3 * Proxy backend that mirrors writes to several internal backends.
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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.
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17 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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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 );
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'] );
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." );
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.' );
98 $this->masterIndex
= $index; // this is the "master"
99 $config['fileJournal'] = $this->fileJournal
; // log under proxy backend
101 // Create sub-backend object
102 if ( !isset( $config['class'] ) ) {
103 throw new MWException( 'No class given for a backend config.' );
105 $class = $config['class'];
106 $this->backends
[$index] = new $class( $config );
108 if ( $this->masterIndex
< 0 ) { // need backends and must have a master
109 throw new MWException( 'No master backend defined.' );
111 $this->syncChecks
= isset( $config['syncChecks'] )
112 ?
$config['syncChecks']
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( array_merge( $paths['sh'], $paths['ex'] ) ) );
144 if ( !$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
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->getFileSha1( $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->getFileSha1( $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 * Substitute the backend name in storage path parameters
239 * for a set of operations with that of a given internal backend.
241 * @param $ops Array List of file operation arrays
242 * @param $backend FileBackendStore
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 );
260 * Same as substOpBatchPaths() but for a single operation
262 * @param $ops array File operation array
263 * @param $backend FileBackendStore
266 protected function substOpPaths( array $ops, FileBackendStore
$backend ) {
267 $newOps = $this->substOpBatchPaths( array( $ops ), $backend );
272 * Substitute the backend of storage paths with an internal backend's name
274 * @param $paths Array|string List of paths or single string path
275 * @param $backend FileBackendStore
276 * @return Array|string
278 protected function substPaths( $paths, FileBackendStore
$backend ) {
280 '!^mwstore://' . preg_quote( $this->name
) . '/!',
281 StringUtils
::escapeRegexReplacement( "mwstore://{$backend->getName()}/" ),
282 $paths // string or array
287 * Substitute the backend of internal storage paths with the proxy backend's name
289 * @param $paths Array|string List of paths or single string path
290 * @return Array|string
292 protected function unsubstPaths( $paths ) {
294 '!^mwstore://([^/]+)!',
295 StringUtils
::escapeRegexReplacement( "mwstore://{$this->name}" ),
296 $paths // string or array
301 * @see FileBackend::doQuickOperationsInternal()
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 ) );
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
;
327 * @see FileBackend::doPrepare()
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 ) );
340 * @see FileBackend::doSecure()
341 * @param $params array
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 ) );
354 * @see FileBackend::doPublish()
355 * @param $params array
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 ) );
368 * @see FileBackend::doClean()
369 * @param $params array
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 ) );
382 * @see FileBackend::concatenate()
383 * @param $params array
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 );
393 * @see FileBackend::fileExists()
394 * @param $params array
396 public function fileExists( array $params ) {
397 $realParams = $this->substOpPaths( $params, $this->backends
[$this->masterIndex
] );
398 return $this->backends
[$this->masterIndex
]->fileExists( $realParams );
402 * @see FileBackend::getFileTimestamp()
403 * @param $params array
404 * @return bool|string
406 public function getFileTimestamp( array $params ) {
407 $realParams = $this->substOpPaths( $params, $this->backends
[$this->masterIndex
] );
408 return $this->backends
[$this->masterIndex
]->getFileTimestamp( $realParams );
412 * @see FileBackend::getFileSize()
413 * @param $params array
416 public function getFileSize( array $params ) {
417 $realParams = $this->substOpPaths( $params, $this->backends
[$this->masterIndex
] );
418 return $this->backends
[$this->masterIndex
]->getFileSize( $realParams );
422 * @see FileBackend::getFileStat()
423 * @param $params array
424 * @return Array|bool|null
426 public function getFileStat( array $params ) {
427 $realParams = $this->substOpPaths( $params, $this->backends
[$this->masterIndex
] );
428 return $this->backends
[$this->masterIndex
]->getFileStat( $realParams );
432 * @see FileBackend::getFileContents()
433 * @param $params array
434 * @return bool|string
436 public function getFileContents( array $params ) {
437 $realParams = $this->substOpPaths( $params, $this->backends
[$this->masterIndex
] );
438 return $this->backends
[$this->masterIndex
]->getFileContents( $realParams );
442 * @see FileBackend::getFileSha1Base36()
443 * @param $params array
444 * @return bool|string
446 public function getFileSha1Base36( array $params ) {
447 $realParams = $this->substOpPaths( $params, $this->backends
[$this->masterIndex
] );
448 return $this->backends
[$this->masterIndex
]->getFileSha1Base36( $realParams );
452 * @see FileBackend::getFileProps()
453 * @param $params array
456 public function getFileProps( array $params ) {
457 $realParams = $this->substOpPaths( $params, $this->backends
[$this->masterIndex
] );
458 return $this->backends
[$this->masterIndex
]->getFileProps( $realParams );
462 * @see FileBackend::streamFile()
463 * @param $params array
466 public function streamFile( array $params ) {
467 $realParams = $this->substOpPaths( $params, $this->backends
[$this->masterIndex
] );
468 return $this->backends
[$this->masterIndex
]->streamFile( $realParams );
472 * @see FileBackend::getLocalReference()
473 * @param $params array
474 * @return FSFile|null
476 public function getLocalReference( array $params ) {
477 $realParams = $this->substOpPaths( $params, $this->backends
[$this->masterIndex
] );
478 return $this->backends
[$this->masterIndex
]->getLocalReference( $realParams );
482 * @see FileBackend::getLocalCopy()
483 * @param $params array
484 * @return null|TempFSFile
486 public function getLocalCopy( array $params ) {
487 $realParams = $this->substOpPaths( $params, $this->backends
[$this->masterIndex
] );
488 return $this->backends
[$this->masterIndex
]->getLocalCopy( $realParams );
492 * @see FileBackend::directoryExists()
493 * @param $params array
496 public function directoryExists( array $params ) {
497 $realParams = $this->substOpPaths( $params, $this->backends
[$this->masterIndex
] );
498 return $this->backends
[$this->masterIndex
]->directoryExists( $realParams );
502 * @see FileBackend::getSubdirectoryList()
503 * @param $params array
504 * @return Array|null|Traversable
506 public function getDirectoryList( array $params ) {
507 $realParams = $this->substOpPaths( $params, $this->backends
[$this->masterIndex
] );
508 return $this->backends
[$this->masterIndex
]->getDirectoryList( $realParams );
512 * @see FileBackend::getFileList()
513 * @param $params array
514 * @return Array|null|\Traversable
516 public function getFileList( array $params ) {
517 $realParams = $this->substOpPaths( $params, $this->backends
[$this->masterIndex
] );
518 return $this->backends
[$this->masterIndex
]->getFileList( $realParams );
522 * @see FileBackend::clearCache()
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 );
532 * @see FileBackend::getScopedLocksForOps()
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'] );
542 $this->getScopedFileLocks( $paths['sh'], LockManager
::LOCK_UW
, $status ),
543 $this->getScopedFileLocks( $paths['ex'], LockManager
::LOCK_EX
, $status )