includes/externalstore/ExternalStoreMwstore.php

   1 <?php
   2 /**
   3  * This program is free software; you can redistribute it and/or modify
   4  * it under the terms of the GNU General Public License as published by
   5  * the Free Software Foundation; either version 2 of the License, or
   6  * (at your option) any later version.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along
  14  * with this program; if not, write to the Free Software Foundation, Inc.,
  15  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  16  * http://www.gnu.org/copyleft/gpl.html
  17  *
  18  * @file
  19  */
  20
  21 use MediaWiki\FileBackend\FileBackendGroup;
  22 use MediaWiki\MediaWikiServices;
  23 use MediaWiki\WikiMap\WikiMap;
  24 use Wikimedia\FileBackend\FileBackend;
  25 use Wikimedia\FileBackend\FSFileBackend;
  26
  27 /**
  28  * External storage in a FileBackend.
  29  *
  30  * In this system, each store "location" maps to the name of a file backend.
  31  * The file backends must be defined in $wgFileBackends and must be global
  32  * and fully qualified with a global "wikiId" prefix in the configuration.
  33  *
  34  * @see ExternalStoreAccess
  35  * @ingroup ExternalStorage
  36  * @since 1.21
  37  */
  38 class ExternalStoreMwstore extends ExternalStoreMedium {
  39         /** @var FileBackendGroup */
  40         private $fbGroup;
  41
  42         /**
  43          * @see ExternalStoreMedium::__construct()
  44          * @param array $params Additional parameters include:
  45          *   - fbGroup: a FileBackendGroup instance
  46          */
  47         public function __construct( array $params ) {
  48                 parent::__construct( $params );
  49                 if ( !isset( $params['fbGroup'] ) || !( $params['fbGroup'] instanceof FileBackendGroup ) ) {
  50                         throw new InvalidArgumentException( "FileBackendGroup required in 'fbGroup' field." );
  51                 }
  52                 $this->fbGroup = $params['fbGroup'];
  53         }
  54
  55         /**
  56          * Fetch data from a given external store URL
  57          *
  58          * @see ExternalStoreMedium::fetchFromURL()
  59          * @param string $url An external store URL in the form of mwstore://backend/container/wiki/id
  60          * @return string|bool
  61          */
  62         public function fetchFromURL( $url ) {
  63                 $be = $this->fbGroup->backendFromPath( $url );
  64                 if ( $be instanceof FileBackend ) {
  65                         // We don't need "latest" since objects are immutable and
  66                         // backends should at least have "read-after-create" consistency.
  67                         return $be->getFileContents( [ 'src' => $url ] );
  68                 }
  69
  70                 return false;
  71         }
  72
  73         /**
  74          * Fetch data from given external store URLs.
  75          * The URLs are in the form of mwstore://backend/container/wiki/id
  76          *
  77          * @param array $urls An array of external store URLs
  78          * @return array A map from url to stored content. Failed results are not represented.
  79          */
  80         public function batchFetchFromURLs( array $urls ) {
  81                 $pathsByBackend = [];
  82                 foreach ( $urls as $url ) {
  83                         $be = $this->fbGroup->backendFromPath( $url );
  84                         if ( $be instanceof FileBackend ) {
  85                                 $pathsByBackend[$be->getName()][] = $url;
  86                         }
  87                 }
  88                 $blobs = [];
  89                 foreach ( $pathsByBackend as $backendName => $paths ) {
  90                         $be = $this->fbGroup->get( $backendName );
  91                         $blobs += $be->getFileContentsMulti( [ 'srcs' => $paths ] );
  92                 }
  93
  94                 return $blobs;
  95         }
  96
  97         public function store( $backend, $data ) {
  98                 $be = $this->fbGroup->get( $backend );
  99                 // Get three random base 36 characters to act as shard directories
 100                 $rand = Wikimedia\base_convert( (string)mt_rand( 0, 46655 ), 10, 36, 3 );
 101                 // Make sure ID is roughly lexicographically increasing for performance
 102                 $gen = MediaWikiServices::getInstance()->getGlobalIdGenerator();
 103                 $id = str_pad( $gen->newTimestampedUID128( 32 ), 26, '0', STR_PAD_LEFT );
 104                 // Segregate items by DB domain ID for the sake of bookkeeping
 105                 $domain = $this->isDbDomainExplicit
 106                         ? $this->dbDomain
 107                         // @FIXME: this does not include the schema for b/c but it ideally should
 108                         : WikiMap::getWikiIdFromDbDomain( $this->dbDomain );
 109                 $url = $be->getContainerStoragePath( 'data' ) . '/' . rawurlencode( $domain );
 110                 // Use directory/container sharding
 111                 $url .= ( $be instanceof FSFileBackend )
 112                         ? "/{$rand[0]}/{$rand[1]}/{$rand[2]}/{$id}" // keep directories small
 113                         : "/{$rand[0]}/{$rand[1]}/{$id}"; // container sharding is only 2-levels
 114
 115                 $be->prepare( [ 'dir' => dirname( $url ), 'noAccess' => 1, 'noListing' => 1 ] );
 116                 $status = $be->create( [ 'dst' => $url, 'content' => $data ] );
 117
 118                 if ( $status->isOK() ) {
 119                         return $url;
 120                 }
 121
 122                 throw new ExternalStoreException( __METHOD__ . ": operation failed: $status" );
 123         }
 124
 125         public function isReadOnly( $backend ) {
 126                 if ( parent::isReadOnly( $backend ) ) {
 127                         return true;
 128                 }
 129
 130                 $be = $this->fbGroup->get( $backend );
 131
 132                 return $be->isReadOnly();
 133         }
 134 }