3 * Proxy backend that mirrors writes to several internal backends.
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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.
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.
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
21 * @ingroup FileBackend
22 * @author Aaron Schulz
26 * @brief Proxy backend that mirrors writes to several internal backends.
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.
33 * Only use this class when transitioning from one storage system to another.
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.
39 * @ingroup FileBackend
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
48 protected $noPushDirConts = array();
49 protected $noPushQuickOps = false; // boolean
51 /* Possible internal backend consistency checks */
57 * Construct a proxy backend that consists of several internal backends.
58 * Locking, journaling, and read-only checks are handled by the proxy backend.
60 * Additional $config params include:
61 * - backends : Array of backend config and multi-backend settings.
62 * Each value is the config used in the constructor of a
63 * FileBackendStore class, but with these additional settings:
64 * - class : The name of the backend class
65 * - isMultiMaster : This must be set for one backend.
66 * - template: : If given a backend name, this will use
67 * the config of that backend as a template.
68 * Values specified here take precedence.
69 * - syncChecks : Integer bitfield of internal backend sync checks to perform.
70 * Possible bits include the FileBackendMultiWrite::CHECK_* constants.
71 * There are constants for SIZE, TIME, and SHA1.
72 * The checks are done before allowing any file operations.
73 * - noPushQuickOps : (hack) Only apply doQuickOperations() to the master backend.
74 * - noPushDirConts : (hack) Only apply directory functions to the master backend.
76 * @param $config Array
79 public function __construct( array $config ) {
80 parent
::__construct( $config );
81 $this->syncChecks
= isset( $config['syncChecks'] )
82 ?
$config['syncChecks']
84 $this->noPushQuickOps
= isset( $config['noPushQuickOps'] )
85 ?
$config['noPushQuickOps']
87 $this->noPushDirConts
= isset( $config['noPushDirConts'] )
88 ?
$config['noPushDirConts']
90 // Construct backends here rather than via registration
91 // to keep these backends hidden from outside the proxy.
93 foreach ( $config['backends'] as $index => $config ) {
94 if ( isset( $config['template'] ) ) {
95 // Config is just a modified version of a registered backend's.
96 // This should only be used when that config is used only by this backend.
97 $config = $config + FileBackendGroup
::singleton()->config( $config['template'] );
99 $name = $config['name'];
100 if ( isset( $namesUsed[$name] ) ) { // don't break FileOp predicates
101 throw new MWException( "Two or more backends defined with the name $name." );
103 $namesUsed[$name] = 1;
104 // Alter certain sub-backend settings for sanity
105 unset( $config['readOnly'] ); // use proxy backend setting
106 unset( $config['fileJournal'] ); // use proxy backend journal
107 $config['wikiId'] = $this->wikiId
; // use the proxy backend wiki ID
108 $config['lockManager'] = 'nullLockManager'; // lock under proxy backend
109 if ( !empty( $config['isMultiMaster'] ) ) {
110 if ( $this->masterIndex
>= 0 ) {
111 throw new MWException( 'More than one master backend defined.' );
113 $this->masterIndex
= $index; // this is the "master"
114 $config['fileJournal'] = $this->fileJournal
; // log under proxy backend
116 // Create sub-backend object
117 if ( !isset( $config['class'] ) ) {
118 throw new MWException( 'No class given for a backend config.' );
120 $class = $config['class'];
121 $this->backends
[$index] = new $class( $config );
123 if ( $this->masterIndex
< 0 ) { // need backends and must have a master
124 throw new MWException( 'No master backend defined.' );
129 * @see FileBackend::doOperationsInternal()
132 final protected function doOperationsInternal( array $ops, array $opts ) {
133 $status = Status
::newGood();
135 $mbe = $this->backends
[$this->masterIndex
]; // convenience
137 // Get the paths to lock from the master backend
138 $realOps = $this->substOpBatchPaths( $ops, $mbe );
139 $paths = $mbe->getPathsToLockForOpsInternal( $mbe->getOperationsInternal( $realOps ) );
140 // Get the paths under the proxy backend's name
141 $paths['sh'] = $this->unsubstPaths( $paths['sh'] );
142 $paths['ex'] = $this->unsubstPaths( $paths['ex'] );
143 // Try to lock those files for the scope of this function...
144 if ( empty( $opts['nonLocking'] ) ) {
145 // Try to lock those files for the scope of this function...
146 $scopeLockS = $this->getScopedFileLocks( $paths['sh'], LockManager
::LOCK_UW
, $status );
147 $scopeLockE = $this->getScopedFileLocks( $paths['ex'], LockManager
::LOCK_EX
, $status );
148 if ( !$status->isOK() ) {
149 return $status; // abort
152 // Clear any cache entries (after locks acquired)
154 // Do a consistency check to see if the backends agree
155 $status->merge( $this->consistencyCheck( $this->fileStoragePathsForOps( $ops ) ) );
156 if ( !$status->isOK() ) {
157 return $status; // abort
159 // Actually attempt the operation batch on the master backend...
160 $masterStatus = $mbe->doOperations( $realOps, $opts );
161 $status->merge( $masterStatus );
162 // Propagate the operations to the clone backends...
163 foreach ( $this->backends
as $index => $backend ) {
164 if ( $index !== $this->masterIndex
) { // not done already
165 $realOps = $this->substOpBatchPaths( $ops, $backend );
166 $status->merge( $backend->doOperations( $realOps, $opts ) );
169 // Make 'success', 'successCount', and 'failCount' fields reflect
170 // the overall operation, rather than all the batches for each backend.
171 // Do this by only using success values from the master backend's batch.
172 $status->success
= $masterStatus->success
;
173 $status->successCount
= $masterStatus->successCount
;
174 $status->failCount
= $masterStatus->failCount
;
180 * Check that a set of files are consistent across all internal backends
182 * @param $paths Array List of storage paths
185 public function consistencyCheck( array $paths ) {
186 $status = Status
::newGood();
187 if ( $this->syncChecks
== 0 ||
count( $this->backends
) <= 1 ) {
188 return $status; // skip checks
191 $mBackend = $this->backends
[$this->masterIndex
];
192 foreach ( array_unique( $paths ) as $path ) {
193 $params = array( 'src' => $path, 'latest' => true );
194 $mParams = $this->substOpPaths( $params, $mBackend );
195 // Stat the file on the 'master' backend
196 $mStat = $mBackend->getFileStat( $mParams );
197 if ( $this->syncChecks
& self
::CHECK_SHA1
) {
198 $mSha1 = $mBackend->getFileSha1Base36( $mParams );
202 $mUsable = $mBackend->isPathUsableInternal( $mParams['src'] );
203 // Check of all clone backends agree with the master...
204 foreach ( $this->backends
as $index => $cBackend ) {
205 if ( $index === $this->masterIndex
) {
208 $cParams = $this->substOpPaths( $params, $cBackend );
209 $cStat = $cBackend->getFileStat( $cParams );
210 if ( $mStat ) { // file is in master
211 if ( !$cStat ) { // file should exist
212 $status->fatal( 'backend-fail-synced', $path );
215 if ( $this->syncChecks
& self
::CHECK_SIZE
) {
216 if ( $cStat['size'] != $mStat['size'] ) { // wrong size
217 $status->fatal( 'backend-fail-synced', $path );
221 if ( $this->syncChecks
& self
::CHECK_TIME
) {
222 $mTs = wfTimestamp( TS_UNIX
, $mStat['mtime'] );
223 $cTs = wfTimestamp( TS_UNIX
, $cStat['mtime'] );
224 if ( abs( $mTs - $cTs ) > 30 ) { // outdated file somewhere
225 $status->fatal( 'backend-fail-synced', $path );
229 if ( $this->syncChecks
& self
::CHECK_SHA1
) {
230 if ( $cBackend->getFileSha1Base36( $cParams ) !== $mSha1 ) { // wrong SHA1
231 $status->fatal( 'backend-fail-synced', $path );
235 } else { // file is not in master
236 if ( $cStat ) { // file should not exist
237 $status->fatal( 'backend-fail-synced', $path );
240 if ( $mUsable !== $cBackend->isPathUsableInternal( $cParams['src'] ) ) {
241 $status->fatal( 'backend-fail-synced', $path );
250 * Check that a set of files are consistent across all internal backends
251 * and re-synchronize those files againt the "multi master" if needed.
253 * @param $paths Array List of storage paths
256 public function resyncFiles( array $paths ) {
257 $status = Status
::newGood();
259 $mBackend = $this->backends
[$this->masterIndex
];
260 foreach ( $paths as $path ) {
261 $mPath = $this->substPaths( $path, $mBackend );
262 $mSha1 = $mBackend->getFileSha1Base36( array( 'src' => $mPath ) );
263 $mExist = $mBackend->fileExists( array( 'src' => $mPath ) );
264 // Check of all clone backends agree with the master...
265 foreach ( $this->backends
as $index => $cBackend ) {
266 if ( $index === $this->masterIndex
) {
269 $cPath = $this->substPaths( $path, $cBackend );
270 $cSha1 = $cBackend->getFileSha1Base36( array( 'src' => $cPath ) );
271 if ( $mSha1 === $cSha1 ) {
272 // already synced; nothing to do
273 } elseif ( $mSha1 ) { // file is in master
274 $fsFile = $mBackend->getLocalReference( array( 'src' => $mPath ) );
275 $status->merge( $cBackend->quickStore(
276 array( 'src' => $fsFile->getPath(), 'dst' => $cPath )
278 } elseif ( $mExist === false ) { // file is not in master
279 $status->merge( $cBackend->quickDelete( array( 'src' => $cPath ) ) );
288 * Get a list of file storage paths to read or write for a list of operations
290 * @param $ops Array Same format as doOperations()
291 * @return Array List of storage paths to files (does not include directories)
293 protected function fileStoragePathsForOps( array $ops ) {
295 foreach ( $ops as $op ) {
296 if ( isset( $op['src'] ) ) {
297 $paths[] = $op['src'];
299 if ( isset( $op['srcs'] ) ) {
300 $paths = array_merge( $paths, $op['srcs'] );
302 if ( isset( $op['dst'] ) ) {
303 $paths[] = $op['dst'];
306 return array_unique( $paths );
310 * Substitute the backend name in storage path parameters
311 * for a set of operations with that of a given internal backend.
313 * @param $ops Array List of file operation arrays
314 * @param $backend FileBackendStore
317 protected function substOpBatchPaths( array $ops, FileBackendStore
$backend ) {
318 $newOps = array(); // operations
319 foreach ( $ops as $op ) {
320 $newOp = $op; // operation
321 foreach ( array( 'src', 'srcs', 'dst', 'dir' ) as $par ) {
322 if ( isset( $newOp[$par] ) ) { // string or array
323 $newOp[$par] = $this->substPaths( $newOp[$par], $backend );
332 * Same as substOpBatchPaths() but for a single operation
334 * @param $ops array File operation array
335 * @param $backend FileBackendStore
338 protected function substOpPaths( array $ops, FileBackendStore
$backend ) {
339 $newOps = $this->substOpBatchPaths( array( $ops ), $backend );
344 * Substitute the backend of storage paths with an internal backend's name
346 * @param $paths Array|string List of paths or single string path
347 * @param $backend FileBackendStore
348 * @return Array|string
350 protected function substPaths( $paths, FileBackendStore
$backend ) {
352 '!^mwstore://' . preg_quote( $this->name
) . '/!',
353 StringUtils
::escapeRegexReplacement( "mwstore://{$backend->getName()}/" ),
354 $paths // string or array
359 * Substitute the backend of internal storage paths with the proxy backend's name
361 * @param $paths Array|string List of paths or single string path
362 * @return Array|string
364 protected function unsubstPaths( $paths ) {
366 '!^mwstore://([^/]+)!',
367 StringUtils
::escapeRegexReplacement( "mwstore://{$this->name}" ),
368 $paths // string or array
373 * @see FileBackend::doQuickOperationsInternal()
376 protected function doQuickOperationsInternal( array $ops ) {
377 $status = Status
::newGood();
378 // Do the operations on the master backend; setting Status fields...
379 $realOps = $this->substOpBatchPaths( $ops, $this->backends
[$this->masterIndex
] );
380 $masterStatus = $this->backends
[$this->masterIndex
]->doQuickOperations( $realOps );
381 $status->merge( $masterStatus );
382 // Propagate the operations to the clone backends...
383 if ( !$this->noPushQuickOps
) {
384 foreach ( $this->backends
as $index => $backend ) {
385 if ( $index !== $this->masterIndex
) { // not done already
386 $realOps = $this->substOpBatchPaths( $ops, $backend );
387 $status->merge( $backend->doQuickOperations( $realOps ) );
391 // Make 'success', 'successCount', and 'failCount' fields reflect
392 // the overall operation, rather than all the batches for each backend.
393 // Do this by only using success values from the master backend's batch.
394 $status->success
= $masterStatus->success
;
395 $status->successCount
= $masterStatus->successCount
;
396 $status->failCount
= $masterStatus->failCount
;
401 * @param $path string Storage path
402 * @return bool Path container should have dir changes pushed to all backends
404 protected function replicateContainerDirChanges( $path ) {
405 list( $b, $shortCont, $r ) = self
::splitStoragePath( $path );
406 return !in_array( $shortCont, $this->noPushDirConts
);
410 * @see FileBackend::doPrepare()
413 protected function doPrepare( array $params ) {
414 $status = Status
::newGood();
415 $replicate = $this->replicateContainerDirChanges( $params['dir'] );
416 foreach ( $this->backends
as $index => $backend ) {
417 if ( $replicate ||
$index == $this->masterIndex
) {
418 $realParams = $this->substOpPaths( $params, $backend );
419 $status->merge( $backend->doPrepare( $realParams ) );
426 * @see FileBackend::doSecure()
427 * @param $params array
430 protected function doSecure( array $params ) {
431 $status = Status
::newGood();
432 $replicate = $this->replicateContainerDirChanges( $params['dir'] );
433 foreach ( $this->backends
as $index => $backend ) {
434 if ( $replicate ||
$index == $this->masterIndex
) {
435 $realParams = $this->substOpPaths( $params, $backend );
436 $status->merge( $backend->doSecure( $realParams ) );
443 * @see FileBackend::doPublish()
444 * @param $params array
447 protected function doPublish( array $params ) {
448 $status = Status
::newGood();
449 $replicate = $this->replicateContainerDirChanges( $params['dir'] );
450 foreach ( $this->backends
as $index => $backend ) {
451 if ( $replicate ||
$index == $this->masterIndex
) {
452 $realParams = $this->substOpPaths( $params, $backend );
453 $status->merge( $backend->doPublish( $realParams ) );
460 * @see FileBackend::doClean()
461 * @param $params array
464 protected function doClean( array $params ) {
465 $status = Status
::newGood();
466 $replicate = $this->replicateContainerDirChanges( $params['dir'] );
467 foreach ( $this->backends
as $index => $backend ) {
468 if ( $replicate ||
$index == $this->masterIndex
) {
469 $realParams = $this->substOpPaths( $params, $backend );
470 $status->merge( $backend->doClean( $realParams ) );
477 * @see FileBackend::concatenate()
478 * @param $params array
481 public function concatenate( array $params ) {
482 // We are writing to an FS file, so we don't need to do this per-backend
483 $realParams = $this->substOpPaths( $params, $this->backends
[$this->masterIndex
] );
484 return $this->backends
[$this->masterIndex
]->concatenate( $realParams );
488 * @see FileBackend::fileExists()
489 * @param $params array
491 public function fileExists( array $params ) {
492 $realParams = $this->substOpPaths( $params, $this->backends
[$this->masterIndex
] );
493 return $this->backends
[$this->masterIndex
]->fileExists( $realParams );
497 * @see FileBackend::getFileTimestamp()
498 * @param $params array
499 * @return bool|string
501 public function getFileTimestamp( array $params ) {
502 $realParams = $this->substOpPaths( $params, $this->backends
[$this->masterIndex
] );
503 return $this->backends
[$this->masterIndex
]->getFileTimestamp( $realParams );
507 * @see FileBackend::getFileSize()
508 * @param $params array
511 public function getFileSize( array $params ) {
512 $realParams = $this->substOpPaths( $params, $this->backends
[$this->masterIndex
] );
513 return $this->backends
[$this->masterIndex
]->getFileSize( $realParams );
517 * @see FileBackend::getFileStat()
518 * @param $params array
519 * @return Array|bool|null
521 public function getFileStat( array $params ) {
522 $realParams = $this->substOpPaths( $params, $this->backends
[$this->masterIndex
] );
523 return $this->backends
[$this->masterIndex
]->getFileStat( $realParams );
527 * @see FileBackend::getFileContents()
528 * @param $params array
529 * @return bool|string
531 public function getFileContents( array $params ) {
532 $realParams = $this->substOpPaths( $params, $this->backends
[$this->masterIndex
] );
533 return $this->backends
[$this->masterIndex
]->getFileContents( $realParams );
537 * @see FileBackend::getFileSha1Base36()
538 * @param $params array
539 * @return bool|string
541 public function getFileSha1Base36( array $params ) {
542 $realParams = $this->substOpPaths( $params, $this->backends
[$this->masterIndex
] );
543 return $this->backends
[$this->masterIndex
]->getFileSha1Base36( $realParams );
547 * @see FileBackend::getFileProps()
548 * @param $params array
551 public function getFileProps( array $params ) {
552 $realParams = $this->substOpPaths( $params, $this->backends
[$this->masterIndex
] );
553 return $this->backends
[$this->masterIndex
]->getFileProps( $realParams );
557 * @see FileBackend::streamFile()
558 * @param $params array
561 public function streamFile( array $params ) {
562 $realParams = $this->substOpPaths( $params, $this->backends
[$this->masterIndex
] );
563 return $this->backends
[$this->masterIndex
]->streamFile( $realParams );
567 * @see FileBackend::getLocalReference()
568 * @param $params array
569 * @return FSFile|null
571 public function getLocalReference( array $params ) {
572 $realParams = $this->substOpPaths( $params, $this->backends
[$this->masterIndex
] );
573 return $this->backends
[$this->masterIndex
]->getLocalReference( $realParams );
577 * @see FileBackend::getLocalCopy()
578 * @param $params array
579 * @return null|TempFSFile
581 public function getLocalCopy( array $params ) {
582 $realParams = $this->substOpPaths( $params, $this->backends
[$this->masterIndex
] );
583 return $this->backends
[$this->masterIndex
]->getLocalCopy( $realParams );
587 * @see FileBackend::directoryExists()
588 * @param $params array
591 public function directoryExists( array $params ) {
592 $realParams = $this->substOpPaths( $params, $this->backends
[$this->masterIndex
] );
593 return $this->backends
[$this->masterIndex
]->directoryExists( $realParams );
597 * @see FileBackend::getSubdirectoryList()
598 * @param $params array
599 * @return Array|null|Traversable
601 public function getDirectoryList( array $params ) {
602 $realParams = $this->substOpPaths( $params, $this->backends
[$this->masterIndex
] );
603 return $this->backends
[$this->masterIndex
]->getDirectoryList( $realParams );
607 * @see FileBackend::getFileList()
608 * @param $params array
609 * @return Array|null|\Traversable
611 public function getFileList( array $params ) {
612 $realParams = $this->substOpPaths( $params, $this->backends
[$this->masterIndex
] );
613 return $this->backends
[$this->masterIndex
]->getFileList( $realParams );
617 * @see FileBackend::clearCache()
619 public function clearCache( array $paths = null ) {
620 foreach ( $this->backends
as $backend ) {
621 $realPaths = is_array( $paths ) ?
$this->substPaths( $paths, $backend ) : null;
622 $backend->clearCache( $realPaths );
627 * @see FileBackend::getScopedLocksForOps()
629 public function getScopedLocksForOps( array $ops, Status
$status ) {
630 $fileOps = $this->backends
[$this->masterIndex
]->getOperationsInternal( $ops );
631 // Get the paths to lock from the master backend
632 $paths = $this->backends
[$this->masterIndex
]->getPathsToLockForOpsInternal( $fileOps );
633 // Get the paths under the proxy backend's name
634 $paths['sh'] = $this->unsubstPaths( $paths['sh'] );
635 $paths['ex'] = $this->unsubstPaths( $paths['ex'] );
637 $this->getScopedFileLocks( $paths['sh'], LockManager
::LOCK_UW
, $status ),
638 $this->getScopedFileLocks( $paths['ex'], LockManager
::LOCK_EX
, $status )