LockRegistry.php
7.0 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
<?php
/*
* This file is part of the Symfony package.
*
* (c) Fabien Potencier <fabien@symfony.com>
*
* For the full copyright and license information, please view the LICENSE
* file that was distributed with this source code.
*/
namespace Symfony\Component\Cache;
use Psr\Log\LoggerInterface;
use Symfony\Contracts\Cache\CacheInterface;
use Symfony\Contracts\Cache\ItemInterface;
/**
* LockRegistry is used internally by existing adapters to protect against cache stampede.
*
* It does so by wrapping the computation of items in a pool of locks.
* Foreach each apps, there can be at most 20 concurrent processes that
* compute items at the same time and only one per cache-key.
*
* @author Nicolas Grekas <p@tchwork.com>
*/
final class LockRegistry
{
private static $openedFiles = [];
private static $lockedFiles;
private static $signalingException;
private static $signalingCallback;
/**
* The number of items in this list controls the max number of concurrent processes.
*/
private static $files = [
__DIR__.\DIRECTORY_SEPARATOR.'Adapter'.\DIRECTORY_SEPARATOR.'AbstractAdapter.php',
__DIR__.\DIRECTORY_SEPARATOR.'Adapter'.\DIRECTORY_SEPARATOR.'AbstractTagAwareAdapter.php',
__DIR__.\DIRECTORY_SEPARATOR.'Adapter'.\DIRECTORY_SEPARATOR.'AdapterInterface.php',
__DIR__.\DIRECTORY_SEPARATOR.'Adapter'.\DIRECTORY_SEPARATOR.'ApcuAdapter.php',
__DIR__.\DIRECTORY_SEPARATOR.'Adapter'.\DIRECTORY_SEPARATOR.'ArrayAdapter.php',
__DIR__.\DIRECTORY_SEPARATOR.'Adapter'.\DIRECTORY_SEPARATOR.'ChainAdapter.php',
__DIR__.\DIRECTORY_SEPARATOR.'Adapter'.\DIRECTORY_SEPARATOR.'CouchbaseBucketAdapter.php',
__DIR__.\DIRECTORY_SEPARATOR.'Adapter'.\DIRECTORY_SEPARATOR.'CouchbaseCollectionAdapter.php',
__DIR__.\DIRECTORY_SEPARATOR.'Adapter'.\DIRECTORY_SEPARATOR.'DoctrineAdapter.php',
__DIR__.\DIRECTORY_SEPARATOR.'Adapter'.\DIRECTORY_SEPARATOR.'DoctrineDbalAdapter.php',
__DIR__.\DIRECTORY_SEPARATOR.'Adapter'.\DIRECTORY_SEPARATOR.'FilesystemAdapter.php',
__DIR__.\DIRECTORY_SEPARATOR.'Adapter'.\DIRECTORY_SEPARATOR.'FilesystemTagAwareAdapter.php',
__DIR__.\DIRECTORY_SEPARATOR.'Adapter'.\DIRECTORY_SEPARATOR.'MemcachedAdapter.php',
__DIR__.\DIRECTORY_SEPARATOR.'Adapter'.\DIRECTORY_SEPARATOR.'NullAdapter.php',
__DIR__.\DIRECTORY_SEPARATOR.'Adapter'.\DIRECTORY_SEPARATOR.'ParameterNormalizer.php',
__DIR__.\DIRECTORY_SEPARATOR.'Adapter'.\DIRECTORY_SEPARATOR.'PdoAdapter.php',
__DIR__.\DIRECTORY_SEPARATOR.'Adapter'.\DIRECTORY_SEPARATOR.'PhpArrayAdapter.php',
__DIR__.\DIRECTORY_SEPARATOR.'Adapter'.\DIRECTORY_SEPARATOR.'PhpFilesAdapter.php',
__DIR__.\DIRECTORY_SEPARATOR.'Adapter'.\DIRECTORY_SEPARATOR.'ProxyAdapter.php',
__DIR__.\DIRECTORY_SEPARATOR.'Adapter'.\DIRECTORY_SEPARATOR.'Psr16Adapter.php',
__DIR__.\DIRECTORY_SEPARATOR.'Adapter'.\DIRECTORY_SEPARATOR.'RedisAdapter.php',
__DIR__.\DIRECTORY_SEPARATOR.'Adapter'.\DIRECTORY_SEPARATOR.'RedisTagAwareAdapter.php',
__DIR__.\DIRECTORY_SEPARATOR.'Adapter'.\DIRECTORY_SEPARATOR.'TagAwareAdapter.php',
__DIR__.\DIRECTORY_SEPARATOR.'Adapter'.\DIRECTORY_SEPARATOR.'TagAwareAdapterInterface.php',
__DIR__.\DIRECTORY_SEPARATOR.'Adapter'.\DIRECTORY_SEPARATOR.'TraceableAdapter.php',
__DIR__.\DIRECTORY_SEPARATOR.'Adapter'.\DIRECTORY_SEPARATOR.'TraceableTagAwareAdapter.php',
];
/**
* Defines a set of existing files that will be used as keys to acquire locks.
*
* @return array The previously defined set of files
*/
public static function setFiles(array $files): array
{
$previousFiles = self::$files;
self::$files = $files;
foreach (self::$openedFiles as $file) {
if ($file) {
flock($file, \LOCK_UN);
fclose($file);
}
}
self::$openedFiles = self::$lockedFiles = [];
return $previousFiles;
}
public static function compute(callable $callback, ItemInterface $item, bool &$save, CacheInterface $pool, \Closure $setMetadata = null, LoggerInterface $logger = null)
{
if ('\\' === \DIRECTORY_SEPARATOR && null === self::$lockedFiles) {
// disable locking on Windows by default
self::$files = self::$lockedFiles = [];
}
$key = self::$files ? abs(crc32($item->getKey())) % \count(self::$files) : -1;
if ($key < 0 || self::$lockedFiles || !$lock = self::open($key)) {
return $callback($item, $save);
}
self::$signalingException ?? self::$signalingException = unserialize("O:9:\"Exception\":1:{s:16:\"\0Exception\0trace\";a:0:{}}");
self::$signalingCallback ?? self::$signalingCallback = function () { throw self::$signalingException; };
while (true) {
try {
$locked = false;
// race to get the lock in non-blocking mode
$locked = flock($lock, \LOCK_EX | \LOCK_NB, $wouldBlock);
if ($locked || !$wouldBlock) {
$logger && $logger->info(sprintf('Lock %s, now computing item "{key}"', $locked ? 'acquired' : 'not supported'), ['key' => $item->getKey()]);
self::$lockedFiles[$key] = true;
$value = $callback($item, $save);
if ($save) {
if ($setMetadata) {
$setMetadata($item);
}
$pool->save($item->set($value));
$save = false;
}
return $value;
}
// if we failed the race, retry locking in blocking mode to wait for the winner
$logger && $logger->info('Item "{key}" is locked, waiting for it to be released', ['key' => $item->getKey()]);
flock($lock, \LOCK_SH);
} finally {
flock($lock, \LOCK_UN);
unset(self::$lockedFiles[$key]);
}
try {
$value = $pool->get($item->getKey(), self::$signalingCallback, 0);
$logger && $logger->info('Item "{key}" retrieved after lock was released', ['key' => $item->getKey()]);
$save = false;
return $value;
} catch (\Exception $e) {
if (self::$signalingException !== $e) {
throw $e;
}
$logger && $logger->info('Item "{key}" not found while lock was released, now retrying', ['key' => $item->getKey()]);
}
}
return null;
}
private static function open(int $key)
{
if (null !== $h = self::$openedFiles[$key] ?? null) {
return $h;
}
set_error_handler(function () {});
try {
$h = fopen(self::$files[$key], 'r+');
} finally {
restore_error_handler();
}
return self::$openedFiles[$key] = $h ?: @fopen(self::$files[$key], 'r');
}
}