includes/filerepo/backend/FileBackendMultiWrite.php

   1 <?php
   2 /**
   3  * Proxy backend that mirrors writes to several internal backends.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @file
  21  * @ingroup FileBackend
  22  * @author Aaron Schulz
  23  */
  24
  25 /**
  26  * @brief Proxy backend that mirrors writes to several internal backends.
  27  *
  28  * This class defines a multi-write backend. Multiple backends can be
  29  * registered to this proxy backend and it will act as a single backend.
  30  * Use this when all access to those backends is through this proxy backend.
  31  * At least one of the backends must be declared the "master" backend.
  32  *
  33  * Only use this class when transitioning from one storage system to another.
  34  *
  35  * Read operations are only done on the 'master' backend for consistency.
  36  * Write operations are performed on all backends, in the order defined.
  37  * If an operation fails on one backend it will be rolled back from the others.
  38  *
  39  * @ingroup FileBackend
  40  * @since 1.19
  41  */
  42 class FileBackendMultiWrite extends FileBackend {
  43         /** @var Array Prioritized list of FileBackendStore objects */
  44         protected $backends = array(); // array of (backend index => backends)
  45         protected $masterIndex = -1; // integer; index of master backend
  46         protected $syncChecks = 0; // integer bitfield
  47
  48         /* Possible internal backend consistency checks */
  49         const CHECK_SIZE = 1;
  50         const CHECK_TIME = 2;
  51         const CHECK_SHA1 = 4;
  52
  53         /**
  54          * Construct a proxy backend that consists of several internal backends.
  55          * Locking, journaling, and read-only checks are handled by the proxy backend.
  56          *
  57          * Additional $config params include:
  58          *   - backends   : Array of backend config and multi-backend settings.
  59          *                  Each value is the config used in the constructor of a
  60          *                  FileBackendStore class, but with these additional settings:
  61          *                    - class         : The name of the backend class
  62          *                    - isMultiMaster : This must be set for one backend.
  63          *                    - template:     : If given a backend name, this will use
  64          *                                      the config of that backend as a template.
  65          *                                      Values specified here take precedence.
  66          *   - syncChecks : Integer bitfield of internal backend sync checks to perform.
  67          *                  Possible bits include the FileBackendMultiWrite::CHECK_* constants.
  68          *                  There are constants for SIZE, TIME, and SHA1.
  69          *                  The checks are done before allowing any file operations.
  70          * @param $config Array
  71          * @throws MWException
  72          */
  73         public function __construct( array $config ) {
  74                 parent::__construct( $config );
  75                 $namesUsed = array();
  76                 // Construct backends here rather than via registration
  77                 // to keep these backends hidden from outside the proxy.
  78                 foreach ( $config['backends'] as $index => $config ) {
  79                         if ( isset( $config['template'] ) ) {
  80                                 // Config is just a modified version of a registered backend's.
  81                                 // This should only be used when that config is used only by this backend.
  82                                 $config = $config + FileBackendGroup::singleton()->config( $config['template'] );
  83                         }
  84                         $name = $config['name'];
  85                         if ( isset( $namesUsed[$name] ) ) { // don't break FileOp predicates
  86                                 throw new MWException( "Two or more backends defined with the name $name." );
  87                         }
  88                         $namesUsed[$name] = 1;
  89                         // Alter certain sub-backend settings for sanity
  90                         unset( $config['readOnly'] ); // use proxy backend setting
  91                         unset( $config['fileJournal'] ); // use proxy backend journal
  92                         $config['wikiId'] = $this->wikiId; // use the proxy backend wiki ID
  93                         $config['lockManager'] = 'nullLockManager'; // lock under proxy backend
  94                         if ( !empty( $config['isMultiMaster'] ) ) {
  95                                 if ( $this->masterIndex >= 0 ) {
  96                                         throw new MWException( 'More than one master backend defined.' );
  97                                 }
  98                                 $this->masterIndex = $index; // this is the "master"
  99                                 $config['fileJournal'] = $this->fileJournal; // log under proxy backend
 100                         }
 101                         // Create sub-backend object
 102                         if ( !isset( $config['class'] ) ) {
 103                                 throw new MWException( 'No class given for a backend config.' );
 104                         }
 105                         $class = $config['class'];
 106                         $this->backends[$index] = new $class( $config );
 107                 }
 108                 if ( $this->masterIndex < 0 ) { // need backends and must have a master
 109                         throw new MWException( 'No master backend defined.' );
 110                 }
 111                 $this->syncChecks = isset( $config['syncChecks'] )
 112                         ? $config['syncChecks']
 113                         : self::CHECK_SIZE;
 114         }
 115
 116         /**
 117          * @see FileBackend::doOperationsInternal()
 118          * @return Status
 119          */
 120         final protected function doOperationsInternal( array $ops, array $opts ) {
 121                 $status = Status::newGood();
 122
 123                 $mbe = $this->backends[$this->masterIndex]; // convenience
 124
 125                 // Get the paths to lock from the master backend
 126                 $realOps = $this->substOpBatchPaths( $ops, $mbe );
 127                 $paths = $mbe->getPathsToLockForOpsInternal( $mbe->getOperationsInternal( $realOps ) );
 128                 // Get the paths under the proxy backend's name
 129                 $paths['sh'] = $this->unsubstPaths( $paths['sh'] );
 130                 $paths['ex'] = $this->unsubstPaths( $paths['ex'] );
 131                 // Try to lock those files for the scope of this function...
 132                 if ( empty( $opts['nonLocking'] ) ) {
 133                         // Try to lock those files for the scope of this function...
 134                         $scopeLockS = $this->getScopedFileLocks( $paths['sh'], LockManager::LOCK_UW, $status );
 135                         $scopeLockE = $this->getScopedFileLocks( $paths['ex'], LockManager::LOCK_EX, $status );
 136                         if ( !$status->isOK() ) {
 137                                 return $status; // abort
 138                         }
 139                 }
 140                 // Clear any cache entries (after locks acquired)
 141                 $this->clearCache();
 142                 // Do a consistency check to see if the backends agree
 143                 $status->merge( $this->consistencyCheck( array_merge( $paths['sh'], $paths['ex'] ) ) );
 144                 if ( !$status->isOK() ) {
 145                         return $status; // abort
 146                 }
 147                 // Actually attempt the operation batch on the master backend...
 148                 $masterStatus = $mbe->doOperations( $realOps, $opts );
 149                 $status->merge( $masterStatus );
 150                 // Propagate the operations to the clone backends...
 151                 foreach ( $this->backends as $index => $backend ) {
 152                         if ( $index !== $this->masterIndex ) { // not done already
 153                                 $realOps = $this->substOpBatchPaths( $ops, $backend );
 154                                 $status->merge( $backend->doOperations( $realOps, $opts ) );
 155                         }
 156                 }
 157                 // Make 'success', 'successCount', and 'failCount' fields reflect
 158                 // the overall operation, rather than all the batches for each backend.
 159                 // Do this by only using success values from the master backend's batch.
 160                 $status->success = $masterStatus->success;
 161                 $status->successCount = $masterStatus->successCount;
 162                 $status->failCount = $masterStatus->failCount;
 163
 164                 return $status;
 165         }
 166
 167         /**
 168          * Check that a set of files are consistent across all internal backends
 169          *
 170          * @param $paths Array
 171          * @return Status
 172          */
 173         public function consistencyCheck( array $paths ) {
 174                 $status = Status::newGood();
 175                 if ( $this->syncChecks == 0 || count( $this->backends ) <= 1 ) {
 176                         return $status; // skip checks
 177                 }
 178
 179                 $mBackend = $this->backends[$this->masterIndex];
 180                 foreach ( array_unique( $paths ) as $path ) {
 181                         $params = array( 'src' => $path, 'latest' => true );
 182                         $mParams = $this->substOpPaths( $params, $mBackend );
 183                         // Stat the file on the 'master' backend
 184                         $mStat = $mBackend->getFileStat( $mParams );
 185                         if ( $this->syncChecks & self::CHECK_SHA1 ) {
 186                                 $mSha1 = $mBackend->getFileSha1( $mParams );
 187                         } else {
 188                                 $mSha1 = false;
 189                         }
 190                         $mUsable = $mBackend->isPathUsableInternal( $mParams['src'] );
 191                         // Check of all clone backends agree with the master...
 192                         foreach ( $this->backends as $index => $cBackend ) {
 193                                 if ( $index === $this->masterIndex ) {
 194                                         continue; // master
 195                                 }
 196                                 $cParams = $this->substOpPaths( $params, $cBackend );
 197                                 $cStat = $cBackend->getFileStat( $cParams );
 198                                 if ( $mStat ) { // file is in master
 199                                         if ( !$cStat ) { // file should exist
 200                                                 $status->fatal( 'backend-fail-synced', $path );
 201                                                 continue;
 202                                         }
 203                                         if ( $this->syncChecks & self::CHECK_SIZE ) {
 204                                                 if ( $cStat['size'] != $mStat['size'] ) { // wrong size
 205                                                         $status->fatal( 'backend-fail-synced', $path );
 206                                                         continue;
 207                                                 }
 208                                         }
 209                                         if ( $this->syncChecks & self::CHECK_TIME ) {
 210                                                 $mTs = wfTimestamp( TS_UNIX, $mStat['mtime'] );
 211                                                 $cTs = wfTimestamp( TS_UNIX, $cStat['mtime'] );
 212                                                 if ( abs( $mTs - $cTs ) > 30 ) { // outdated file somewhere
 213                                                         $status->fatal( 'backend-fail-synced', $path );
 214                                                         continue;
 215                                                 }
 216                                         }
 217                                         if ( $this->syncChecks & self::CHECK_SHA1 ) {
 218                                                 if ( $cBackend->getFileSha1( $cParams ) !== $mSha1 ) { // wrong SHA1
 219                                                         $status->fatal( 'backend-fail-synced', $path );
 220                                                         continue;
 221                                                 }
 222                                         }
 223                                 } else { // file is not in master
 224                                         if ( $cStat ) { // file should not exist
 225                                                 $status->fatal( 'backend-fail-synced', $path );
 226                                         }
 227                                 }
 228                                 if ( $mUsable !== $cBackend->isPathUsableInternal( $cParams['src'] ) ) {
 229                                         $status->fatal( 'backend-fail-synced', $path );
 230                                 }
 231                         }
 232                 }
 233
 234                 return $status;
 235         }
 236
 237         /**
 238          * Substitute the backend name in storage path parameters
 239          * for a set of operations with that of a given internal backend.
 240          *
 241          * @param $ops Array List of file operation arrays
 242          * @param $backend FileBackendStore
 243          * @return Array
 244          */
 245         protected function substOpBatchPaths( array $ops, FileBackendStore $backend ) {
 246                 $newOps = array(); // operations
 247                 foreach ( $ops as $op ) {
 248                         $newOp = $op; // operation
 249                         foreach ( array( 'src', 'srcs', 'dst', 'dir' ) as $par ) {
 250                                 if ( isset( $newOp[$par] ) ) { // string or array
 251                                         $newOp[$par] = $this->substPaths( $newOp[$par], $backend );
 252                                 }
 253                         }
 254                         $newOps[] = $newOp;
 255                 }
 256                 return $newOps;
 257         }
 258
 259         /**
 260          * Same as substOpBatchPaths() but for a single operation
 261          *
 262          * @param $ops array File operation array
 263          * @param $backend FileBackendStore
 264          * @return Array
 265          */
 266         protected function substOpPaths( array $ops, FileBackendStore $backend ) {
 267                 $newOps = $this->substOpBatchPaths( array( $ops ), $backend );
 268                 return $newOps[0];
 269         }
 270
 271         /**
 272          * Substitute the backend of storage paths with an internal backend's name
 273          *
 274          * @param $paths Array|string List of paths or single string path
 275          * @param $backend FileBackendStore
 276          * @return Array|string
 277          */
 278         protected function substPaths( $paths, FileBackendStore $backend ) {
 279                 return preg_replace(
 280                         '!^mwstore://' . preg_quote( $this->name ) . '/!',
 281                         StringUtils::escapeRegexReplacement( "mwstore://{$backend->getName()}/" ),
 282                         $paths // string or array
 283                 );
 284         }
 285
 286         /**
 287          * Substitute the backend of internal storage paths with the proxy backend's name
 288          *
 289          * @param $paths Array|string List of paths or single string path
 290          * @return Array|string
 291          */
 292         protected function unsubstPaths( $paths ) {
 293                 return preg_replace(
 294                         '!^mwstore://([^/]+)!',
 295                         StringUtils::escapeRegexReplacement( "mwstore://{$this->name}" ),
 296                         $paths // string or array
 297                 );
 298         }
 299
 300         /**
 301          * @see FileBackend::doQuickOperationsInternal()
 302          * @return Status
 303          */
 304         protected function doQuickOperationsInternal( array $ops ) {
 305                 $status = Status::newGood();
 306                 // Do the operations on the master backend; setting Status fields...
 307                 $realOps = $this->substOpBatchPaths( $ops, $this->backends[$this->masterIndex] );
 308                 $masterStatus = $this->backends[$this->masterIndex]->doQuickOperations( $realOps );
 309                 $status->merge( $masterStatus );
 310                 // Propagate the operations to the clone backends...
 311                 foreach ( $this->backends as $index => $backend ) {
 312                         if ( $index !== $this->masterIndex ) { // not done already
 313                                 $realOps = $this->substOpBatchPaths( $ops, $backend );
 314                                 $status->merge( $backend->doQuickOperations( $realOps ) );
 315                         }
 316                 }
 317                 // Make 'success', 'successCount', and 'failCount' fields reflect
 318                 // the overall operation, rather than all the batches for each backend.
 319                 // Do this by only using success values from the master backend's batch.
 320                 $status->success = $masterStatus->success;
 321                 $status->successCount = $masterStatus->successCount;
 322                 $status->failCount = $masterStatus->failCount;
 323                 return $status;
 324         }
 325
 326         /**
 327          * @see FileBackend::doPrepare()
 328          * @return Status
 329          */
 330         protected function doPrepare( array $params ) {
 331                 $status = Status::newGood();
 332                 foreach ( $this->backends as $backend ) {
 333                         $realParams = $this->substOpPaths( $params, $backend );
 334                         $status->merge( $backend->doPrepare( $realParams ) );
 335                 }
 336                 return $status;
 337         }
 338
 339         /**
 340          * @see FileBackend::doSecure()
 341          * @param $params array
 342          * @return Status
 343          */
 344         protected function doSecure( array $params ) {
 345                 $status = Status::newGood();
 346                 foreach ( $this->backends as $backend ) {
 347                         $realParams = $this->substOpPaths( $params, $backend );
 348                         $status->merge( $backend->doSecure( $realParams ) );
 349                 }
 350                 return $status;
 351         }
 352
 353         /**
 354          * @see FileBackend::doPublish()
 355          * @param $params array
 356          * @return Status
 357          */
 358         protected function doPublish( array $params ) {
 359                 $status = Status::newGood();
 360                 foreach ( $this->backends as $backend ) {
 361                         $realParams = $this->substOpPaths( $params, $backend );
 362                         $status->merge( $backend->doPublish( $realParams ) );
 363                 }
 364                 return $status;
 365         }
 366
 367         /**
 368          * @see FileBackend::doClean()
 369          * @param $params array
 370          * @return Status
 371          */
 372         protected function doClean( array $params ) {
 373                 $status = Status::newGood();
 374                 foreach ( $this->backends as $backend ) {
 375                         $realParams = $this->substOpPaths( $params, $backend );
 376                         $status->merge( $backend->doClean( $realParams ) );
 377                 }
 378                 return $status;
 379         }
 380
 381         /**
 382          * @see FileBackend::concatenate()
 383          * @param $params array
 384          * @return Status
 385          */
 386         public function concatenate( array $params ) {
 387                 // We are writing to an FS file, so we don't need to do this per-backend
 388                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 389                 return $this->backends[$this->masterIndex]->concatenate( $realParams );
 390         }
 391
 392         /**
 393          * @see FileBackend::fileExists()
 394          * @param $params array
 395          */
 396         public function fileExists( array $params ) {
 397                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 398                 return $this->backends[$this->masterIndex]->fileExists( $realParams );
 399         }
 400
 401         /**
 402          * @see FileBackend::getFileTimestamp()
 403          * @param $params array
 404          * @return bool|string
 405          */
 406         public function getFileTimestamp( array $params ) {
 407                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 408                 return $this->backends[$this->masterIndex]->getFileTimestamp( $realParams );
 409         }
 410
 411         /**
 412          * @see FileBackend::getFileSize()
 413          * @param $params array
 414          * @return bool|int
 415          */
 416         public function getFileSize( array $params ) {
 417                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 418                 return $this->backends[$this->masterIndex]->getFileSize( $realParams );
 419         }
 420
 421         /**
 422          * @see FileBackend::getFileStat()
 423          * @param $params array
 424          * @return Array|bool|null
 425          */
 426         public function getFileStat( array $params ) {
 427                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 428                 return $this->backends[$this->masterIndex]->getFileStat( $realParams );
 429         }
 430
 431         /**
 432          * @see FileBackend::getFileContents()
 433          * @param $params array
 434          * @return bool|string
 435          */
 436         public function getFileContents( array $params ) {
 437                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 438                 return $this->backends[$this->masterIndex]->getFileContents( $realParams );
 439         }
 440
 441         /**
 442          * @see FileBackend::getFileSha1Base36()
 443          * @param $params array
 444          * @return bool|string
 445          */
 446         public function getFileSha1Base36( array $params ) {
 447                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 448                 return $this->backends[$this->masterIndex]->getFileSha1Base36( $realParams );
 449         }
 450
 451         /**
 452          * @see FileBackend::getFileProps()
 453          * @param $params array
 454          * @return Array
 455          */
 456         public function getFileProps( array $params ) {
 457                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 458                 return $this->backends[$this->masterIndex]->getFileProps( $realParams );
 459         }
 460
 461         /**
 462          * @see FileBackend::streamFile()
 463          * @param $params array
 464          * @return \Status
 465          */
 466         public function streamFile( array $params ) {
 467                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 468                 return $this->backends[$this->masterIndex]->streamFile( $realParams );
 469         }
 470
 471         /**
 472          * @see FileBackend::getLocalReference()
 473          * @param $params array
 474          * @return FSFile|null
 475          */
 476         public function getLocalReference( array $params ) {
 477                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 478                 return $this->backends[$this->masterIndex]->getLocalReference( $realParams );
 479         }
 480
 481         /**
 482          * @see FileBackend::getLocalCopy()
 483          * @param $params array
 484          * @return null|TempFSFile
 485          */
 486         public function getLocalCopy( array $params ) {
 487                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 488                 return $this->backends[$this->masterIndex]->getLocalCopy( $realParams );
 489         }
 490
 491         /**
 492          * @see FileBackend::directoryExists()
 493          * @param $params array
 494          * @return bool|null
 495          */
 496         public function directoryExists( array $params ) {
 497                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 498                 return $this->backends[$this->masterIndex]->directoryExists( $realParams );
 499         }
 500
 501         /**
 502          * @see FileBackend::getSubdirectoryList()
 503          * @param $params array
 504          * @return Array|null|Traversable
 505          */
 506         public function getDirectoryList( array $params ) {
 507                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 508                 return $this->backends[$this->masterIndex]->getDirectoryList( $realParams );
 509         }
 510
 511         /**
 512          * @see FileBackend::getFileList()
 513          * @param $params array
 514          * @return Array|null|\Traversable
 515          */
 516         public function getFileList( array $params ) {
 517                 $realParams = $this->substOpPaths( $params, $this->backends[$this->masterIndex] );
 518                 return $this->backends[$this->masterIndex]->getFileList( $realParams );
 519         }
 520
 521         /**
 522          * @see FileBackend::clearCache()
 523          */
 524         public function clearCache( array $paths = null ) {
 525                 foreach ( $this->backends as $backend ) {
 526                         $realPaths = is_array( $paths ) ? $this->substPaths( $paths, $backend ) : null;
 527                         $backend->clearCache( $realPaths );
 528                 }
 529         }
 530
 531         /**
 532          * @see FileBackend::getScopedLocksForOps()
 533          */
 534         public function getScopedLocksForOps( array $ops, Status $status ) {
 535                 $fileOps = $this->backends[$this->masterIndex]->getOperationsInternal( $ops );
 536                 // Get the paths to lock from the master backend
 537                 $paths = $this->backends[$this->masterIndex]->getPathsToLockForOpsInternal( $fileOps );
 538                 // Get the paths under the proxy backend's name
 539                 $paths['sh'] = $this->unsubstPaths( $paths['sh'] );
 540                 $paths['ex'] = $this->unsubstPaths( $paths['ex'] );
 541                 return array(
 542                         $this->getScopedFileLocks( $paths['sh'], LockManager::LOCK_UW, $status ),
 543                         $this->getScopedFileLocks( $paths['ex'], LockManager::LOCK_EX, $status )
 544                 );
 545         }
 546 }