MediaWiki  1.28.0
MultiWriteBagOStuff.php
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1 <?php
33  protected $caches;
35  protected $asyncWrites = false;
36 
38  const ALL = INF;
39 
40  const UPGRADE_TTL = 3600; // TTL when a key is copied to a higher cache tier
41 
62  public function __construct( $params ) {
63  parent::__construct( $params );
64 
65  if ( empty( $params['caches'] ) || !is_array( $params['caches'] ) ) {
66  throw new InvalidArgumentException(
67  __METHOD__ . ': "caches" parameter must be an array of caches'
68  );
69  }
70 
71  $this->caches = [];
72  foreach ( $params['caches'] as $cacheInfo ) {
73  if ( $cacheInfo instanceof BagOStuff ) {
74  $this->caches[] = $cacheInfo;
75  } else {
76  if ( !isset( $cacheInfo['args'] ) ) {
77  // B/C for when $cacheInfo was for ObjectCache::newFromParams().
78  // Callers intenting this to be for ObjectFactory::getObjectFromSpec
79  // should have set "args" per the docs above. Doings so avoids extra
80  // (likely harmless) params (factory/class/calls) ending up in "args".
81  $cacheInfo['args'] = [ $cacheInfo ];
82  }
83  $this->caches[] = ObjectFactory::getObjectFromSpec( $cacheInfo );
84  }
85  }
86  $this->mergeFlagMaps( $this->caches );
87 
88  $this->asyncWrites = (
89  isset( $params['replication'] ) &&
90  $params['replication'] === 'async' &&
91  is_callable( $this->asyncHandler )
92  );
93  }
94 
95  public function setDebug( $debug ) {
96  foreach ( $this->caches as $cache ) {
97  $cache->setDebug( $debug );
98  }
99  }
100 
101  protected function doGet( $key, $flags = 0 ) {
102  if ( ( $flags & self::READ_LATEST ) == self::READ_LATEST ) {
103  // If the latest write was a delete(), we do NOT want to fallback
104  // to the other tiers and possibly see the old value. Also, this
105  // is used by mergeViaLock(), which only needs to hit the primary.
106  return $this->caches[0]->get( $key, $flags );
107  }
108 
109  $misses = 0; // number backends checked
110  $value = false;
111  foreach ( $this->caches as $cache ) {
112  $value = $cache->get( $key, $flags );
113  if ( $value !== false ) {
114  break;
115  }
116  ++$misses;
117  }
118 
119  if ( $value !== false
120  && $misses > 0
121  && ( $flags & self::READ_VERIFIED ) == self::READ_VERIFIED
122  ) {
123  $this->doWrite( $misses, $this->asyncWrites, 'set', $key, $value, self::UPGRADE_TTL );
124  }
125 
126  return $value;
127  }
128 
129  public function set( $key, $value, $exptime = 0, $flags = 0 ) {
130  $asyncWrites = ( ( $flags & self::WRITE_SYNC ) == self::WRITE_SYNC )
131  ? false
133 
134  return $this->doWrite( self::ALL, $asyncWrites, 'set', $key, $value, $exptime );
135  }
136 
137  public function delete( $key ) {
138  return $this->doWrite( self::ALL, $this->asyncWrites, 'delete', $key );
139  }
140 
141  public function add( $key, $value, $exptime = 0 ) {
142  return $this->doWrite( self::ALL, $this->asyncWrites, 'add', $key, $value, $exptime );
143  }
144 
145  public function incr( $key, $value = 1 ) {
146  return $this->doWrite( self::ALL, $this->asyncWrites, 'incr', $key, $value );
147  }
148 
149  public function decr( $key, $value = 1 ) {
150  return $this->doWrite( self::ALL, $this->asyncWrites, 'decr', $key, $value );
151  }
152 
153  public function lock( $key, $timeout = 6, $expiry = 6, $rclass = '' ) {
154  // Only need to lock the first cache; also avoids deadlocks
155  return $this->caches[0]->lock( $key, $timeout, $expiry, $rclass );
156  }
157 
158  public function unlock( $key ) {
159  // Only the first cache is locked
160  return $this->caches[0]->unlock( $key );
161  }
162 
163  public function getLastError() {
164  return $this->caches[0]->getLastError();
165  }
166 
167  public function clearLastError() {
168  $this->caches[0]->clearLastError();
169  }
170 
180  protected function doWrite( $count, $asyncWrites, $method /*, ... */ ) {
181  $ret = true;
182  $args = array_slice( func_get_args(), 3 );
183 
184  foreach ( $this->caches as $i => $cache ) {
185  if ( $i >= $count ) {
186  break; // ignore the lower tiers
187  }
188 
189  if ( $i == 0 || !$asyncWrites ) {
190  // First store or in sync mode: write now and get result
191  if ( !call_user_func_array( [ $cache, $method ], $args ) ) {
192  $ret = false;
193  }
194  } else {
195  // Secondary write in async mode: do not block this HTTP request
197  call_user_func(
198  $this->asyncHandler,
199  function () use ( $cache, $method, $args, $logger ) {
200  if ( !call_user_func_array( [ $cache, $method ], $args ) ) {
201  $logger->warning( "Async $method op failed" );
202  }
203  }
204  );
205  }
206  }
207 
208  return $ret;
209  }
210 
219  public function deleteObjectsExpiringBefore( $date, $progressCallback = false ) {
220  $ret = false;
221  foreach ( $this->caches as $cache ) {
222  if ( $cache->deleteObjectsExpiringBefore( $date, $progressCallback ) ) {
223  $ret = true;
224  }
225  }
226 
227  return $ret;
228  }
229 }
static getObjectFromSpec($spec)
Instantiate an object based on a specification array.
null means default in associative array with keys and values unescaped Should be merged with default with a value of false meaning to suppress the attribute in associative array with keys and values unescaped noclasses & $ret
Definition: hooks.txt:1936
doWrite($count, $asyncWrites, $method)
Apply a write method to the first $count backing caches.
Apache License January AND DISTRIBUTION Definitions License shall mean the terms and conditions for use
add($key, $value, $exptime=0)
$value
it s the revision text itself In either if gzip is the revision text is gzipped $flags
Definition: hooks.txt:2703
if($line===false) $args
Definition: cdb.php:64
const ALL
Idiom for "write to all backends".
__construct($params)
$params include:
A cache class that replicates all writes to multiple child caches.
bool $asyncWrites
Use async secondary writes.
lock($key, $timeout=6, $expiry=6, $rclass= '')
$cache
Definition: mcc.php:33
$params
mergeFlagMaps(array $bags)
Merge the flag maps of one or more BagOStuff objects into a "lowest common denominator" map...
Definition: BagOStuff.php:783
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 $wgServiceWiringFiles lists includes ServiceWiring php
Definition: injection.txt:35
deleteObjectsExpiringBefore($date, $progressCallback=false)
Delete objects expiring before a certain date.
LoggerInterface $logger
Definition: BagOStuff.php:55
$count
set($key, $value, $exptime=0, $flags=0)
$debug
Definition: mcc.php:31