|
1
|
|
|
<?php |
|
2
|
|
|
|
|
3
|
|
|
namespace RemiSan\Lock\Locker; |
|
4
|
|
|
|
|
5
|
|
|
use RemiSan\Lock\LockStore; |
|
6
|
|
|
use RemiSan\Lock\Exceptions\LockingException; |
|
7
|
|
|
use RemiSan\Lock\Exceptions\UnlockingException; |
|
8
|
|
|
use RemiSan\Lock\Lock; |
|
9
|
|
|
use RemiSan\Lock\Locker; |
|
10
|
|
|
use RemiSan\Lock\TokenGenerator; |
|
11
|
|
|
use Symfony\Component\Stopwatch\Stopwatch; |
|
12
|
|
|
|
|
13
|
|
|
final class SingleStoreLocker implements Locker |
|
14
|
|
|
{ |
|
15
|
|
|
/** @var LockStore */ |
|
16
|
|
|
private $store; |
|
17
|
|
|
|
|
18
|
|
|
/** @var TokenGenerator */ |
|
19
|
|
|
private $tokenGenerator; |
|
20
|
|
|
|
|
21
|
|
|
/** @var Stopwatch */ |
|
22
|
|
|
private $stopwatch; |
|
23
|
|
|
|
|
24
|
|
|
/** |
|
25
|
|
|
* SingleStoreLocker constructor. |
|
26
|
|
|
* |
|
27
|
|
|
* @param LockStore $store The persisting store for the locks |
|
28
|
|
|
* @param TokenGenerator $tokenGenerator The token generator |
|
29
|
|
|
* @param Stopwatch $stopwatch A way to measure time passed |
|
30
|
|
|
*/ |
|
31
|
|
|
public function __construct( |
|
32
|
|
|
$store, |
|
33
|
|
|
TokenGenerator $tokenGenerator, |
|
34
|
|
|
Stopwatch $stopwatch |
|
35
|
|
|
) { |
|
36
|
|
|
$this->store = $store; |
|
37
|
|
|
$this->tokenGenerator = $tokenGenerator; |
|
38
|
|
|
$this->stopwatch = $stopwatch; |
|
39
|
|
|
} |
|
40
|
|
|
|
|
41
|
|
|
/** |
|
42
|
|
|
* {@inheritdoc} |
|
43
|
|
|
*/ |
|
44
|
|
|
public function lock($resource, $ttl = null, $retryDelay = 0, $retryCount = 0) |
|
45
|
|
|
{ |
|
46
|
|
|
$lock = new Lock((string) $resource, $this->tokenGenerator->generateToken()); |
|
47
|
|
|
|
|
48
|
|
|
$tried = 0; |
|
49
|
|
|
while (true) { |
|
50
|
|
|
try { |
|
51
|
|
|
return $this->lockAndCheckQuorumAndTtl($lock, $ttl); |
|
52
|
|
|
} catch (LockingException $e) { |
|
|
|
|
|
|
53
|
|
|
} |
|
54
|
|
|
|
|
55
|
|
|
if ($tried++ === $retryCount) { |
|
56
|
|
|
break; |
|
57
|
|
|
} |
|
58
|
|
|
|
|
59
|
|
|
$this->waitBeforeRetrying($retryDelay); |
|
60
|
|
|
} |
|
61
|
|
|
|
|
62
|
|
|
throw new LockingException('Failed locking the resource.'); |
|
63
|
|
|
} |
|
64
|
|
|
|
|
65
|
|
|
/** |
|
66
|
|
|
* {@inheritdoc} |
|
67
|
|
|
*/ |
|
68
|
|
|
public function isLocked($resource) |
|
69
|
|
|
{ |
|
70
|
|
|
return $this->store->exists((string) $resource); |
|
71
|
|
|
} |
|
72
|
|
|
|
|
73
|
|
|
/** |
|
74
|
|
|
* {@inheritdoc} |
|
75
|
|
|
*/ |
|
76
|
|
|
public function unlock(Lock $lock) |
|
77
|
|
|
{ |
|
78
|
|
|
if (!$this->store->delete($lock)) { |
|
79
|
|
|
if ($this->store->exists($lock->getResource())) { |
|
80
|
|
|
// Only throw an exception if the lock is still present |
|
81
|
|
|
throw new UnlockingException('Failed releasing the lock.'); |
|
82
|
|
|
} |
|
83
|
|
|
} |
|
84
|
|
|
} |
|
85
|
|
|
|
|
86
|
|
|
/** |
|
87
|
|
|
* Try locking resource on store. |
|
88
|
|
|
* |
|
89
|
|
|
* Measure the time to do it and reject if time to lock on store have exceeded the ttl. |
|
90
|
|
|
* |
|
91
|
|
|
* @param Lock $lock The lock instance |
|
92
|
|
|
* @param int $ttl Time to live in milliseconds |
|
93
|
|
|
* |
|
94
|
|
|
* @throws LockingException |
|
95
|
|
|
* |
|
96
|
|
|
* @return Lock |
|
97
|
|
|
*/ |
|
98
|
|
|
private function lockAndCheckQuorumAndTtl(Lock $lock, $ttl) |
|
99
|
|
|
{ |
|
100
|
|
|
$timeMeasure = $this->stopwatch->start($lock->getToken()); |
|
101
|
|
|
$this->store->set($lock, $ttl); |
|
102
|
|
|
$timeMeasure->stop(); |
|
103
|
|
|
|
|
104
|
|
|
if ($ttl) { |
|
105
|
|
|
$this->checkTtl($timeMeasure->getDuration(), $ttl); |
|
106
|
|
|
$lock->setValidityEndTime($timeMeasure->getOrigin() + $ttl); |
|
107
|
|
|
} |
|
108
|
|
|
|
|
109
|
|
|
return $lock; |
|
110
|
|
|
} |
|
111
|
|
|
|
|
112
|
|
|
/** |
|
113
|
|
|
* Make the script wait before retrying to lock. |
|
114
|
|
|
* |
|
115
|
|
|
* @param int $retryDelay The retry delay in milliseconds |
|
116
|
|
|
*/ |
|
117
|
|
|
private function waitBeforeRetrying($retryDelay) |
|
118
|
|
|
{ |
|
119
|
|
|
usleep($retryDelay * 1000); |
|
120
|
|
|
} |
|
121
|
|
|
|
|
122
|
|
|
/** |
|
123
|
|
|
* Checks if the elapsed time is inferior to the ttl. |
|
124
|
|
|
* |
|
125
|
|
|
* To the elapsed time is added a drift time to have a margin of error. |
|
126
|
|
|
* If this adjusted time is greater than the ttl, it will throw a LockingException. |
|
127
|
|
|
* |
|
128
|
|
|
* @param int $elapsedTime The time elapsed in milliseconds |
|
129
|
|
|
* @param int $ttl The time to live in milliseconds |
|
130
|
|
|
* |
|
131
|
|
|
* @throws LockingException |
|
132
|
|
|
*/ |
|
133
|
|
|
private function checkTtl($elapsedTime, $ttl) |
|
134
|
|
|
{ |
|
135
|
|
|
$adjustedElapsedTime = $elapsedTime + $this->store->getDrift($ttl); |
|
136
|
|
|
|
|
137
|
|
|
if ($adjustedElapsedTime >= $ttl) { |
|
138
|
|
|
throw new LockingException('Time to lock the resource has exceeded the ttl.'); |
|
139
|
|
|
} |
|
140
|
|
|
} |
|
141
|
|
|
} |
|
142
|
|
|
|
remi-san /
lock
Loading history...