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feat(preview): Expire previews #55632

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b41d19a
chore(PreviewMapper): Remove unused and broken deleteAll method
provokateurin Oct 8, 2025
fee65e5
feat(preview): Expire previews
provokateurin Oct 8, 2025
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8 changes: 8 additions & 0 deletions config/config.sample.php
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Original file line number Diff line number Diff line change
Expand Up @@ -2775,4 +2775,12 @@
* Defaults to ``true``
*/
'enable_lazy_objects' => true,

/**
* Delete previews older than a certain number of days to reduce storage usage.
* Less than one day is not allowed, so set it to 0 to disable the deletion.
*
* Defaults to ``0``.
*/
'preview_expiration_days' => 0,
];
38 changes: 38 additions & 0 deletions core/BackgroundJobs/ExpirePreviewsJob.php
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@@ -0,0 +1,38 @@
<?php

declare(strict_types=1);

/*
* SPDX-FileCopyrightText: 2025 Nextcloud GmbH and Nextcloud contributors
* SPDX-License-Identifier: AGPL-3.0-or-later
*/

namespace OC\Core\BackgroundJobs;

use OC\Preview\PreviewService;
use OCP\AppFramework\Utility\ITimeFactory;
use OCP\BackgroundJob\IJob;
use OCP\BackgroundJob\TimedJob;
use OCP\IConfig;

class ExpirePreviewsJob extends TimedJob {
public function __construct(
ITimeFactory $time,
private readonly IConfig $config,
private readonly PreviewService $service,
) {
parent::__construct($time);

$this->setTimeSensitivity(IJob::TIME_INSENSITIVE);
$this->setInterval(60 * 60 * 24);
}

protected function run($argument): void {
$days = $this->config->getSystemValueInt('preview_expiration_days');
if ($days <= 0) {
return;
}

$this->service->deleteExpiredPreviews($days);
}
}
1 change: 1 addition & 0 deletions lib/composer/composer/autoload_classmap.php
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Expand Up @@ -1248,6 +1248,7 @@
'OC\\Core\\BackgroundJobs\\BackgroundCleanupUpdaterBackupsJob' => $baseDir . '/core/BackgroundJobs/BackgroundCleanupUpdaterBackupsJob.php',
'OC\\Core\\BackgroundJobs\\CheckForUserCertificates' => $baseDir . '/core/BackgroundJobs/CheckForUserCertificates.php',
'OC\\Core\\BackgroundJobs\\CleanupLoginFlowV2' => $baseDir . '/core/BackgroundJobs/CleanupLoginFlowV2.php',
'OC\\Core\\BackgroundJobs\\ExpirePreviewsJob' => $baseDir . '/core/BackgroundJobs/ExpirePreviewsJob.php',
'OC\\Core\\BackgroundJobs\\GenerateMetadataJob' => $baseDir . '/core/BackgroundJobs/GenerateMetadataJob.php',
'OC\\Core\\BackgroundJobs\\LookupServerSendCheckBackgroundJob' => $baseDir . '/core/BackgroundJobs/LookupServerSendCheckBackgroundJob.php',
'OC\\Core\\BackgroundJobs\\MovePreviewJob' => $baseDir . '/core/BackgroundJobs/MovePreviewJob.php',
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1 change: 1 addition & 0 deletions lib/composer/composer/autoload_static.php
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Expand Up @@ -1289,6 +1289,7 @@ class ComposerStaticInit749170dad3f5e7f9ca158f5a9f04f6a2
'OC\\Core\\BackgroundJobs\\BackgroundCleanupUpdaterBackupsJob' => __DIR__ . '/../../..' . '/core/BackgroundJobs/BackgroundCleanupUpdaterBackupsJob.php',
'OC\\Core\\BackgroundJobs\\CheckForUserCertificates' => __DIR__ . '/../../..' . '/core/BackgroundJobs/CheckForUserCertificates.php',
'OC\\Core\\BackgroundJobs\\CleanupLoginFlowV2' => __DIR__ . '/../../..' . '/core/BackgroundJobs/CleanupLoginFlowV2.php',
'OC\\Core\\BackgroundJobs\\ExpirePreviewsJob' => __DIR__ . '/../../..' . '/core/BackgroundJobs/ExpirePreviewsJob.php',
'OC\\Core\\BackgroundJobs\\GenerateMetadataJob' => __DIR__ . '/../../..' . '/core/BackgroundJobs/GenerateMetadataJob.php',
'OC\\Core\\BackgroundJobs\\LookupServerSendCheckBackgroundJob' => __DIR__ . '/../../..' . '/core/BackgroundJobs/LookupServerSendCheckBackgroundJob.php',
'OC\\Core\\BackgroundJobs\\MovePreviewJob' => __DIR__ . '/../../..' . '/core/BackgroundJobs/MovePreviewJob.php',
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15 changes: 9 additions & 6 deletions lib/private/Preview/Db/PreviewMapper.php
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Expand Up @@ -9,6 +9,8 @@

namespace OC\Preview\Db;

use DateInterval;
use DateTimeImmutable;
use OCP\AppFramework\Db\Entity;
use OCP\AppFramework\Db\QBMapper;
use OCP\DB\Exception;
Expand All @@ -25,6 +27,7 @@ class PreviewMapper extends QBMapper {
private const TABLE_NAME = 'previews';
private const LOCATION_TABLE_NAME = 'preview_locations';
private const VERSION_TABLE_NAME = 'preview_versions';
public const MAX_CHUNK_SIZE = 1000;

public function __construct(
IDBConnection $db,
Expand Down Expand Up @@ -168,19 +171,19 @@ public function getLocationId(string $bucket, string $objectStore): int {
}
}

public function deleteAll(): void {
$delete = $this->db->getQueryBuilder();
$delete->delete($this->getTableName());
}

/**
* @return \Generator<Preview>
*/
public function getPreviews(int $lastId, int $limit = 1000): \Generator {
public function getPreviews(int $lastId, int $limit = self::MAX_CHUNK_SIZE, ?int $maxAgeDays = null): \Generator {
$qb = $this->db->getQueryBuilder();
$this->joinLocation($qb)
->where($qb->expr()->gt('p.id', $qb->createNamedParameter($lastId, IQueryBuilder::PARAM_INT)))
->setMaxResults($limit);

if ($maxAgeDays !== null) {
$qb->andWhere($qb->expr()->lt('mtime', $qb->createNamedParameter((new DateTimeImmutable())->sub(new DateInterval('P' . $maxAgeDays . 'D'))->getTimestamp(), IQueryBuilder::PARAM_INT)));
}

return $this->yieldEntities($qb);

}
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21 changes: 19 additions & 2 deletions lib/private/Preview/PreviewService.php
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Expand Up @@ -85,15 +85,15 @@ public function getPreviewsForMimeTypes(array $mimeTypes): \Generator {
public function deleteAll(): void {
$lastId = 0;
while (true) {
$previews = $this->previewMapper->getPreviews($lastId, 1000);
$previews = $this->previewMapper->getPreviews($lastId, PreviewMapper::MAX_CHUNK_SIZE);
$i = 0;
foreach ($previews as $preview) {
$this->deletePreview($preview);
$i++;
$lastId = $preview->getId();
}

if ($i !== 1000) {
if ($i !== PreviewMapper::MAX_CHUNK_SIZE) {
break;
}
}
Expand All @@ -106,4 +106,21 @@ public function deleteAll(): void {
public function getAvailablePreviews(array $fileIds): array {
return $this->previewMapper->getAvailablePreviews($fileIds);
}

public function deleteExpiredPreviews(int $maxAgeDays): void {
$lastId = 0;
while (true) {
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@tcitworld tcitworld Oct 9, 2025

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Why do everything at once? If an admin suddenly sets preview_expiration_days to a very low value, there will need a lot of work to delete everything, so the cron might timeout at some point.

The fact that the background job runs regularly should be enough to lower the number of previews little by little. And we can also add a command to cleanup everything that won't be limited if needed.

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@provokateurin provokateurin Oct 9, 2025

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Sure, but if it is limited to some value per run, then the job might not be able to catch up with deleting all expired previews.

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@tcitworld tcitworld Oct 9, 2025

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Sensitive defaults should be acceptable. Maybe increase the job frequency to make sure this works?

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@CarlSchwan CarlSchwan Oct 9, 2025 •
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A common pattern we have elsewhere is to limit by time. e.g. max 1 hour running

$startTime = time();
		while (true) {
			$done = $this->doTheStuffWithLimit(1000);

                        if ($done) {
                            break;
                        }

			// Stop if execution time is more than one hour.
			if (time() - $startTime > 3600) {
				return;
			}

$previews = $this->previewMapper->getPreviews($lastId, PreviewMapper::MAX_CHUNK_SIZE, $maxAgeDays);
$i = 0;
foreach ($previews as $preview) {
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@CarlSchwan CarlSchwan Oct 9, 2025

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It might make sense to wrap this in a transation and delete by chunk to speed up a bit the process

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@provokateurin provokateurin Oct 9, 2025

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You're right, I just copied from the deleteAll method which doesn't have that (probably because it will only be used by tests?)

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@CarlSchwan CarlSchwan Oct 9, 2025

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Yes, it's currently only used in tests

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@provokateurin provokateurin Oct 9, 2025 •
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Hm but with a transaction the DB and storage could get out of sync and I don't know how that is handled. What happens if the files are deleted, but the entries are still in the DB?

(Ok they can get out of sync without a transaction as well, but it would be limited to a single preview and not all expired ones)

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@CarlSchwan CarlSchwan Oct 9, 2025 •
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Don't call rollback but just commit if something fails in the middle while removing a preview from the storage?

$this->deletePreview($preview);
$i++;
$lastId = $preview->getId();
}

if ($i !== PreviewMapper::MAX_CHUNK_SIZE) {
break;
}
}
}
}
2 changes: 2 additions & 0 deletions lib/private/Setup.php
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Expand Up @@ -14,6 +14,7 @@
use InvalidArgumentException;
use OC\Authentication\Token\PublicKeyTokenProvider;
use OC\Authentication\Token\TokenCleanupJob;
use OC\Core\BackgroundJobs\ExpirePreviewsJob;
use OC\Core\BackgroundJobs\GenerateMetadataJob;
use OC\Core\BackgroundJobs\MovePreviewJob;
use OC\Log\Rotate;
Expand Down Expand Up @@ -507,6 +508,7 @@ public static function installBackgroundJobs(): void {
$jobList->add(CleanupDeletedUsers::class);
$jobList->add(GenerateMetadataJob::class);
$jobList->add(MovePreviewJob::class);
$jobList->add(ExpirePreviewsJob::class);
}

/**
Expand Down
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