Mount the old previews in a separate folder for the multi bucket setup and check in them before using the actual locations

Signed-off-by: Morris Jobke <hey@morrisjobke.de>

lib/private/Files/Mount/ObjectStorePreviewCacheMountProvider.php

@@ -26,6 +26,8 @@ declare(strict_types=1);
 namespace OC\Files\Mount;
 
 use OC\Files\ObjectStore\AppdataPreviewObjectStoreStorage;
+use OC\Files\ObjectStore\ObjectStoreStorage;
+use OC\Files\Storage\Wrapper\Jail;
 use OCP\Files\Config\IRootMountProvider;
 use OCP\Files\Storage\IStorageFactory;
 use OCP\IConfig;
@@ -45,6 +47,10 @@ class ObjectStorePreviewCacheMountProvider implements IRootMountProvider {
 		$this->config = $config;
 	}
 
+	/**
+	 * @return MountPoint[]
+	 * @throws \Exception
+	 */
 	public function getRootMounts(IStorageFactory $loader): array {
 		if (!is_array($this->config->getSystemValue('objectstore_multibucket'))) {
 			return [];
@@ -65,12 +71,25 @@ class ObjectStorePreviewCacheMountProvider implements IRootMountProvider {
 				$i++;
 			}
 		}
+
+		$rootStorageArguments = $this->getMultiBucketObjectStoreForRoot();
+		$fakeRootStorage = new ObjectStoreStorage($rootStorageArguments);
+		$fakeRootStorageJail = new Jail([
+			'storage' => $fakeRootStorage,
+			'root' => '/appdata_' . $instanceId . '/preview',
+		]);
+
+		// add a fallback location to be able to fetch existing previews from the old bucket
+		$mountPoints[] = new MountPoint(
+			$fakeRootStorageJail,
+			'/appdata_' . $instanceId . '/preview/old-multibucket',
+			null,
+			$loader
+		);
+
 		return $mountPoints;
 	}
 
-	/**
-	 * @return array
-	 */
 	protected function getMultiBucketObjectStore(int $number): array {
 		$config = $this->config->getSystemValue('objectstore_multibucket');
 
@@ -99,4 +118,30 @@ class ObjectStorePreviewCacheMountProvider implements IRootMountProvider {
 
 		return $config['arguments'];
 	}
+
+	protected function getMultiBucketObjectStoreForRoot(): array {
+		$config = $this->config->getSystemValue('objectstore_multibucket');
+
+		// sanity checks
+		if (empty($config['class'])) {
+			$this->logger->error('No class given for objectstore', ['app' => 'files']);
+		}
+		if (!isset($config['arguments'])) {
+			$config['arguments'] = [];
+		}
+
+		/*
+		 * Use any provided bucket argument as prefix
+		 * and add the mapping from parent/child => bucket
+		 */
+		if (!isset($config['arguments']['bucket'])) {
+			$config['arguments']['bucket'] = '';
+		}
+		$config['arguments']['bucket'] .= '0';
+
+		// instantiate object store implementation
+		$config['arguments']['objectstore'] = new $config['class']($config['arguments']);
+
+		return $config['arguments'];
+	}
 }

lib/private/Preview/Storage/Root.php

@@ -40,6 +40,17 @@ class Root extends AppData {
 	public function getFolder(string $name): ISimpleFolder {
 		$internalFolder = $this->getInternalFolder($name);
 
+		try {
+			return parent::getFolder('old-multibucket/' . $internalFolder);
+		} catch (NotFoundException $e) {
+			// not in multibucket fallback #1
+		}
+		try {
+			return parent::getFolder('old-multibucket/' . $name);
+		} catch (NotFoundException $e) {
+			// not in multibucket fallback #2
+		}
+
 		try {
 			return parent::getFolder($internalFolder);
 		} catch (NotFoundException $e) {

tests/lib/Files/Mount/ObjectStorePreviewCacheMountProviderTest.php

@@ -0,0 +1,106 @@
+<?php
+
+declare(strict_types=1);
+/**
+ * @copyright Copyright (c) 2020, Morris Jobke <hey@morrisjobke.de>
+ *
+ * @author Morris Jobke <hey@morrisjobke.de>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 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 Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+namespace Test\Files\Mount;
+
+use OC\Files\Mount\ObjectStorePreviewCacheMountProvider;
+use OC\Files\ObjectStore\S3;
+use OC\Files\Storage\StorageFactory;
+use OCP\Files\Storage\IStorageFactory;
+use OCP\IConfig;
+use OCP\ILogger;
+use PHPUnit\Framework\MockObject\MockObject;
+
+/**
+ * @group DB
+ *
+ * The DB permission is needed for the fake root storage initialization
+ */
+class ObjectStorePreviewCacheMountProviderTest extends \Test\TestCase {
+
+	/** @var ObjectStorePreviewCacheMountProvider */
+	protected $provider;
+
+	/** @var ILogger|MockObject */
+	protected $logger;
+	/** @var IConfig|MockObject */
+	protected $config;
+	/** @var IStorageFactory|MockObject */
+	protected $loader;
+
+
+	protected function setUp(): void {
+		parent::setUp();
+
+		$this->logger = $this->createMock(ILogger::class);
+		$this->config = $this->createMock(IConfig::class);
+		$this->loader = $this->createMock(StorageFactory::class);
+
+		$this->provider = new ObjectStorePreviewCacheMountProvider($this->logger, $this->config);
+	}
+
+	public function testNoMultibucketObjectStorage() {
+		$this->config->expects($this->once())
+			->method('getSystemValue')
+			->with('objectstore_multibucket')
+			->willReturn(null);
+
+		$this->assertEquals([], $this->provider->getRootMounts($this->loader));
+	}
+
+	public function testMultibucketObjectStorage() {
+		$this->config->expects($this->any())
+			->method('getSystemValue')
+			->with('objectstore_multibucket')
+			->willReturn([
+				'class' => S3::class,
+				'arguments' => [
+					'bucket' => 'abc',
+					'num_buckets' => 64,
+					'key' => 'KEY',
+					'secret' => 'SECRET',
+					'hostname' => 'IP',
+					'port' => 'PORT',
+					'use_ssl' => false,
+					'use_path_style' => true,
+				],
+			]);
+		$this->config->expects($this->once())
+			->method('getSystemValueString')
+			->with('instanceid')
+			->willReturn('INSTANCEID');
+
+		$mounts = $this->provider->getRootMounts($this->loader);
+
+		// 256 mounts for the subfolders and 1 for the fake root
+		$this->assertCount(257, $mounts);
+
+		// do some sanity checks if they have correct mount point paths
+		$this->assertEquals('/appdata_INSTANCEID/preview/0/0/', $mounts[0]->getMountPoint());
+		$this->assertEquals('/appdata_INSTANCEID/preview/2/5/', $mounts[37]->getMountPoint());
+		// also test the path of the fake bucket
+		$this->assertEquals('/appdata_INSTANCEID/preview/old-multibucket/', $mounts[256]->getMountPoint());
+	}
+}