[RateLimiter] Added reserve() to LimiterInterface and rename Limiter …

…to RateLimiter
symfony · fabpot · Oct 16, 2020 · Oct 11, 2020 · Oct 16, 2020 · cd34f2125423b6792c175528d90652ff29f525cf
commit cd34f2125423b6792c175528d90652ff29f525cf
diff --git a/src/Symfony/Bundle/FrameworkBundle/DependencyInjection/FrameworkExtension.php b/src/Symfony/Bundle/FrameworkBundle/DependencyInjection/FrameworkExtension.php
@@ -128,8 +128,8 @@
 use Symfony\Component\PropertyInfo\PropertyReadInfoExtractorInterface;
 use Symfony\Component\PropertyInfo\PropertyTypeExtractorInterface;
 use Symfony\Component\PropertyInfo\PropertyWriteInfoExtractorInterface;
-use Symfony\Component\RateLimiter\Limiter;
 use Symfony\Component\RateLimiter\LimiterInterface;
+use Symfony\Component\RateLimiter\RateLimiter;
 use Symfony\Component\RateLimiter\Storage\CacheStorage;
 use Symfony\Component\Routing\Loader\AnnotationDirectoryLoader;
 use Symfony\Component\Routing\Loader\AnnotationFileLoader;
@@ -2266,7 +2266,7 @@ public static function registerRateLimiter(ContainerBuilder $container, string $
         $limiterConfig['id'] = $name;
         $limiter->replaceArgument(0, $limiterConfig);
 
-        $container->registerAliasForArgument($limiterId, Limiter::class, $name.'.limiter');
+        $container->registerAliasForArgument($limiterId, RateLimiter::class, $name.'.limiter');
     }
 
     private function resolveTrustedHeaders(array $headers): int

diff --git a/src/Symfony/Bundle/FrameworkBundle/Resources/config/rate_limiter.php b/src/Symfony/Bundle/FrameworkBundle/Resources/config/rate_limiter.php
@@ -11,15 +11,15 @@
 
 namespace Symfony\Component\DependencyInjection\Loader\Configurator;
 
-use Symfony\Component\RateLimiter\Limiter;
+use Symfony\Component\RateLimiter\RateLimiter;
 
 return static function (ContainerConfigurator $container) {
     $container->services()
         ->set('cache.rate_limiter')
             ->parent('cache.app')
             ->tag('cache.pool')
 
-        ->set('limiter', Limiter::class)
+        ->set('limiter', RateLimiter::class)
             ->abstract()
             ->args([
                 abstract_arg('config'),

diff --git a/...ony/Bundle/SecurityBundle/DependencyInjection/Security/Factory/LoginThrottlingFactory.php b/...ony/Bundle/SecurityBundle/DependencyInjection/Security/Factory/LoginThrottlingFactory.php
@@ -18,7 +18,7 @@
 use Symfony\Component\DependencyInjection\ContainerBuilder;
 use Symfony\Component\DependencyInjection\Reference;
 use Symfony\Component\HttpFoundation\RateLimiter\RequestRateLimiterInterface;
-use Symfony\Component\RateLimiter\Limiter;
+use Symfony\Component\RateLimiter\RateLimiter;
 use Symfony\Component\Security\Http\EventListener\LoginThrottlingListener;
 use Symfony\Component\Security\Http\RateLimiter\DefaultLoginRateLimiter;
 
@@ -63,7 +63,7 @@ public function createAuthenticator(ContainerBuilder $container, string $firewal
             throw new \LogicException('Login throttling requires symfony/security-http:^5.2.');
         }
 
-        if (!class_exists(Limiter::class)) {
+        if (!class_exists(RateLimiter::class)) {
             throw new \LogicException('Login throttling requires symfony/rate-limiter to be installed and enabled.');
         }
 

diff --git a/src/Symfony/Component/RateLimiter/CompoundLimiter.php b/src/Symfony/Component/RateLimiter/CompoundLimiter.php
@@ -11,6 +11,8 @@
 
 namespace Symfony\Component\RateLimiter;
 
+use Symfony\Component\RateLimiter\Exception\ReserveNotSupportedException;
+
 /**
  * @author Wouter de Jong <wouter@wouterj.nl>
  *
@@ -31,6 +33,11 @@ public function __construct(array $limiters)
         $this->limiters = $limiters;
     }
 
+    public function reserve(int $tokens = 1, ?float $maxTime = null): Reservation
+    {
+        throw new ReserveNotSupportedException(__CLASS__);
+    }
+
     public function consume(int $tokens = 1): Limit
     {
         $minimalLimit = null;

diff --git a/src/Symfony/Component/RateLimiter/Exception/MaxWaitDurationExceededException.php b/src/Symfony/Component/RateLimiter/Exception/MaxWaitDurationExceededException.php
@@ -11,11 +11,26 @@
 
 namespace Symfony\Component\RateLimiter\Exception;
 
+use Symfony\Component\RateLimiter\Limit;
+
 /**
  * @author Wouter de Jong <wouter@wouterj.nl>
  *
  * @experimental in 5.2
  */
 class MaxWaitDurationExceededException extends \RuntimeException
 {
+    private $limit;

+    public function __construct(string $message, Limit $limit, int $code = 0, ?\Throwable $previous = null)
+    {
+        parent::__construct($message, $code, $previous);
+
+        $this->limit = $limit;
+    }
+
+    public function getLimit(): Limit
+    {
+        return $this->limit;
+    }
 }
diff --git a/src/Symfony/Component/RateLimiter/Exception/ReserveNotSupportedException.php b/src/Symfony/Component/RateLimiter/Exception/ReserveNotSupportedException.php
@@ -0,0 +1,25 @@
+<?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\RateLimiter\Exception;
+
+/**
+ * @author Wouter de Jong <wouter@wouterj.nl>
+ *
+ * @experimental in 5.2
+ */
+class ReserveNotSupportedException extends \BadMethodCallException
+{
+    public function __construct(string $limiterClass, int $code = 0, ?\Throwable $previous = null)
+    {
+        parent::__construct(sprintf('Reserving tokens is not supported by "%s".', $limiterClass), $code, $previous);
+    }
+}
diff --git a/src/Symfony/Component/RateLimiter/FixedWindowLimiter.php b/src/Symfony/Component/RateLimiter/FixedWindowLimiter.php
@@ -13,6 +13,7 @@
 
 use Symfony\Component\Lock\LockInterface;
 use Symfony\Component\Lock\NoLock;
+use Symfony\Component\RateLimiter\Exception\MaxWaitDurationExceededException;
 use Symfony\Component\RateLimiter\Storage\StorageInterface;
 use Symfony\Component\RateLimiter\Util\TimeUtil;
 
@@ -33,49 +34,72 @@ final class FixedWindowLimiter implements LimiterInterface
 
     public function __construct(string $id, int $limit, \DateInterval $interval, StorageInterface $storage, ?LockInterface $lock = null)
     {
+        if ($limit < 1) {
+            throw new \InvalidArgumentException(sprintf('Cannot set the limit of "%s" to 0, as that would never accept any hit.', __CLASS__));
+        }
+
         $this->storage = $storage;
         $this->lock = $lock ?? new NoLock();
         $this->id = $id;
         $this->limit = $limit;
         $this->interval = TimeUtil::dateIntervalToSeconds($interval);
     }
 
-    /**
-     * {@inheritdoc}
-     */
-    public function consume(int $tokens = 1): Limit
+    public function reserve(int $tokens = 1, ?float $maxTime = null): Reservation
     {
+        if ($tokens > $this->limit) {
+            throw new \InvalidArgumentException(sprintf('Cannot reserve more tokens (%d) than the size of the rate limiter (%d).', $tokens, $this->limit));
+        }
+
         $this->lock->acquire(true);
 
         try {
             $window = $this->storage->fetch($this->id);
             if (!$window instanceof Window) {
-                $window = new Window($this->id, $this->interval);
+                $window = new Window($this->id, $this->interval, $this->limit);
             }
 
-            $hitCount = $window->getHitCount();
-            $availableTokens = $this->getAvailableTokens($hitCount);
-            $windowStart = \DateTimeImmutable::createFromFormat('U', time());
-            if ($availableTokens < $tokens) {
-                return new Limit($availableTokens, $this->getRetryAfter($windowStart), false);
-            }
+            $now = microtime(true);
+            $availableTokens = $window->getAvailableTokens($now);
+            if ($availableTokens >= $tokens) {
+                $window->add($tokens);
 
-            $window->add($tokens);
-            $this->storage->save($window);
+                $reservation = new Reservation($now, new Limit($window->getAvailableTokens($now), \DateTimeImmutable::createFromFormat('U', floor($now)), true));
+            } else {
+                $remainingTokens = $tokens - $availableTokens;
+                $waitDuration = $window->calculateTimeForTokens($remainingTokens);
 
-            return new Limit($this->getAvailableTokens($window->getHitCount()), $this->getRetryAfter($windowStart), true);
+                if (null !== $maxTime && $waitDuration > $maxTime) {
+                    // process needs to wait longer than set interval
+                    throw new MaxWaitDurationExceededException(sprintf('The rate limiter wait time ("%d" seconds) is longer than the provided maximum time ("%d" seconds).', $waitDuration, $maxTime), new Limit($window->getAvailableTokens($now), \DateTimeImmutable::createFromFormat('U', floor($now + $waitDuration)), false));
+                }
+
+                $window->add($tokens);
+
+                $reservation = new Reservation($now + $waitDuration, new Limit($window->getAvailableTokens($now), \DateTimeImmutable::createFromFormat('U', floor($now + $waitDuration)), false));
+            }
+            $this->storage->save($window);
         } finally {
             $this->lock->release();
         }
+
+        return $reservation;
     }
 
-    public function getAvailableTokens(int $hitCount): int
+    /**
+     * {@inheritdoc}
+     */
+    public function consume(int $tokens = 1): Limit
     {
-        return $this->limit - $hitCount;
+        try {
+            return $this->reserve($tokens, 0)->getLimit();
+        } catch (MaxWaitDurationExceededException $e) {
+            return $e->getLimit();
+        }
     }
 
-    private function getRetryAfter(\DateTimeImmutable $windowStart): \DateTimeImmutable
+    public function getAvailableTokens(int $hitCount): int
     {
-        return $windowStart->add(new \DateInterval(sprintf('PT%sS', $this->interval)));
+        return $this->limit - $hitCount;
     }
 }
diff --git a/src/Symfony/Component/RateLimiter/LimiterInterface.php b/src/Symfony/Component/RateLimiter/LimiterInterface.php
@@ -11,13 +11,32 @@
 
 namespace Symfony\Component\RateLimiter;
 
+use Symfony\Component\RateLimiter\Exception\MaxWaitDurationExceededException;
+use Symfony\Component\RateLimiter\Exception\ReserveNotSupportedException;
+
 /**
  * @author Wouter de Jong <wouter@wouterj.nl>
  *
  * @experimental in 5.2
  */
 interface LimiterInterface
 {
+    /**
+     * Waits until the required number of tokens is available.
+     *
+     * The reserved tokens will be taken into account when calculating
+     * future token consumptions. Do not use this method if you intend
+     * to skip this process.
+     *
+     * @param int   $tokens  the number of tokens required
+     * @param float $maxTime maximum accepted waiting time in seconds
+     *
+     * @throws MaxWaitDurationExceededException if $maxTime is set and the process needs to wait longer than its value (in seconds)
+     * @throws ReserveNotSupportedException     if this limiter implementation doesn't support reserving tokens
+     * @throws \InvalidArgumentException        if $tokens is larger than the maximum burst size
+     */
+    public function reserve(int $tokens = 1, ?float $maxTime = null): Reservation;
+
     /**
      * Use this method if you intend to drop if the required number
      * of tokens is unavailable.

diff --git a/src/Symfony/Component/RateLimiter/NoLimiter.php b/src/Symfony/Component/RateLimiter/NoLimiter.php
@@ -23,6 +23,11 @@
  */
 final class NoLimiter implements LimiterInterface
 {
+    public function reserve(int $tokens = 1, ?float $maxTime = null): Reservation
+    {
+        return new Reservation(time(), new Limit(\INF, new \DateTimeImmutable(), true));
+    }
+
     public function consume(int $tokens = 1): Limit
     {
         return new Limit(\INF, new \DateTimeImmutable(), true);

diff --git a/src/Symfony/Component/RateLimiter/README.md b/src/Symfony/Component/RateLimiter/README.md
@@ -18,9 +18,9 @@ $ composer require symfony/rate-limiter
 
 ```php
 use Symfony\Component\RateLimiter\Storage\InMemoryStorage;
-use Symfony\Component\RateLimiter\Limiter;
+use Symfony\Component\RateLimiter\RateLimiter;
 
-$limiter = new Limiter([
+$limiter = new RateLimiter([
     'id' => 'login',
     'strategy' => 'token_bucket', // or 'fixed_window'
     'limit' => 10,

diff --git a/...Symfony/Component/RateLimiter/Limiter.php → ...ony/Component/RateLimiter/RateLimiter.php b/...Symfony/Component/RateLimiter/Limiter.php → ...ony/Component/RateLimiter/RateLimiter.php
@@ -22,7 +22,7 @@
  *
  * @experimental in 5.2
  */
-final class Limiter
+final class RateLimiter
 {
     private $config;
     private $storage;

diff --git a/src/Symfony/Component/RateLimiter/Reservation.php b/src/Symfony/Component/RateLimiter/Reservation.php
@@ -19,13 +19,15 @@
 final class Reservation
 {
     private $timeToAct;
+    private $limit;
 
     /**
      * @param float $timeToAct Unix timestamp in seconds when this reservation should act
      */
-    public function __construct(float $timeToAct)
+    public function __construct(float $timeToAct, Limit $limit)
     {
         $this->timeToAct = $timeToAct;
+        $this->limit = $limit;
     }
 
     public function getTimeToAct(): float
@@ -38,6 +40,11 @@ public function getWaitDuration(): float
         return max(0, (-microtime(true)) + $this->timeToAct);
     }
 
+    public function getLimit(): Limit
+    {
+        return $this->limit;
+    }
+
     public function wait(): void
     {
         usleep($this->getWaitDuration() * 1e6);

diff --git a/src/Symfony/Component/RateLimiter/SlidingWindowLimiter.php b/src/Symfony/Component/RateLimiter/SlidingWindowLimiter.php
@@ -13,6 +13,7 @@
 
 use Symfony\Component\Lock\LockInterface;
 use Symfony\Component\Lock\NoLock;
+use Symfony\Component\RateLimiter\Exception\ReserveNotSupportedException;
 use Symfony\Component\RateLimiter\Storage\StorageInterface;
 use Symfony\Component\RateLimiter\Util\TimeUtil;
 
@@ -67,6 +68,11 @@ public function __construct(string $id, int $limit, \DateInterval $interval, Sto
         $this->interval = TimeUtil::dateIntervalToSeconds($interval);
     }
 
+    public function reserve(int $tokens = 1, ?float $maxTime = null): Reservation
+    {
+        throw new ReserveNotSupportedException(__CLASS__);
+    }
+
     /**
      * {@inheritdoc}
      */

diff --git a/src/Symfony/Component/RateLimiter/Tests/CompoundLimiterTest.php b/src/Symfony/Component/RateLimiter/Tests/CompoundLimiterTest.php
@@ -14,6 +14,7 @@
 use PHPUnit\Framework\TestCase;
 use Symfony\Bridge\PhpUnit\ClockMock;
 use Symfony\Component\RateLimiter\CompoundLimiter;
+use Symfony\Component\RateLimiter\Exception\ReserveNotSupportedException;
 use Symfony\Component\RateLimiter\FixedWindowLimiter;
 use Symfony\Component\RateLimiter\Storage\InMemoryStorage;
 
@@ -38,22 +39,26 @@ public function testConsume()
         $limiter3 = $this->createLimiter(12, new \DateInterval('PT30S'));
         $limiter = new CompoundLimiter([$limiter1, $limiter2, $limiter3]);
 
-        // Reach limiter 1 limit, verify that limiter2 available tokens reduced by 5 and fetch successfully limiter 1
-        $this->assertEquals(3, $limiter->consume(5)->getRemainingTokens(), 'Limiter 1 reached the limit');
+        $this->assertEquals(0, $limiter->consume(4)->getRemainingTokens(), 'Limiter 1 reached the limit');
         sleep(1); // reset limiter1's window
-        $this->assertTrue($limiter->consume(2)->isAccepted());
+        $this->assertTrue($limiter->consume(3)->isAccepted());
 
-        // Reach limiter 2 limit, verify that limiter2 available tokens reduced by 5 and and fetch successfully
         $this->assertEquals(0, $limiter->consume()->getRemainingTokens(), 'Limiter 2 has no remaining tokens left');
-        sleep(9); // reset limiter2's window
+        sleep(10); // reset limiter2's window
         $this->assertTrue($limiter->consume(3)->isAccepted());
 
-        // Reach limiter 3 limit, verify that limiter2 available tokens reduced by 5 and fetch successfully
         $this->assertEquals(0, $limiter->consume()->getRemainingTokens(), 'Limiter 3 reached the limit');
         sleep(20); // reset limiter3's window
         $this->assertTrue($limiter->consume()->isAccepted());
     }
 
+    public function testReserve()
+    {
+        $this->expectException(ReserveNotSupportedException::class);
+
+        (new CompoundLimiter([$this->createLimiter(4, new \DateInterval('PT1S'))]))->reserve();
+    }
+
     private function createLimiter(int $limit, \DateInterval $interval): FixedWindowLimiter
     {
         return new FixedWindowLimiter('test'.$limit, $limit, $interval, $this->storage);

diff --git a/src/Symfony/Component/RateLimiter/Tests/FixedWindowLimiterTest.php b/src/Symfony/Component/RateLimiter/Tests/FixedWindowLimiterTest.php
@@ -60,7 +60,7 @@ public function testConsumeOutsideInterval()
         sleep(10);
         $limit = $limiter->consume(10);
         $this->assertEquals(0, $limit->getRemainingTokens());
-        $this->assertEquals(time() + 60, $limit->getRetryAfter()->getTimestamp());
+        $this->assertTrue($limit->isAccepted());
     }
 
     public function testWrongWindowFromCache()