Files
nextcloud-ng_backup/lib/Service/LeaseService.php
T
dillard 807353cbe4 Wire Psalm into CI, fix a real bug it found in user-migration import
RepositoryImportSource::copyToFolder() called putContent() on the generic
return type of Node::get(), which doesn't declare that method -- only
File does. Existing-file overwrite during a per-user restore would have
fatally errored at runtime; added an instanceof check and a resource leak
fix (finally-close) while there. Also guarded getFileAsStream() against
fopen() returning false.

Everything else Psalm (strict level) currently flags is mechanical
(missing `final` on leaf classes -- applied everywhere safe) or pre-existing
array-shape/type gaps, captured in psalm-baseline.xml so CI fails only on
new issues from here on, not the whole backlog at once.
2026-10-05 11:45:37 +02:00

89 lines
3.0 KiB
PHP

<?php
declare(strict_types=1);
// SPDX-FileCopyrightText: 2026 Dillard Blom
// SPDX-License-Identifier: AGPL-3.0-or-later
namespace OCA\NgBackup\Service;
use OCP\IDBConnection;
use OCP\Lock\ILockingProvider;
use OCP\Lock\LockedException;
/**
* Shared/exclusive leases with an expiry, stored in ngb_leases.
*
* Nextcloud's locks live up to an hour; a PHP process killed while holding one (web cron time
* limit, OOM, kill -9) would block a location that long. A lease expires on its own unless its
* holder keeps refreshing it. Nextcloud's lock is only held for the few milliseconds in which a
* lease is checked and written.
*/
final class LeaseService {
public const SHARED = 's';
public const EXCLUSIVE = 'x';
public function __construct(
private IDBConnection $db,
private ILockingProvider $locking,
) {
}
/** @return string lease id; throws LockedException when it conflicts with a live lease */
public function acquire(string $name, string $mode, int $ttl): string {
$guard = 'ng_backup/lease/' . $name;
$this->locking->acquireLock($guard, ILockingProvider::LOCK_EXCLUSIVE);
try {
$now = time();
$qb = $this->db->getQueryBuilder();
$qb->delete('ngb_leases')
->where($qb->expr()->eq('name', $qb->createNamedParameter($name)))
->andWhere($qb->expr()->lt('expires_at', $qb->createNamedParameter($now)));
$qb->executeStatement();
$qb = $this->db->getQueryBuilder();
$qb->select('mode')->from('ngb_leases')->where($qb->expr()->eq('name', $qb->createNamedParameter($name)));
$modes = $qb->executeQuery()->fetchAll(\PDO::FETCH_COLUMN);
if ($modes !== [] && ($mode === self::EXCLUSIVE || in_array(self::EXCLUSIVE, $modes, true))) {
throw new LockedException($name);
}
$id = bin2hex(random_bytes(16));
$qb = $this->db->getQueryBuilder();
$qb->insert('ngb_leases')->values([
'id' => $qb->createNamedParameter($id),
'name' => $qb->createNamedParameter($name),
'mode' => $qb->createNamedParameter($mode),
'expires_at' => $qb->createNamedParameter($now + $ttl),
]);
$qb->executeStatement();
return $id;
} finally {
$this->locking->releaseLock($guard, ILockingProvider::LOCK_EXCLUSIVE);
}
}
/** Extend a lease while its holder is still working. */
public function refresh(string $id, int $ttl): void {
$qb = $this->db->getQueryBuilder();
$qb->update('ngb_leases')->set('expires_at', $qb->createNamedParameter(time() + $ttl))
->where($qb->expr()->eq('id', $qb->createNamedParameter($id)));
$qb->executeStatement();
}
public function release(string $id): void {
$qb = $this->db->getQueryBuilder();
$qb->delete('ngb_leases')->where($qb->expr()->eq('id', $qb->createNamedParameter($id)));
$qb->executeStatement();
}
/** Run $fn under a lease; $refresh() can be called during long work. */
public function with(string $name, string $mode, int $ttl, callable $fn): mixed {
$id = $this->acquire($name, $mode, $ttl);
try {
return $fn(fn () => $this->refresh($id, $ttl));
} finally {
$this->release($id);
}
}
}