summaryrefslogtreecommitdiff
path: root/maintenance/syncFileBackend.php
blob: a29647b50a29b0e78be0985d5a412bd2ff7fc496 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
<?php
/**
 * Sync one file backend to another based on the journal of later.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 * http://www.gnu.org/copyleft/gpl.html
 *
 * @file
 * @ingroup Maintenance
 */

require_once( __DIR__ . '/Maintenance.php' );

/**
 * Maintenance script that syncs one file backend to another based on
 * the journal of later.
 *
 * @ingroup Maintenance
 */
class SyncFileBackend extends Maintenance {
	public function __construct() {
		parent::__construct();
		$this->mDescription = "Sync one file backend with another using the journal";
		$this->addOption( 'src', 'Name of backend to sync from', true, true );
		$this->addOption( 'dst', 'Name of destination backend to sync', true, true );
		$this->addOption( 'start', 'Starting journal ID', false, true );
		$this->addOption( 'end', 'Ending journal ID', false, true );
		$this->addOption( 'posdir', 'Directory to read/record journal positions', false, true );
		$this->addOption( 'verbose', 'Verbose mode', false, false, 'v' );
		$this->setBatchSize( 50 );
	}

	public function execute() {
		$src = FileBackendGroup::singleton()->get( $this->getOption( 'src' ) );
		$dst = FileBackendGroup::singleton()->get( $this->getOption( 'dst' ) );

		$posDir = $this->getOption( 'posdir' );
		$posFile = $posDir ? $posDir . '/' . wfWikiID() : false;

		$start = $this->getOption( 'start', 0 );
		if ( !$start && $posFile && is_dir( $posDir ) ) {
			$start = is_file( $posFile )
				? (int)trim( file_get_contents( $posFile ) )
				: 0;
			++$start; // we already did this ID, start with the next one
			$startFromPosFile = true;
		} else {
			$startFromPosFile = false;
		}
		$end = $this->getOption( 'end', INF );

		$this->output( "Synchronizing backend '{$dst->getName()}' to '{$src->getName()}'...\n" );
		$this->output( "Starting journal position is $start.\n" );
		if ( is_finite( $end ) ) {
			$this->output( "Ending journal position is $end.\n" );
		}

		// Actually sync the dest backend with the reference backend
		$lastOKPos = $this->syncBackends( $src, $dst, $start, $end );

		// Update the sync position file
		if ( $startFromPosFile && $lastOKPos >= $start ) { // successfully advanced
			if ( file_put_contents( $posFile, $lastOKPos, LOCK_EX ) !== false ) {
				$this->output( "Updated journal position file.\n" );
			} else {
				$this->output( "Could not update journal position file.\n" );
			}
		}

		if ( $lastOKPos === false ) {
			if ( !$start ) {
				$this->output( "No journal entries found.\n" );
			} else {
				$this->output( "No new journal entries found.\n" );
			}
		} else {
			$this->output( "Stopped synchronization at journal position $lastOKPos.\n" );
		}

		if ( $this->isQuiet() ) {
			print $lastOKPos; // give a single machine-readable number
		}
	}

	/**
	 * Sync $dst backend to $src backend based on the $src logs given after $start.
	 * Returns the journal entry ID this advanced to and handled (inclusive).
	 *
	 * @param $src FileBackend
	 * @param $dst FileBackend
	 * @param $start integer Starting journal position
	 * @param $end integer Starting journal position
	 * @return integer|false Journal entry ID or false if there are none
	 */
	protected function syncBackends( FileBackend $src, FileBackend $dst, $start, $end ) {
		$lastOKPos = 0; // failed
		$first = true; // first batch

		if ( $start > $end ) { // sanity
			$this->error( "Error: given starting ID greater than ending ID.", 1 );
		}

		do {
			$limit = min( $this->mBatchSize, $end - $start + 1 ); // don't go pass ending ID
			$this->output( "Doing id $start to " . ( $start + $limit - 1 ) . "...\n" );

			$entries = $src->getJournal()->getChangeEntries( $start, $limit, $next );
			$start = $next; // start where we left off next time
			if ( $first && !count( $entries ) ) {
				return false; // nothing to do
			}
			$first = false;

			$lastPosInBatch = 0;
			$pathsInBatch = array(); // changed paths
			foreach ( $entries as $entry ) {
				if ( $entry['op'] !== 'null' ) { // null ops are just for reference
					$pathsInBatch[$entry['path']] = 1; // remove duplicates
				}
				$lastPosInBatch = $entry['id'];
			}

			$status = $this->syncFileBatch( array_keys( $pathsInBatch ), $src, $dst );
			if ( $status->isOK() ) {
				$lastOKPos = max( $lastOKPos, $lastPosInBatch );
			} else {
				$this->error( print_r( $status->getErrorsArray(), true ) );
				break; // no gaps; everything up to $lastPos must be OK
			}

			if ( !$start ) {
				$this->output( "End of journal entries.\n" );
			}
		} while ( $start && $start <= $end );

		return $lastOKPos;
	}

	/**
	 * Sync particular files of backend $src to the corresponding $dst backend files
	 *
	 * @param $paths Array
	 * @param $src FileBackend
	 * @param $dst FileBackend
	 * @return Status
	 */
	protected function syncFileBatch( array $paths, FileBackend $src, FileBackend $dst ) {
		$status = Status::newGood();
		if ( !count( $paths ) ) {
			return $status; // nothing to do
		}

		// Source: convert internal backend names (FileBackendMultiWrite) to the public one
		$sPaths = $this->replaceNamePaths( $paths, $src );
		// Destination: get corresponding path name
		$dPaths = $this->replaceNamePaths( $paths, $dst );

		// Lock the live backend paths from modification
		$sLock = $src->getScopedFileLocks( $sPaths, LockManager::LOCK_UW, $status );
		$eLock = $dst->getScopedFileLocks( $dPaths, LockManager::LOCK_EX, $status );
		if ( !$status->isOK() ) {
			return $status;
		}

		$ops = array();
		$fsFiles = array();
		foreach ( $sPaths as $i => $sPath ) {
			$dPath = $dPaths[$i]; // destination
			$sExists = $src->fileExists( array( 'src' => $sPath, 'latest' => 1 ) );
			if ( $sExists === true ) { // exists in source
				if ( $this->filesAreSame( $src, $dst, $sPath, $dPath ) ) {
					continue; // avoid local copies for non-FS backends
				}
				// Note: getLocalReference() is fast for FS backends
				$fsFile = $src->getLocalReference( array( 'src' => $sPath, 'latest' => 1 ) );
				if ( !$fsFile ) {
					$this->error( "Unable to sync '$dPath': could not get local copy." );
					$status->fatal( 'backend-fail-internal', $src->getName() );
					return $status;
				}
				$fsFiles[] = $fsFile; // keep TempFSFile objects alive as needed
				// Note: prepare() is usually fast for key/value backends
				$status->merge( $dst->prepare( array(
					'dir' => dirname( $dPath ), 'bypassReadOnly' => 1 ) ) );
				if ( !$status->isOK() ) {
					return $status;
				}
				$ops[] = array( 'op' => 'store',
					'src' => $fsFile->getPath(), 'dst' => $dPath, 'overwrite' => 1 );
			} elseif ( $sExists === false ) { // does not exist in source
				$ops[] = array( 'op' => 'delete', 'src' => $dPath, 'ignoreMissingSource' => 1 );
			} else { // error
				$this->error( "Unable to sync '$dPath': could not stat file." );
				$status->fatal( 'backend-fail-internal', $src->getName() );
				return $status;
			}
		}

		$t_start = microtime( true );
		$status = $dst->doQuickOperations( $ops, array( 'bypassReadOnly' => 1 ) );
		if ( !$status->isOK() ) {
			sleep( 10 ); // wait and retry copy again
			$status = $dst->doQuickOperations( $ops, array( 'bypassReadOnly' => 1 ) );
		}
		$ellapsed_ms = floor( ( microtime( true ) - $t_start ) * 1000 );
		if ( $status->isOK() && $this->getOption( 'verbose' ) ) {
			$this->output( "Synchronized these file(s) [{$ellapsed_ms}ms]:\n" .
				implode( "\n", $dPaths ) . "\n" );
		}

		return $status;
	}

	/**
	 * Substitute the backend name of storage paths with that of a given one
	 *
	 * @param $paths Array|string List of paths or single string path
	 * @return Array|string
	 */
	protected function replaceNamePaths( $paths, FileBackend $backend ) {
		return preg_replace(
			'!^mwstore://([^/]+)!',
			StringUtils::escapeRegexReplacement( "mwstore://" . $backend->getName() ),
			$paths // string or array
		);
	}

	protected function filesAreSame( FileBackend $src, FileBackend $dst, $sPath, $dPath ) {
		return (
			( $src->getFileSize( array( 'src' => $sPath ) )
				=== $dst->getFileSize( array( 'src' => $dPath ) ) // short-circuit
			) && ( $src->getFileSha1Base36( array( 'src' => $sPath ) )
				=== $dst->getFileSha1Base36( array( 'src' => $dPath ) )
			)
		);
	}
}

$maintClass = "SyncFileBackend";
require_once( RUN_MAINTENANCE_IF_MAIN );