[Semaphore] Add a semaphore store based on locks #59202
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…aseLocks correctly on failing semphore acquired
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@jderusse if you have some free time maybe you can have a relook at the changes we did since your last review as you are I think most familiar with semaphore component. |
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@jderusse what I'm stuck of how we can make the framework bundle integration for this. |
| @@ -24,7 +24,8 @@ | |||
| "psr/log": "^1|^2|^3" | |||
| }, | |||
| "require-dev": { | |||
| "predis/predis": "^1.1|^2.0" | |||
| "predis/predis": "^1.1|^2.0", | |||
| "symfony/lock": "^5.4 || ^6.0 || ^7.0" | |||
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do we really want to allow those old versions here?
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We can change to everything the core team wants. Currently it works on this versions and I started with the 5.4 as its still supported LTS until 2029.
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I really like this proposal! Is @jderusse's feedback to #59202 (comment) the only blocker? |
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Yes would be nice to get some feedback from @jderusse specially not sure how we can create the And the new framework:
lock: '%env(LOCK_DSN)%'
semaphore: 'lock://'but doesn't work aslong as the factories are static methods. |
| private function createLocks(Key $key, float $ttlInSecond): array | ||
| { | ||
| $locks = []; | ||
| $lockName = base64_encode($key->__toString()); |
| for ($i = 0; $i < $limit; ++$i) { | ||
| $index = ($startPoint + $i) % $limit; | ||
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| $lock = $this->lockFactory->createLock($lockName.'_'.$index, $ttlInSecond, false); |
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if you disable the auto-release feature, you should wrap this function in a try/catch to release locks in case of an exception (ie. network error)
| private function releaseLocks(array $locks, Key $key): void | ||
| { | ||
| foreach ($locks as $lock) { | ||
| $lock->release(); |
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wrap in a try/catch in case one release fails?
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| $locks = $this->createLocks($key, $ttlInSecond); | ||
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| $key->setState(__CLASS__, $locks); |
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we might need to implement the markUnserializable (like we do for LOck) to prevent people from serializing such key.
| { | ||
| $locks = $this->getExistingLocks($key); | ||
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| if (\count($locks) === $key->getWeight()) { |
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should we use === or >= ? I know the createLock method stops when the counters match, and this code is enough.
But what if by "chance" we acquire MORE lock than necessary? ie. for whatever reason, the value in getWeight is dynamic.
IMHO, it doesn't hurt readability to use if (\count($locks) >= $key->getWeight()) (here and bellow,) but it makes the code stronger.
| if ($lock->isExpired()) { | ||
| $this->releaseLocks($locks, $key); | ||
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| throw new SemaphoreExpiredException($key, 'One or multiple locks are already expired.'); |
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The lock component doesn't throw in such situations, it just try to re-acquire the lock. 🤷
I really liked the idea of a semaphore component but not have the possibility to use it without Redis it did not get a lot a drive and usage in our projects and we workaround using Locks.
So this idea did come up to have a Semaphore store which can use the existing lock component for it.
@lyrixx @jderusse