore',kSlotsNextRelease,rSlot) ~= (rSlotTime + rExpiry) then
166  -- Slot lock expired and was released already
167  elseif redis.call('lLen',kSlots) >= 1*rMaxWorkers then
168  -- Slots somehow got out of sync; reset the list for sanity
169  redis.call('del',kSlots,kSlotsNextRelease)
170  elseif redis.call('lLen',kSlots) == (1*rMaxWorkers - 1) and redis.call('zCard',kWaiting) == 0 then
171  -- Slot list will be made full; clear it to save space (it re-inits as needed)
172  -- since nothing is waiting on being unblocked by a push to the list
173  redis.call('del',kSlots,kSlotsNextRelease)
174  else
175  -- Add slot back to pool and update the "next release" time
176  redis.call('rPush',kSlots,rSlot)
177  redis.call('zAdd',kSlotsNextRelease,rTime + 30,rSlot)
178  -- Always keep renewing the expiry on use
179  redis.call('expireAt',kSlots,math.ceil(rTime + rExpiry))
180  redis.call('expireAt',kSlotsNextRelease,math.ceil(rTime + rExpiry))
181  end
182  end
183  -- Update an ephemeral list to wake up other clients that can
184  -- reuse any cached work from this process. Only do this if no
185  -- slots are currently free (e.g. clients could be waiting).
186  if 1*rAwakeAll == 1 then
187  local count = redis.call('zCard',kWaiting)
188  for i = 1,count do
189  redis.call('rPush',kWakeup,'w')
190  end
191  redis.call('pexpire',kWakeup,1)
192  end
193  return 1
194 LUA;
195  // @codingStandardsIgnoreEnd
196 
197  try {
198  $conn->luaEval( $script,
199  [
200  $this->getSlotListKey(),
201  $this->getSlotRTimeSetKey(),
202  $this->getWakeupListKey(),
203  $this->getWaitSetKey(),
204  $this->workers,
205  $this->lockTTL,
206  $this->slot,
207  $this->slotTime, // used for CAS-style sanity check
208  ( $this->onRelease === self::AWAKE_ALL ) ? 1 : 0,
209  microtime( true )
210  ],
211  4 # number of first argument(s) that are keys
212  );
213  } catch ( RedisException $e ) {
214  return Status::newFatal( 'pool-error-unknown', $e->getMessage() );
215  }
216 
217  $this->slot = null;
218  $this->slotTime = null;
219  $this->onRelease = null;
220  unset( self::$active[$this->session] );
221 
222  $this->onRelease();
223 
225  }
226 
231  protected function waitForSlotOrNotif( $doWakeup ) {
232  if ( $this->slot !== null ) {
233  return Status::newGood( PoolCounter::LOCK_HELD ); // already acquired
234  }
235 
236  $status = $this->getConnection();
237  if ( !$status->isOK() ) {
238  return $status;
239  }
240  $conn = $status->value;
241 
242  $now = microtime( true );
243  try {
244  $slot = $this->initAndPopPoolSlotList( $conn, $now );
245  if ( ctype_digit( $slot ) ) {
246  // Pool slot acquired by this process
247  $slotTime = $now;
248  } elseif ( $slot === 'QUEUE_FULL' ) {
249  // Too many processes are waiting for pooled processes to finish
251  } elseif ( $slot === 'QUEUE_WAIT' ) {
252  // This process is now registered as waiting
253  $keys = ( $doWakeup == self::AWAKE_ALL )
254  // Wait for an open slot or wake-up signal (preferring the latter)
255  ? [ $this->getWakeupListKey(), $this->getSlotListKey() ]
256  // Just wait for an actual pool slot
257  : [ $this->getSlotListKey() ];
258 
259  $res = $conn->blPop( $keys, $this->timeout );
260  if ( $res === [] ) {
261  $conn->zRem( $this->getWaitSetKey(), $this->session ); // no longer waiting
263  }
264 
265  $slot = $res[1]; // pool slot or "w" for wake-up notifications
266  $slotTime = microtime( true ); // last microtime() was a few RTTs ago
267  // Unregister this process as waiting and bump slot "next release" time
269  } else {
270  return Status::newFatal( 'pool-error-unknown', "Server gave slot '$slot'." );
271  }
272  } catch ( RedisException $e ) {
273  return Status::newFatal( 'pool-error-unknown', $e->getMessage() );
274  }
275 
276  if ( $slot !== 'w' ) {
277  $this->slot = $slot;
278  $this->slotTime = $slotTime;
279  $this->onRelease = $doWakeup;
280  self::$active[$this->session] = $this;
281  }
282 
283  $this->onAcquire();
284 
286  }
287 
293  protected function initAndPopPoolSlotList( RedisConnRef $conn, $now ) {
294  static $script =
296 <<<LUA
297  local kSlots,kSlotsNextRelease,kSlotWaits = unpack(KEYS)
298  local rMaxWorkers,rMaxQueue,rTimeout,rExpiry,rSess,rTime = unpack(ARGV)
299  -- Initialize if the "next release" time sorted-set is empty. The slot key
300  -- itself is empty if all slots are busy or when nothing is initialized.
301  -- If the list is empty but the set is not, then it is the latter case.
302  -- For sanity, if the list exists but not the set, then reset everything.
303  if redis.call('exists',kSlotsNextRelease) == 0 then
304  redis.call('del',kSlots)
305  for i = 1,1*rMaxWorkers do
306  redis.call('rPush',kSlots,i)
307  redis.call('zAdd',kSlotsNextRelease,-1,i)
308  end
309  -- Otherwise do maintenance to clean up after network partitions
310  else
311  -- Find stale slot locks and add free them (avoid duplicates for sanity)
312  local staleLocks = redis.call('zRangeByScore',kSlotsNextRelease,0,rTime)
313  for k,slot in ipairs(staleLocks) do
314  redis.call('lRem',kSlots,0,slot)
315  redis.call('rPush',kSlots,slot)
316  redis.call('zAdd',kSlotsNextRelease,rTime + 30,slot)
317  end
318  -- Find stale wait slot entries and remove them
319  redis.call('zRemRangeByScore',kSlotWaits,0,rTime - 2*rTimeout)
320  end
321  local slot
322  -- Try to acquire a slot if possible now
323  if redis.call('lLen',kSlots) > 0 then
324  slot = redis.call('lPop',kSlots)
325  -- Update the slot "next release" time
326  redis.call('zAdd',kSlotsNextRelease,rTime + rExpiry,slot)
327  elseif redis.call('zCard',kSlotWaits) >= 1*rMaxQueue then
328  slot = 'QUEUE_FULL'
329  else
330  slot = 'QUEUE_WAIT'
331  -- Register this process as waiting
332  redis.call('zAdd',kSlotWaits,rTime,rSess)
333  redis.call('expireAt',kSlotWaits,math.ceil(rTime + 2*rTimeout))
334  end
335  -- Always keep renewing the expiry on use
336  redis.call('expireAt',kSlots,math.ceil(rTime + rExpiry))
337  redis.call('expireAt',kSlotsNextRelease,math.ceil(rTime + rExpiry))
338  return slot
339 LUA;
340  return $conn->luaEval( $script,
341  [
342  $this->getSlotListKey(),
343  $this->getSlotRTimeSetKey(),
344  $this->getWaitSetKey(),
345  $this->workers,
346  $this->maxqueue,
347  $this->timeout,
348  $this->lockTTL,
349  $this->session,
350  $now
351  ],
352  3 # number of first argument(s) that are keys
353  );
354  }
355 
362  protected function registerAcquisitionTime( RedisConnRef $conn, $slot, $now ) {
363  static $script =
365 <<<LUA
366  local kSlots,kSlotsNextRelease,kSlotWaits = unpack(KEYS)
367  local rSlot,rExpiry,rSess,rTime = unpack(ARGV)
368  -- If rSlot is 'w' then the client was told to wake up but got no slot
369  if rSlot ~= 'w' then
370  -- Update the slot "next release" time
371  redis.call('zAdd',kSlotsNextRelease,rTime + rExpiry,rSlot)
372  -- Always keep renewing the expiry on use
373  redis.call('expireAt',kSlots,math.ceil(rTime + rExpiry))
374  redis.call('expireAt',kSlotsNextRelease,math.ceil(rTime + rExpiry))
375  end
376  -- Unregister this process as waiting
377  redis.call('zRem',kSlotWaits,rSess)
378  return 1
379 LUA;
380  return $conn->luaEval( $script,
381  [
382  $this->getSlotListKey(),
383  $this->getSlotRTimeSetKey(),
384  $this->getWaitSetKey(),
385  $slot,
386  $this->lockTTL,
387  $this->session,
388  $now
389  ],
390  3 # number of first argument(s) that are keys
391  );
392  }
393 
397  protected function getSlotListKey() {
398  return "poolcounter:l-slots-{$this->keySha1}-{$this->workers}";
399  }
400 
404  protected function getSlotRTimeSetKey() {
405  return "poolcounter:z-renewtime-{$this->keySha1}-{$this->workers}";
406  }
407 
411  protected function getWaitSetKey() {
412  return "poolcounter:z-wait-{$this->keySha1}-{$this->workers}";
413  }
414 
418  protected function getWakeupListKey() {
419  return "poolcounter:l-wakeup-{$this->keySha1}-{$this->workers}";
420  }
421 
425  public static function releaseAll() {
426  foreach ( self::$active as $poolCounter ) {
427  try {
428  if ( $poolCounter->slot !== null ) {
429  $poolCounter->release();
430  }
431  } catch ( Exception $e ) {
432  }
433  }
434  }
435 }
static consistentHashSort(&$array, $key, $separator="\000")
Sort the given array in a pseudo-random order which depends only on the given key and each element va...
Definition: ArrayUtils.php:49
luaEval($script, array $params, $numKeys)
LoggerInterface $logger
#define the
table suitable for use with IDatabase::select()
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 then executing the whole list after the page is displayed We don t do anything smart like collating updates to the same table or such because the list is almost always going to have just one item on if that
Definition: deferred.txt:11
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
precheckAcquire()
Checks that the lock request is sane.
const LOCKED
Definition: PoolCounter.php:47
array $serversByLabel
(server label => host) map
Apache License January AND DISTRIBUTION Definitions License shall mean the terms and conditions for use
onRelease()
Update any lock tracking information when the lock is released.
div flags Integer display flags(NO_ACTION_LINK, NO_EXTRA_USER_LINKS) 'LogException'returning false will NOT prevent logging $e
Definition: hooks.txt:2106
static newFatal($message)
Factory function for fatal errors.
Definition: StatusValue.php:63
We use the convention $dbr for read and $dbw for write to help you keep track of whether the database object is a the world will explode Or to be a subsequent write query which succeeded on the master may fail when replicated to the slave due to a unique key collision Replication on the slave will stop and it may take hours to repair the database and get it back online Setting read_only in my cnf on the slave will avoid this but given the dire we prefer to have as many checks as possible We provide a but the wrapper functions like please read the documentation for except in special pages derived from QueryPage It s a common pitfall for new developers to submit code containing SQL queries which examine huge numbers of rows Remember that COUNT * is(N), counting rows in atable is like counting beans in a bucket.------------------------------------------------------------------------Replication------------------------------------------------------------------------The largest installation of MediaWiki, Wikimedia, uses a large set ofslave MySQL servers replicating writes made to a master MySQL server.Itis important to understand the issues associated with this setup if youwant to write code destined for Wikipedia.It's often the case that the best algorithm to use for a given taskdepends on whether or not replication is in use.Due to our unabashedWikipedia-centrism, we often just use the replication-friendly version, but if you like, you can use wfGetLB() ->getServerCount() > 1 tocheck to see if replication is in use.===Lag===Lag primarily occurs when large write queries are sent to the master.Writes on the master are executed in parallel, but they are executed inserial when they are replicated to the slaves.The master writes thequery to the binlog when the transaction is committed.The slaves pollthe binlog and start executing the query as soon as it appears.They canservice reads while they are performing a write query, but will not readanything more from the binlog and thus will perform no more writes.Thismeans that if the write query runs for a long time, the slaves will lagbehind the master for the time it takes for the write query to complete.Lag can be exacerbated by high read load.MediaWiki's load balancer willstop sending reads to a slave when it is lagged by more than 30 seconds.If the load ratios are set incorrectly, or if there is too much loadgenerally, this may lead to a slave permanently hovering around 30seconds lag.If all slaves are lagged by more than 30 seconds, MediaWiki will stopwriting to the database.All edits and other write operations will berefused, with an error returned to the user.This gives the slaves achance to catch up.Before we had this mechanism, the slaves wouldregularly lag by several minutes, making review of recent editsdifficult.In addition to this, MediaWiki attempts to ensure that the user seesevents occurring on the wiki in chronological order.A few seconds of lagcan be tolerated, as long as the user sees a consistent picture fromsubsequent requests.This is done by saving the master binlog positionin the session, and then at the start of each request, waiting for theslave to catch up to that position before doing any reads from it.Ifthis wait times out, reads are allowed anyway, but the request isconsidered to be in"lagged slave mode".Lagged slave mode can bechecked by calling wfGetLB() ->getLaggedSlaveMode().The onlypractical consequence at present is a warning displayed in the pagefooter.===Lag avoidance===To avoid excessive lag, queries which write large numbers of rows shouldbe split up, generally to write one row at a time.Multi-row INSERT...SELECT queries are the worst offenders should be avoided altogether.Instead do the select first and then the insert.===Working with lag===Despite our best efforts, it's not practical to guarantee a low-lagenvironment.Lag will usually be less than one second, but mayoccasionally be up to 30 seconds.For scalability, it's very importantto keep load on the master low, so simply sending all your queries tothe master is not the answer.So when you have a genuine need forup-to-date data, the following approach is advised:1) Do a quick query to the master for a sequence number or timestamp 2) Run the full query on the slave and check if it matches the data you gotfrom the master 3) If it doesn't, run the full query on the masterTo avoid swamping the master every time the slaves lag, use of thisapproach should be kept to a minimum.In most cases you should just readfrom the slave and let the user deal with the delay.------------------------------------------------------------------------Lock contention------------------------------------------------------------------------Due to the high write rate on Wikipedia(and some other wikis), MediaWiki developers need to be very careful to structure their writesto avoid long-lasting locks.By default, MediaWiki opens a transactionat the first query, and commits it before the output is sent.Locks willbe held from the time when the query is done until the commit.So youcan reduce lock time by doing as much processing as possible before youdo your write queries.Often this approach is not good enough, and it becomes necessary toenclose small groups of queries in their own transaction.Use thefollowing syntax:$dbw=wfGetDB(DB_MASTER
waitForSlotOrNotif($doWakeup)
Apache License January AND DISTRIBUTION Definitions License shall mean the terms and conditions for and distribution as defined by Sections through of this document Licensor shall mean the copyright owner or entity authorized by the copyright owner that is granting the License Legal Entity shall mean the union of the acting entity and all other entities that control are controlled by or are under common control with that entity For the purposes of this definition control direct or to cause the direction or management of such whether by contract or including but not limited to software source documentation and configuration files Object form shall mean any form resulting from mechanical transformation or translation of a Source including but not limited to compiled object generated and conversions to other media types Work shall mean the work of whether in Source or Object made available under the as indicated by a copyright notice that is included in or attached to the whether in Source or Object that is based or other modifications as a an original work of authorship For the purposes of this Derivative Works shall not include works that remain separable from
globals txt Globals are evil The original MediaWiki code relied on globals for processing context far too often MediaWiki development since then has been a story of slowly moving context out of global variables and into objects Storing processing context in object member variables allows those objects to be reused in a much more flexible way Consider the elegance of
database rows
Definition: globals.txt:10
static getInstance($channel)
Get a named logger instance from the currently configured logger factory.
MediaWiki has optional support for a high distributed memory object caching system For general information on but for a larger site with heavy like it should help lighten the load on the database servers by caching data and objects in Ubuntu and probably other Linux distributions If there s no package available for your you can compile it from epoll rt patch for Linux is current Memcached and libevent are under BSD style licenses The server should run on Linux and other Unix like systems you can run multiple servers on one machine or on multiple machines on a network
Definition: memcached.txt:16
null for the local wiki Added in
Definition: hooks.txt:1559
__construct($conf, $type, $key)
in this case you re responsible for computing and outputting the entire conflict i e
Definition: hooks.txt:1380
int $slotTime
UNIX timestamp.
const NOT_LOCKED
Definition: PoolCounter.php:52
The ContentHandler facility adds support for arbitrary content types on wiki instead of relying on wikitext for everything It was introduced in MediaWiki Each kind of and so on Built in content types are
An extension or a local will often add custom code to the function with or without a global variable For someone wanting email notification when an article is shown may add
Definition: hooks.txt:51
static singleton(array $options)
Convenience class for weighted consistent hash rings.
Definition: HashRing.php:29
int $onRelease
AWAKE_* constant.
static PoolCounterRedis[] $active
List of active PoolCounterRedis objects in this script.
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
string $keySha1
SHA-1 of the key.
$res
Definition: database.txt:21
string $key
All workers with the same key share the lock.
Definition: PoolCounter.php:58
it s the revision text itself In either if gzip is set
Definition: hooks.txt:2707
Version of PoolCounter that uses Redis.
RedisConnectionPool $pool
and(b) You must cause any modified files to carry prominent notices stating that You changed the files
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 save
Definition: deferred.txt:4
int $lockTTL
TTL for locks to expire (work should finish in this time)
static newGood($value=null)
Factory function for good results.
Definition: StatusValue.php:76
Apache License January AND DISTRIBUTION Definitions License shall mean the terms and conditions for and distribution as defined by Sections through of this document Licensor shall mean the copyright owner or entity authorized by the copyright owner that is granting the License Legal Entity shall mean the union of the acting entity and all other entities that control are controlled by or are under common control with that entity For the purposes of this definition control direct or to cause the direction or management of such whether by contract or including but not limited to software source documentation and configuration files Object form shall mean any form resulting from mechanical transformation or translation of a Source including but not limited to compiled object generated and conversions to other media types Work shall mean the work of whether in Source or Object made available under the as indicated by a copyright notice that is included in or attached to the whether in Source or Object that is based or other modifications as a an original work of authorship For the purposes of this Derivative Works shall not include works that remain separable or merely the Work and Derivative Works thereof Contribution shall mean any work of including the original version of the Work and any modifications or additions to that Work or Derivative Works that is intentionally submitted to Licensor for inclusion in the Work by the copyright owner or by an individual or Legal Entity authorized to submit on behalf of the copyright owner For the purposes of this submitted means any form of or written communication sent to the Licensor or its including but not limited to communication on electronic mailing source code control and issue tracking systems that are managed by
Apache License January AND DISTRIBUTION Definitions License shall mean the terms and conditions for and distribution as defined by Sections through of this document Licensor shall mean the copyright owner or entity authorized by the copyright owner that is granting the License Legal Entity shall mean the union of the acting entity and all other entities that control are controlled by or are under common control with that entity For the purposes of this definition control direct or to cause the direction or management of such whether by contract or including but not limited to software source documentation and configuration files Object form shall mean any form resulting from mechanical transformation or translation of a Source including but not limited to compiled object generated and conversions to other media types Work shall mean the work of whether in Source or Object made available under the as indicated by a copyright notice that is included in or attached to the whether in Source or Object that is based or other modifications as a an original work of authorship For the purposes of this Derivative Works shall not include works that remain separable or merely the Work and Derivative Works thereof Contribution shall mean any work of including the original version of the Work and any modifications or additions to that Work or Derivative Works that is intentionally submitted to Licensor for inclusion in the Work by the copyright owner or by an individual or Legal Entity authorized to submit on behalf of the copyright owner For the purposes of this submitted means any form of or written communication sent to the Licensor or its including but not limited to communication on electronic mailing source code control and issue tracking systems that are managed or on behalf the Licensor for the purpose of discussing and improving the but excluding communication that is conspicuously marked or otherwise designated in writing by the copyright owner as Not a Contribution Contributor shall mean Licensor and any individual or Legal Entity on behalf of whom a Contribution has been received by Licensor and subsequently incorporated within the Work Grant of Copyright License Subject to the terms and conditions of this each Contributor hereby grants to You a non no royalty irrevocable copyright license to prepare Derivative Works publicly publicly and distribute the Work and such Derivative Works in Source or Object form Grant of Patent License Subject to the terms and conditions of this each Contributor hereby grants to You a non no royalty have made
static configuration should be added through ResourceLoaderGetConfigVars instead can be used to get the real title after the basic globals have been set up
Definition: hooks.txt:2163
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
RedisConnRef $conn
string $slot
Pool slot value.
string $session
Unique string to identify this process.
this hook is for auditing only RecentChangesLinked and Watchlist RecentChangesLinked and Watchlist e g Watchlist removed from all revisions and log entries to which it was applied This gives extensions a chance to take it off their books as the deletion has already been partly carried out by this point or something similar the user will be unable to create the tag set and then return false from the hook function Ensure you consume the ChangeTagAfterDelete hook to carry out custom deletion actions as context called by AbstractContent::getParserOutput May be used to override the normal model specific rendering of page content as context as context the output can only depend on parameters provided to this hook not on global state indicating whether full HTML should be generated If generation of HTML may be but other information should still be present in the ParserOutput object to manipulate or replace but no entry for that model exists in $wgContentHandlers if desired 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 inclusive false for true for descending in case the handler function wants to provide a converted Content object Note that $result getContentModel() must return $toModel. 'CustomEditor'$rcid is used in generating this variable which contains information about the new such as the revision s whether the revision was marked as a minor edit or not
Definition: hooks.txt:1160
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 QUEUE_FULL
Definition: PoolCounter.php:53
Helper class to handle automatically marking connectons as reusable (via RAII pattern) ...
this hook is for auditing only RecentChangesLinked and Watchlist RecentChangesLinked and Watchlist e g Watchlist removed from all revisions and log entries to which it was applied This gives extensions a chance to take it off their books as the deletion has already been partly carried out by this point or something similar the user will be unable to create the tag set $status
Definition: hooks.txt:1050
When you have many workers (threads/servers) giving service, and a cached item expensive to produce e...
Definition: PoolCounter.php:45
this class mediates it Skin Encapsulates a look and feel for the wiki All of the functions that render HTML and make choices about how to render it are here and are called from various other places when needed(most notably, OutputPage::addWikiText()).The StandardSkin object is a complete implementation
We ve cleaned up the code here by removing clumps of infrequently used code and moving them off somewhere else It s much easier for someone working with this code to see what s _really_ going on
Definition: hooks.txt:86
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 which defines all default service and specifies how they depend on each other("wiring").When a new service is added to MediaWiki core
Apache License January AND DISTRIBUTION Definitions License shall mean the terms and conditions for and distribution as defined by Sections through of this document Licensor shall mean the copyright owner or entity authorized by the copyright owner that is granting the License Legal Entity shall mean the union of the acting entity and all other entities that control are controlled by or are under common control with that entity For the purposes of this definition control direct or to cause the direction or management of such whether by contract or including but not limited to software source documentation and configuration files Object form shall mean any form resulting from mechanical transformation or translation of a Source including but not limited to compiled object generated and conversions to other media types Work shall mean the work of whether in Source or Object made available under the as indicated by a copyright notice that is included in or attached to the work(an example is provided in the Appendix below)."Derivative Works"shall mean any work
const TIMEOUT
Definition: PoolCounter.php:54
</td >< td > &</td >< td > t want your writing to be edited mercilessly and redistributed at will
=Architecture==Two class hierarchies are used to provide the functionality associated with the different content models:*Content interface(and AbstractContent base class) define functionality that acts on the concrete content of a page, and *ContentHandler base class provides functionality specific to a content model, but not acting on concrete content.The most important function of ContentHandler is to act as a factory for the appropriate implementation of Content.These Content objects are to be used by MediaWiki everywhere, instead of passing page content around as text.All manipulation and analysis of page content must be done via the appropriate methods of the Content object.For each content model, a subclass of ContentHandler has to be registered with $wgContentHandlers.The ContentHandler object for a given content model can be obtained using ContentHandler::getForModelID($id).Also Title, WikiPage and Revision now have getContentHandler() methods for convenience.ContentHandler objects are singletons that provide functionality specific to the content type, but not directly acting on the content of some page.ContentHandler::makeEmptyContent() and ContentHandler::unserializeContent() can be used to create a Content object of the appropriate type.However, it is recommended to instead use WikiPage::getContent() resp.Revision::getContent() to get a page's content as a Content object.These two methods should be the ONLY way in which page content is accessed.Another important function of ContentHandler objects is to define custom action handlers for a content model, see ContentHandler::getActionOverrides().This is similar to what WikiPage::getActionOverrides() was already doing.==Serialization==With the ContentHandler facility, page content no longer has to be text based.Objects implementing the Content interface are used to represent and handle the content internally.For storage and data exchange, each content model supports at least one serialization format via ContentHandler::serializeContent($content).The list of supported formats for a given content model can be accessed using ContentHandler::getSupportedFormats().Content serialization formats are identified using MIME type like strings.The following formats are built in:*text/x-wiki-wikitext *text/javascript-for js pages *text/css-for css pages *text/plain-for future use, e.g.with plain text messages.*text/html-for future use, e.g.with plain html messages.*application/vnd.php.serialized-for future use with the api and for extensions *application/json-for future use with the api, and for use by extensions *application/xml-for future use with the api, and for use by extensions In PHP, use the corresponding CONTENT_FORMAT_XXX constant.Note that when using the API to access page content, especially action=edit, action=parse and action=query &prop=revisions, the model and format of the content should always be handled explicitly.Without that information, interpretation of the provided content is not reliable.The same applies to XML dumps generated via maintenance/dumpBackup.php or Special:Export.Also note that the API will provide encapsulated, serialized content-so if the API was called with format=json, and contentformat is also json(or rather, application/json), the page content is represented as a string containing an escaped json structure.Extensions that use JSON to serialize some types of page content may provide specialized API modules that allow access to that content in a more natural form.==Compatibility==The ContentHandler facility is introduced in a way that should allow all existing code to keep functioning at least for pages that contain wikitext or other text based content.However, a number of functions and hooks have been deprecated in favor of new versions that are aware of the page's content model, and will now generate warnings when used.Most importantly, the following functions have been deprecated:*Revisions::getText() is deprecated in favor Revisions::getContent()*WikiPage::getText() is deprecated in favor WikiPage::getContent() Also, the old Article::getContent()(which returns text) is superceded by Article::getContentObject().However, both methods should be avoided since they do not provide clean access to the page's actual content.For instance, they may return a system message for non-existing pages.Use WikiPage::getContent() instead.Code that relies on a textual representation of the page content should eventually be rewritten.However, ContentHandler::getContentText() provides a stop-gap that can be used to get text for a page.Its behavior is controlled by $wgContentHandlerTextFallback it
skin txt MediaWiki includes four core it has been set as the default in MediaWiki since the replacing Monobook it had been the default skin since then
Definition: skin.txt:10
onAcquire()
Update any lock tracking information when the lock is acquired.
initAndPopPoolSlotList(RedisConnRef $conn, $now)
do that in ParserLimitReportFormat instead use this to modify the parameters of the image and a DIV can begin in one section and end in another Make sure your code can handle that case gracefully See the EditSectionClearerLink extension for an example zero but section is usually empty its values are the globals values before the output is cached one of or reset my talk my contributions etc etc otherwise the built in rate limiting checks are if enabled allows for interception of redirect as a string mapping parameter names to values & $type
Definition: hooks.txt:2495
const RELEASED
Definition: PoolCounter.php:48
const LOCK_HELD
Definition: PoolCounter.php:55
Apache License January AND DISTRIBUTION Definitions License shall mean the terms and conditions for and distribution as defined by Sections through of this document Licensor shall mean the copyright owner or entity authorized by the copyright owner that is granting the License Legal Entity shall mean the union of the acting entity and all other entities that control are controlled by or are under common control with that entity For the purposes of this definition control direct or to cause the direction or management of such whether by contract or including but not limited to software source documentation and configuration files Object form shall mean any form resulting from mechanical transformation or translation of a Source including but not limited to compiled object generated and conversions to other media types Work shall mean the work of whether in Source or Object made available under the as indicated by a copyright notice that is included in or attached to the whether in Source or Object that is based or other modifications as a an original work of authorship For the purposes of this Derivative Works shall not include works that remain separable or merely the Work and Derivative Works thereof Contribution shall mean any work of including the original version of the Work and any modifications or additions to that Work or Derivative Works that is intentionally submitted to Licensor for inclusion in the Work by the copyright owner or by an individual or Legal Entity authorized to submit on behalf of the copyright owner For the purposes of this submitted means any form of or written communication sent to the Licensor or its including but not limited to communication on electronic mailing source code control and issue tracking systems that are managed or on behalf the Licensor for the purpose of discussing and improving the but excluding communication that is conspicuously marked or otherwise designated in writing by the copyright owner as Not a Contribution Contributor shall mean Licensor and any individual or Legal Entity on behalf of whom a Contribution has been received by Licensor and subsequently incorporated within the Work Grant of Copyright License Subject to the terms and conditions of this each Contributor hereby grants to You a non no royalty free
static releaseAll()
Try to make sure that locks get released (even with exceptions and fatals)
registerAcquisitionTime(RedisConnRef $conn, $slot, $now)