Add migration to move over existing storage ids

Signed-off-by: Julius Härtl <jus@bitgrid.net>

apps/files_external/appinfo/info.xml

@@ -9,7 +9,7 @@ This application enables administrators to configure connections to external sto
 
 External storage can be configured using the GUI or at the command line. This second option provides the advanced user with more flexibility for configuring bulk external storage mounts and setting mount priorities. More information is available in the external storage GUI documentation and the external storage Configuration File documentation.
 	</description>
-	<version>1.12.0</version>
+	<version>1.12.1</version>
 	<licence>agpl</licence>
 	<author>Robin Appelman</author>
 	<author>Michael Gapczynski</author>

apps/files_external/lib/Migration/Version1015Date20211104103506.php

@@ -0,0 +1,111 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * @copyright Copyright (c) 2021 Julius Härtl <jus@bitgrid.net>
+ *
+ * @author Julius Härtl <jus@bitgrid.net>
+ *
+ * @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 OCA\Files_External\Migration;
+
+use Closure;
+use OC\Files\Cache\Storage;
+use OCP\DB\Exception;
+use OCP\DB\IResult;
+use OCP\DB\ISchemaWrapper;
+use OCP\IDBConnection;
+use OCP\Migration\IOutput;
+use OCP\Migration\SimpleMigrationStep;
+use Psr\Log\LoggerInterface;
+
+class Version1015Date20211104103506 extends SimpleMigrationStep {
+
+	/** @var IDBConnection */
+	private $connection;
+	/** @var LoggerInterface */
+	private $logger;
+
+	public function __construct(IDBConnection $connection, LoggerInterface $logger) {
+		$this->connection = $connection;
+		$this->logger = $logger;
+	}
+
+	public function postSchemaChange(IOutput $output, Closure $schemaClosure, array $options): ?ISchemaWrapper {
+		$qb = $this->connection->getQueryBuilder();
+		$qb->update('storages')
+			->set('id', $qb->createParameter('newId'))
+			->where($qb->expr()->eq('id', $qb->createParameter('oldId')));
+
+		$mounts = $this->getS3Mounts();
+		if (!$mounts instanceof IResult) {
+			throw new \Exception('Could not fetch existing mounts for migration');
+		}
+
+		while ($mount = $mounts->fetch()) {
+			$config = $this->getStorageConfig((int)$mount['mount_id']);
+			$hostname = $config['hostname'];
+			$bucket = $config['bucket'];
+			$key = $config['key'];
+			$oldId = Storage::adjustStorageId('amazon::' . $bucket);
+			$newId = Storage::adjustStorageId('amazon::external::' . md5($hostname . ':' . $bucket . ':' . $key));
+			try {
+				$qb->setParameter('oldId', $oldId);
+				$qb->setParameter('newId', $newId);
+				$qb->execute();
+				$this->logger->info('Migrated s3 storage id for mount with id ' . $mount['mount_id'] . ' to ' . $newId);
+			} catch (Exception $e) {
+				$this->logger->error('Failed to migrate external s3 storage id for mount with id ' . $mount['mount_id'], [
+					'exception' => $e
+				]);
+			}
+		}
+		return null;
+	}
+
+	/**
+	 * @throws Exception
+	 * @return \OCP\DB\IResult|int
+	 */
+	private function getS3Mounts() {
+		$qb = $this->connection->getQueryBuilder();
+		$qb->select('m.mount_id')
+			->selectAlias('c.value', 'bucket')
+			->from('external_mounts', 'm')
+			->innerJoin('m', 'external_config', 'c', 'c.mount_id = m.mount_id')
+			->where($qb->expr()->eq('m.storage_backend', $qb->createPositionalParameter('amazons3')))
+			->andWhere($qb->expr()->eq('c.key', $qb->createPositionalParameter('bucket')));
+		return $qb->execute();
+	}
+
+	/**
+	 * @throws Exception
+	 */
+	private function getStorageConfig(int $mountId): array {
+		$qb = $this->connection->getQueryBuilder();
+		$qb->select('key', 'value')
+			->from('external_config')
+			->where($qb->expr()->eq('mount_id', $qb->createPositionalParameter($mountId)));
+		$config = [];
+		foreach ($qb->execute()->fetchAll() as $row) {
+			$config[$row['key']] = $row['value'];
+		}
+		return $config;
+	}
+}