f4a7eac00c96602abe651d05b944a41705201ba5
3 * Proxy backend that mirrors writes to several internal backends.
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.
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 /* Possible internal backend consistency checks */
54 * Construct a proxy backend that consists of several internal backends.
55 * Locking, journaling, and read-only checks are handled by the proxy backend.
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
73 public function __construct( array $config ) {
74 parent
::__construct( $config );
75 $this->syncChecks
= isset( $config['syncChecks'] )
76 ?
$config['syncChecks']
78 // Construct backends here rather than via registration
79 // to keep these backends hidden from outside the proxy.
81 foreach ( $config['backends'] as $index => $config ) {
82 if ( isset( $config['template'] ) ) {
83 // Config is just a modified version of a registered backend's.
84 // This should only be used when that config is used only by this backend.
85 $config = $config + FileBackendGroup
::singleton()->config( $config['template'] );
87 $name = $config['name'];
88 if ( isset( $namesUsed[$name] ) ) { // don't break FileOp predicates
89 throw new MWException( "Two or more backends defined with the name $name." );
91 $namesUsed[$name] = 1;
92 // Alter certain sub-backend settings for sanity
93 unset( $config['readOnly'] ); // use proxy backend setting
94 unset( $config['fileJournal'] ); // use proxy backend journal
95 $config['wikiId'] = $this->wikiId
; // use the proxy backend wiki ID
96 $config['lockManager'] = 'nullLockManager'; // lock under proxy backend
97 if ( !empty( $config['isMultiMaster'] ) ) {
98 if ( $this->masterIndex
>= 0 ) {
99 throw new MWException( 'More than one master backend defined.' );
101 $this->masterIndex
= $index; // this is the "master"
102 $config['fileJournal'] = $this->fileJournal
; // log under proxy backend
104 // Create sub-backend object
105 if ( !isset( $config['class'] ) ) {
106 throw new MWException( 'No class given for a backend config.' );
108 $class = $config['class'];
109 $this->backends
[$index] = new $class( $config );
111 if ( $this->masterIndex
< 0 ) { // need backends and must have a master
112 throw new MWException( 'No master backend defined.' );
117 * @see FileBackend::doOperationsInternal()
120 final protected function doOperationsInternal( array $ops, array $opts ) {
121 $status = Status
::newGood();
123 $mbe = $this->backends
[$this->masterIndex
]; // convenience
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
140 // Clear any cache entries (after locks acquired)
142 // Do a consistency check to see if the backends agree
143 $status->merge( $this->consistencyCheck( $this->fileStoragePathsForOps( $ops ) ) );
144 if ( !$status->isOK() ) {
145 return $status; // abort
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 ) );
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
;
168 * Check that a set of files are consistent across all internal backends
170 * @param $paths Array List of storage paths
173 public function consistencyCheck( array $paths ) {
174 $status = Status
::newGood();
175 if ( $this->syncChecks
== 0 ||
count( $this->backends
) <= 1 ) {
176 return $status; // skip checks
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->getFileSha1Base36( $mParams );
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
) {
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 );
203 if ( $this->syncChecks
& self
::CHECK_SIZE
) {
204 if ( $cStat['size'] != $mStat['size'] ) { // wrong size
205 $status->fatal( 'backend-fail-synced', $path );
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 );
217 if ( $this->syncChecks
& self
::CHECK_SHA1
) {
218 if ( $cBackend->getFileSha1Base36( $cParams ) !== $mSha1 ) { // wrong SHA1
219 $status->fatal( 'backend-fail-synced', $path );
223 } else { // file is not in master
224 if ( $cStat ) { // file should not exist
225 $status->fatal( 'backend-fail-synced', $path );
228 if ( $mUsable !== $cBackend->isPathUsableInternal( $cParams['src'] ) ) {
229 $status->fatal( 'backend-fail-synced', $path );
238 * Check that a set of files are consistent across all internal backends
239 * and re-synchronize those files againt the "multi master" if needed.
241 * @param $paths Array List of storage paths
244 public function resyncFiles( array $paths ) {
245 $status = Status
::newGood();
247 $mBackend = $this->backends
[$this->masterIndex
];
248 foreach ( $paths as $path ) {
249 $mPath = $this->substPaths( $path, $mBackend );
250 $mSha1 = $mBackend->getFileSha1Base36( array( 'src' => $mPath ) );
251 $mExist = $mBackend->fileExists( array( 'src' => $mPath ) );
252 // Check of all clone backends agree with the master...
253 foreach ( $this->backends
as $index => $cBackend ) {
254 if ( $index === $this->masterIndex
) {
257 $cPath = $this->substPaths( $path, $cBackend );
258 $cSha1 = $cBackend->getFileSha1Base36( array( 'src' => $cPath ) );
259 if ( $mSha1 === $cSha1 ) {
260 // already synced; nothing to do
261 } elseif ( $mSha1 ) { // file is in master
262 $fsFile = $mBackend->getLocalReference( array( 'src' => $mPath ) );
263 $status->merge( $cBackend->quickStore(
264 array( 'src' => $fsFile->getPath(), 'dst' => $cPath )
266 } elseif ( $mExist === false ) { // file is not in master
267 $status->merge( $cBackend->quickDelete( array( 'src' => $cPath ) ) );
276 * Get a list of file storage paths to read or write for a list of operations
278 * @param $ops Array Same format as doOperations()
279 * @return Array List of storage paths to files (does not include directories)
281 protected function fileStoragePathsForOps( array $ops ) {
283 foreach ( $ops as $op ) {
284 if ( isset( $op['src'] ) ) {
285 $paths[] = $op['src'];
287 if ( isset( $op['srcs'] ) ) {
288 $paths = array_merge( $paths, $op['srcs'] );
290 if ( isset( $op['dst'] ) ) {
291 $paths[] = $op['dst'];
294 return array_unique( $paths );
298 * Substitute the backend name in storage path parameters
299 * for a set of operations with that of a given internal backend.
301 * @param $ops Array List of file operation arrays
302 * @param $backend FileBackendStore
305 protected function substOpBatchPaths( array $ops, FileBackendStore
$backend ) {
306 $newOps = array(); // operations
307 foreach ( $ops as $op ) {
308 $newOp = $op; // operation
309 foreach ( array( 'src', 'srcs', 'dst', 'dir' ) as $par ) {
310 if ( isset( $newOp[$par] ) ) { // string or array
311 $newOp[$par] = $this->substPaths( $newOp[$par], $backend );
320 * Same as substOpBatchPaths() but for a single operation
322 * @param $ops array File operation array
323 * @param $backend FileBackendStore
326 protected function substOpPaths( array $ops, FileBackendStore
$backend ) {
327 $newOps = $this->substOpBatchPaths( array( $ops ), $backend );
332 * Substitute the backend of storage paths with an internal backend's name
334 * @param $paths Array|string List of paths or single string path
335 * @param $backend FileBackendStore
336 * @return Array|string
338 protected function substPaths( $paths, FileBackendStore
$backend ) {
340 '!^mwstore://' . preg_quote( $this->name
) . '/!',
341 StringUtils
::escapeRegexReplacement( "mwstore://{$backend->getName()}/" ),
342 $paths // string or array
347 * Substitute the backend of internal storage paths with the proxy backend's name
349 * @param $paths Array|string List of paths or single string path
350 * @return Array|string
352 protected function unsubstPaths( $paths ) {
354 '!^mwstore://([^/]+)!',
355 StringUtils
::escapeRegexReplacement( "mwstore://{$this->name}" ),
356 $paths // string or array
361 * @see FileBackend::doQuickOperationsInternal()
364 protected function doQuickOperationsInternal( array $ops ) {
365 $status = Status
::newGood();
366 // Do the operations on the master backend; setting Status fields...
367 $realOps = $this->substOpBatchPaths( $ops, $this->backends
[$this->masterIndex
] );
368 $masterStatus = $this->backends
[$this->masterIndex
]->doQuickOperations( $realOps );
369 $status->merge( $masterStatus );
370 // Propagate the operations to the clone backends...
371 foreach ( $this->backends
as $index => $backend ) {
372 if ( $index !== $this->masterIndex
) { // not done already
373 $realOps = $this->substOpBatchPaths( $ops, $backend );
374 $status->merge( $backend->doQuickOperations( $realOps ) );
377 // Make 'success', 'successCount', and 'failCount' fields reflect
378 // the overall operation, rather than all the batches for each backend.
379 // Do this by only using success values from the master backend's batch.
380 $status->success
= $masterStatus->success
;
381 $status->successCount
= $masterStatus->successCount
;
382 $status->failCount
= $masterStatus->failCount
;
387 * @see FileBackend::doPrepare()
390 protected function doPrepare( array $params ) {
391 $status = Status
::newGood();
392 foreach ( $this->backends
as $backend ) {
393 $realParams = $this->substOpPaths( $params, $backend );
394 $status->merge( $backend->doPrepare( $realParams ) );
400 * @see FileBackend::doSecure()
401 * @param $params array
404 protected function doSecure( array $params ) {
405 $status = Status
::newGood();
406 foreach ( $this->backends
as $backend ) {
407 $realParams = $this->substOpPaths( $params, $backend );
408 $status->merge( $backend->doSecure( $realParams ) );
414 * @see FileBackend::doPublish()
415 * @param $params array
418 protected function doPublish( array $params ) {
419 $status = Status
::newGood();
420 foreach ( $this->backends
as $backend ) {
421 $realParams = $this->substOpPaths( $params, $backend );
422 $status->merge( $backend->doPublish( $realParams ) );
428 * @see FileBackend::doClean()
429 * @param $params array
432 protected function doClean( array $params ) {
433 $status = Status
::newGood();
434 foreach ( $this->backends
as $backend ) {
435 $realParams = $this->substOpPaths( $params, $backend );
436 $status->merge( $backend->doClean( $realParams ) );
442 * @see FileBackend::concatenate()
443 * @param $params array
446 public function concatenate( array $params ) {
447 // We are writing to an FS file, so we don't need to do this per-backend
448 $realParams = $this->substOpPaths( $params, $this->backends
[$this->masterIndex
] );
449 return $this->backends
[$this->masterIndex
]->concatenate( $realParams );
453 * @see FileBackend::fileExists()
454 * @param $params array
456 public function fileExists( array $params ) {
457 $realParams = $this->substOpPaths( $params, $this->backends
[$this->masterIndex
] );
458 return $this->backends
[$this->masterIndex
]->fileExists( $realParams );
462 * @see FileBackend::getFileTimestamp()
463 * @param $params array
464 * @return bool|string
466 public function getFileTimestamp( array $params ) {
467 $realParams = $this->substOpPaths( $params, $this->backends
[$this->masterIndex
] );
468 return $this->backends
[$this->masterIndex
]->getFileTimestamp( $realParams );
472 * @see FileBackend::getFileSize()
473 * @param $params array
476 public function getFileSize( array $params ) {
477 $realParams = $this->substOpPaths( $params, $this->backends
[$this->masterIndex
] );
478 return $this->backends
[$this->masterIndex
]->getFileSize( $realParams );
482 * @see FileBackend::getFileStat()
483 * @param $params array
484 * @return Array|bool|null
486 public function getFileStat( array $params ) {
487 $realParams = $this->substOpPaths( $params, $this->backends
[$this->masterIndex
] );
488 return $this->backends
[$this->masterIndex
]->getFileStat( $realParams );
492 * @see FileBackend::getFileContents()
493 * @param $params array
494 * @return bool|string
496 public function getFileContents( array $params ) {
497 $realParams = $this->substOpPaths( $params, $this->backends
[$this->masterIndex
] );
498 return $this->backends
[$this->masterIndex
]->getFileContents( $realParams );
502 * @see FileBackend::getFileSha1Base36()
503 * @param $params array
504 * @return bool|string
506 public function getFileSha1Base36( array $params ) {
507 $realParams = $this->substOpPaths( $params, $this->backends
[$this->masterIndex
] );
508 return $this->backends
[$this->masterIndex
]->getFileSha1Base36( $realParams );
512 * @see FileBackend::getFileProps()
513 * @param $params array
516 public function getFileProps( array $params ) {
517 $realParams = $this->substOpPaths( $params, $this->backends
[$this->masterIndex
] );
518 return $this->backends
[$this->masterIndex
]->getFileProps( $realParams );
522 * @see FileBackend::streamFile()
523 * @param $params array
526 public function streamFile( array $params ) {
527 $realParams = $this->substOpPaths( $params, $this->backends
[$this->masterIndex
] );
528 return $this->backends
[$this->masterIndex
]->streamFile( $realParams );
532 * @see FileBackend::getLocalReference()
533 * @param $params array
534 * @return FSFile|null
536 public function getLocalReference( array $params ) {
537 $realParams = $this->substOpPaths( $params, $this->backends
[$this->masterIndex
] );
538 return $this->backends
[$this->masterIndex
]->getLocalReference( $realParams );
542 * @see FileBackend::getLocalCopy()
543 * @param $params array
544 * @return null|TempFSFile
546 public function getLocalCopy( array $params ) {
547 $realParams = $this->substOpPaths( $params, $this->backends
[$this->masterIndex
] );
548 return $this->backends
[$this->masterIndex
]->getLocalCopy( $realParams );
552 * @see FileBackend::directoryExists()
553 * @param $params array
556 public function directoryExists( array $params ) {
557 $realParams = $this->substOpPaths( $params, $this->backends
[$this->masterIndex
] );
558 return $this->backends
[$this->masterIndex
]->directoryExists( $realParams );
562 * @see FileBackend::getSubdirectoryList()
563 * @param $params array
564 * @return Array|null|Traversable
566 public function getDirectoryList( array $params ) {
567 $realParams = $this->substOpPaths( $params, $this->backends
[$this->masterIndex
] );
568 return $this->backends
[$this->masterIndex
]->getDirectoryList( $realParams );
572 * @see FileBackend::getFileList()
573 * @param $params array
574 * @return Array|null|\Traversable
576 public function getFileList( array $params ) {
577 $realParams = $this->substOpPaths( $params, $this->backends
[$this->masterIndex
] );
578 return $this->backends
[$this->masterIndex
]->getFileList( $realParams );
582 * @see FileBackend::clearCache()
584 public function clearCache( array $paths = null ) {
585 foreach ( $this->backends
as $backend ) {
586 $realPaths = is_array( $paths ) ?
$this->substPaths( $paths, $backend ) : null;
587 $backend->clearCache( $realPaths );
592 * @see FileBackend::getScopedLocksForOps()
594 public function getScopedLocksForOps( array $ops, Status
$status ) {
595 $fileOps = $this->backends
[$this->masterIndex
]->getOperationsInternal( $ops );
596 // Get the paths to lock from the master backend
597 $paths = $this->backends
[$this->masterIndex
]->getPathsToLockForOpsInternal( $fileOps );
598 // Get the paths under the proxy backend's name
599 $paths['sh'] = $this->unsubstPaths( $paths['sh'] );
600 $paths['ex'] = $this->unsubstPaths( $paths['ex'] );
602 $this->getScopedFileLocks( $paths['sh'], LockManager
::LOCK_UW
, $status ),
603 $this->getScopedFileLocks( $paths['ex'], LockManager
::LOCK_EX
, $status )