* 5.2:
µCS fix
CS fix
CS fix
[travis] use PHP 8.0 to patch return types and run deps=low
Add me as a Notifier code owner
Update sl_SI translations
Don't trigger deprecation for deprecated aliases pointing to deprecated definitions
[HttpFoundation] use atomic writes in MockFileSessionStorage
fix typo
Make EmailMessage & SmsMessage transport nullable
remove unused argument
[SecurityBundle] Drop dead check
[DI] fix param annotation
[SecurityBundle] Remove invalid service definition
[Config] Add \Symfony\Component\Config\Loader::load() return type
Simplify PHP CS Fixer config
Rename normalize param
* 5.2:
harden test to not depend on the actual time
[ProxyManager] fix tests
actually compare the order of entries when any sorting is applied
Dump abstract arguments
* 5.1:
harden test to not depend on the actual time
[ProxyManager] fix tests
actually compare the order of entries when any sorting is applied
Dump abstract arguments
This allows us to remove autoload calls that are necessary for the
persistence 1 backwards-compatibility layer to work.
The require-dev constraints on doctrine/orm are bumped to ^2.7.3 because
lower versions are not compatible with doctrine/persistence 2.
* 5.1:
[Process] Dont test TTY if there is no TTY support
Fixing some Mongolian
translating the validators for european portuguese language
Fix CI
Update validators.he.xlf
Update security.he.xlf
Update validators.he.xlf
Improve performances in CircualReference detection
[PHPUnitBridge] Fixed crash on Windows with PHP 8
Fix session called initized several time
That package is being phased out, and there are good chances that the
classes involved at runtime are completely different from the classes
involved in the test changed in that commit. That test was the only
piece of code I could find still referencing the
Doctrine\Common\Reflection namespace.
* 5.1:
fix merge
fix merge
Remove branch-version (keep them for contracts only)
[HttpClient] relax auth bearer format requirements
[PHPUnitBridge] Silence errors from mkdir()
[DependencyInjection] Preload classes with union types correctly.
[Serializer] fix decoding float XML attributes starting with 0
add missing dutch translations
[TwigBridge] Remove "transchoice" from the code base
Support PHPUnit 8 and PHPUnit 9 in constraint compatibility trait
Add expectDeprecation, expectNotice, expectWarning, and expectError to TestCase polyfill
[String] fix before/after[Last]() returning the empty string instead of the original one on non-match
Add missing exporter function for PHPUnit 7
[Validator] Add missing romanian translations
[String] fix slicing in UnicodeString
[Cache] Use correct expiry in ChainAdapter
do not translate null placeholders or titles
* 4.4:
fix merge
Remove branch-version (keep them for contracts only)
[HttpClient] relax auth bearer format requirements
[PHPUnitBridge] Silence errors from mkdir()
[DependencyInjection] Preload classes with union types correctly.
[Serializer] fix decoding float XML attributes starting with 0
add missing dutch translations
Support PHPUnit 8 and PHPUnit 9 in constraint compatibility trait
Add expectDeprecation, expectNotice, expectWarning, and expectError to TestCase polyfill
Add missing exporter function for PHPUnit 7
[Validator] Add missing romanian translations
[Cache] Use correct expiry in ChainAdapter
do not translate null placeholders or titles
* 3.4:
Remove branch-version (keep them for contracts only)
[Serializer] fix decoding float XML attributes starting with 0
add missing dutch translations
[Validator] Add missing romanian translations
do not translate null placeholders or titles
This PR was merged into the 5.2-dev branch.
Discussion
----------
[HttpClient] fix pausing AmpResponse
| Q | A
| ------------- | ---
| Branch? | master
| Bug fix? | yes
| New feature? | no
| Deprecations? | no
| Tickets | None
| License | MIT
| Doc PR | None
This fixes the pause handler while streaming bodies in `AmpHttpClient`.
Needs to be rebased onto the target branch and needs some test fixes. @nicolas-grekas FYI.
Commits
-------
bf2d1cf6e7 Improve pause handler
Few years ago, we have introduced the Lock component. This is a very nice component, but sometime it is not enough. Sometime you need semaphore.
This is why I'm introducing this new component.
From wikipedia:
> In computer science, a semaphore is a variable or abstract data type used to control access to a common resource by multiple processes in a concurrent system such as a multitasking operating system. A semaphore is simply a variable. This variable is used to solve critical section problems and to achieve process synchronization in the multi processing environment. A trivial semaphore is a plain variable that is changed (for example, incremented or decremented, or toggled) depending on programmer-defined conditions.
This new component is more than a variable. This is an abstraction on top of different storage.
To make a quick comparison with a lock:
* A lock allows only 1 process to access a resource;
* A semaphore allow N process to access a resource.
Basically, a lock is a semaphore where `N = 1`.
PHP exposes some `sem_*` functions like [`sem_acquire`](http://php.net/sem_acquire). This module provides wrappers for the System V IPC family of functions. It includes semaphores, shared memory and inter-process messaging (IPC).
The Lock component has a storage that works with theses functions. It uses it with `N = 1`.
Wikipedia has some [examples](https://en.wikipedia.org/wiki/Semaphore_(programming)#Examples)
But I can add one more commun use case.
If you are building an async system that process user data, you may want to priorise all jobs. You can achieve that by running at maximum N jobs per user at the same time. If the user has more resources, you give him more concurrent jobs (so a bigger `N`).
Thanks to semaphores, it's pretty easy to know if a new job can be run.
I'm not saying the following services are using semaphore, but they may solve the previous problematic with semaphores. Here is some examples:
* services like testing platform where a user can test N projects concurrently (travis, circle, appveyor, insight, ...)
* services that ingest lots of data (newrelic, datadog, blackfire, segment.io, ...))
* services that send email in batch (campaign monitor, mailchimp, ...)
* etc...
To do so, since PHP is mono-threaded, you run M PHP workers. And in each worker, you look for for the next job. When you grab a job, you try to acquires a semaphore. If you got it, you process the job. If not you try another job.
FTR in other language, like Go, there are no need to run M workers, one is enough.
```php
<?php
use Symfony\Component\Lock\LockFactory;
use Symfony\Component\Lock\Store\RedisStore as LockRedisStore;
use Symfony\Component\Semaphore\SemaphoreFactory;
use Symfony\Component\Semaphore\Store\RedisStore;
require __DIR__.'/vendor/autoload.php';
$redis = new Redis();
$redis->connect('172.17.0.2');
// Internally, Semaphore needs a lock
$lock = (new LockFactory(new LockRedisStore($redis)))->createLock('test:lock', 1);
// Create a semaphore:
// * name = test
// * limit = 3 (it means only 3 process are allowed)
// * ttl = 10 seconds : Maximum expected semaphore duration in seconds
$semaphore = (new SemaphoreFactory($lock, new RedisStore($redis)))->createSemaphore('test', 3, 10);
if (!$semaphore->acquire()) {
echo "Could not acquire the semaphore\n";
exit(1);
}
// The semaphore has been acquired
// Do the heavy job
for ($i = 0; $i < 100; ++$i) {
sleep(1);
// Before the expiration, refresh the semaphore if the job is not finished yet
if ($i % 9 === 0) {
$semaphore->refresh();
}
}
// Release it when finished
$semaphore->release();
```
I looked at [packagist](https://packagist.org/?query=semaphore) and:
* most of packages are using a semaphore storage for creating a lock. So there are not relevant here;
* some packages need an async framework to be used (amphp for example);
* the only packages really implementing a semaphore, has a really low code quality and some bugs.
1. I initially copied the Lock component since the external API is quite similar;
1. I simplified it a lot for the current use case;
1. I implemented the RedisStorage according the [redis book](https://redislabs.com/ebook/part-2-core-concepts/chapter-6-application-components-in-redis/6-3-counting-semaphores/;)
1. I forced a TTL on the storage.