Adds InMemoryThrottler for mocking throttler functionality.

Provides interface for throttler.
mariusbalcytis · Jun 17, 2017 · 1feace8 · 1feace8
1 parent db69219
commit 1feace8
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Showing 10 changed files with 199 additions and 11 deletions.
diff --git a/README.md b/README.md
@@ -118,7 +118,7 @@ Some of reviewed alternatives:
 
 ## Semantic versioning
 
-This bundle follows [semantic versioning](http://semver.org/spec/v2.0.0.html).
+This library follows [semantic versioning](http://semver.org/spec/v2.0.0.html).
 
 See [Symfony BC rules](http://symfony.com/doc/current/contributing/code/bc.html) for basic
 information about what can be changed and what not in the API.
@@ -132,6 +132,7 @@ so that behaviour on high traffic could be tested. So, generally,
 it's easier to run them in docker.
 
 ```
+composer update
 cd docker
 docker-compose up -d
 docker exec -it gentle_force_test_php vendor/bin/phpunit

diff --git a/composer.json b/composer.json
@@ -9,7 +9,7 @@
     },
     "require-dev": {
         "friendsofphp/php-cs-fixer": "^2.2",
-        "phpunit/phpunit": "^4.8",
+        "phpunit/phpunit": "^4.8.35",
         "misterion/ko-process": "^0.5.3",
         "symfony/stopwatch": "^3.2"
     },

diff --git a/src/InMemory/InMemoryThrottler.php b/src/InMemory/InMemoryThrottler.php
@@ -0,0 +1,113 @@
+<?php
+
+namespace Maba\GentleForce\InMemory;
+
+use Maba\GentleForce\Exception\RateLimitReachedException;
+use Maba\GentleForce\IncreaseResult;
+use Maba\GentleForce\RateLimitProvider;
+use Maba\GentleForce\ThrottlerInterface;
+
+/**
+ * Only for testing purposes (mocking) - mimics functionality without external dependencies.
+ * Current time is also mockable.
+ *
+ * This allows writing consistent and fast tests for functionality that uses throttler.
+ *
+ * @internal
+ */
+class InMemoryThrottler implements ThrottlerInterface
+{
+    private $rateLimitProvider;
+    private $microtimeProvider;
+
+    /**
+     * @var array
+     */
+    private $storage = [];
+
+    public function __construct(RateLimitProvider $rateLimitProvider, MicrotimeProvider $microtimeProvider)
+    {
+        $this->rateLimitProvider = $rateLimitProvider;
+        $this->microtimeProvider = $microtimeProvider;
+    }
+
+    /**
+     * @param string $useCaseKey configured key for this use case, like "credentials_error_ip"
+     * @param string $identifier rate-limiting group, like IP address or username
+     * @return IncreaseResult
+     * @throws RateLimitReachedException
+     */
+    public function checkAndIncrease($useCaseKey, $identifier)
+    {
+        $now = $this->microtimeProvider->getMicrotime();
+        $rateLimits = $this->rateLimitProvider->getRateLimits($useCaseKey);
+        $key = $this->buildKey($useCaseKey, $identifier);
+
+        $totals = [];
+        $usagesAvailable = [];
+        $validAfter = 0;
+        foreach ($rateLimits as $rateLimit) {
+            $tokensPerUsage = $rateLimit->calculateTokensPerUsage();
+            $bucketSize = $rateLimit->calculateBucketSize();
+            $subKey = $tokensPerUsage . ':' . $bucketSize;
+            $total = 0;
+            $emptyAt = isset($this->storage[$key][$subKey]) ? $this->storage[$key][$subKey] : null;
+            if ($emptyAt !== null) {
+                $total = max(0, $emptyAt - $now);
+            }
+            $total += $tokensPerUsage;
+            if ($total > $bucketSize) {
+                $validAfter = max($validAfter, $total - $bucketSize);
+            }
+
+            $totals[$subKey] = $total;
+            $usagesAvailable[$subKey] = $total / $tokensPerUsage;
+        }
+
+        if ($validAfter > 0) {
+            throw new RateLimitReachedException($validAfter);
+        }
+
+        $maxUsagesAvailable = 0;
+        foreach ($totals as $subKey => $total) {
+            $this->storage[$key][$subKey] = $now + $total;
+            $maxUsagesAvailable = max($maxUsagesAvailable, $usagesAvailable[$subKey]);
+        }
+
+        return new IncreaseResult($this, floor($maxUsagesAvailable), $useCaseKey, $identifier);
+    }
+
+    /**
+     * @param string $useCaseKey configured key for this use case, like "credentials_error_ip"
+     * @param string $identifier rate-limiting group, like IP address or username
+     */
+    public function decrease($useCaseKey, $identifier)
+    {
+        $rateLimits = $this->rateLimitProvider->getRateLimits($useCaseKey);
+        $key = $this->buildKey($useCaseKey, $identifier);
+
+        foreach ($rateLimits as $rateLimit) {
+            $tokensPerUsage = $rateLimit->calculateTokensPerUsage();
+            $bucketSize = $rateLimit->calculateBucketSize();
+            $subKey = $tokensPerUsage . ':' . $bucketSize;
+            if (isset($this->storage[$key][$subKey])) {
+                $this->storage[$key][$subKey] -= $tokensPerUsage;
+            }
+        }
+    }
+
+    /**
+     * @param string $useCaseKey configured key for this use case, like "credentials_error_ip"
+     * @param string $identifier rate-limiting group, like IP address or username
+     */
+    public function reset($useCaseKey, $identifier)
+    {
+        $key = $this->buildKey($useCaseKey, $identifier);
+        unset($this->storage[$key]);
+    }
+
+    private function buildKey($useCaseKey, $identifier)
+    {
+        return $useCaseKey . ':' . $identifier;
+    }
+}
diff --git a/src/InMemory/MicrotimeProvider.php b/src/InMemory/MicrotimeProvider.php
@@ -0,0 +1,24 @@
+<?php
+
+namespace Maba\GentleForce\InMemory;
+
+class MicrotimeProvider
+{
+    /**
+     * @var float
+     */
+    private $mockedMicrotime;
+
+    /**
+     * @param float $mockedMicrotime
+     */
+    public function setMockedMicrotime($mockedMicrotime)
+    {
+        $this->mockedMicrotime = $mockedMicrotime;
+    }
+
+    public function getMicrotime()
+    {
+        return $this->mockedMicrotime !== null ? $this->mockedMicrotime : microtime(true);
+    }
+}
diff --git a/src/IncreaseResult.php b/src/IncreaseResult.php
@@ -9,7 +9,7 @@ class IncreaseResult
     private $useCaseKey;
     private $identifier;
 
-    public function __construct(Throttler $throttler, $usagesAvailable, $useCaseKey, $identifier)
+    public function __construct(ThrottlerInterface $throttler, $usagesAvailable, $useCaseKey, $identifier)
     {
         $this->throttler = $throttler;
         $this->usagesAvailable = $usagesAvailable;

diff --git a/src/Throttler.php b/src/Throttler.php
@@ -8,7 +8,7 @@
 use Maba\GentleForce\Redis\Result\CheckAndIncreaseResult;
 use Predis\Client;
 
-class Throttler
+class Throttler implements ThrottlerInterface
 {
     private $client;
     private $rateLimitProvider;

diff --git a/src/ThrottlerInterface.php b/src/ThrottlerInterface.php
@@ -0,0 +1,28 @@
+<?php
+
+namespace Maba\GentleForce;
+
+use Maba\GentleForce\Exception\RateLimitReachedException;
+
+interface ThrottlerInterface
+{
+    /**
+     * @param string $useCaseKey configured key for this use case, like "credentials_error_ip"
+     * @param string $identifier rate-limiting group, like IP address or username
+     * @return IncreaseResult
+     * @throws RateLimitReachedException
+     */
+    public function checkAndIncrease($useCaseKey, $identifier);
+
+    /**
+     * @param string $useCaseKey configured key for this use case, like "credentials_error_ip"
+     * @param string $identifier rate-limiting group, like IP address or username
+     */
+    public function decrease($useCaseKey, $identifier);
+
+    /**
+     * @param string $useCaseKey configured key for this use case, like "credentials_error_ip"
+     * @param string $identifier rate-limiting group, like IP address or username
+     */
+    public function reset($useCaseKey, $identifier);
+}
diff --git a/tests/Functional/FunctionalInMemoryThrottlerTest.php b/tests/Functional/FunctionalInMemoryThrottlerTest.php
@@ -0,0 +1,16 @@
+<?php
+
+namespace Maba\GentleForce\Tests\Functional;
+
+use Maba\GentleForce\InMemory\InMemoryThrottler;
+use Maba\GentleForce\InMemory\MicrotimeProvider;
+use Maba\GentleForce\RateLimitProvider;
+
+class FunctionalInMemoryThrottlerTest extends FunctionalTest
+{
+
+    protected function createThrottler(RateLimitProvider $rateLimitProvider)
+    {
+        return new InMemoryThrottler($rateLimitProvider, new MicrotimeProvider());
+    }
+}
diff --git a/tests/Functional/FunctionalTest.php b/tests/Functional/FunctionalTest.php
@@ -6,6 +6,7 @@
 use Maba\GentleForce\RateLimit\UsageRateLimit;
 use Maba\GentleForce\RateLimitProvider;
 use Maba\GentleForce\Throttler;
+use Maba\GentleForce\ThrottlerInterface;
 use PHPUnit_Framework_TestCase as TestCase;
 use Predis\Client;
 use Symfony\Component\Stopwatch\Stopwatch;
@@ -19,7 +20,7 @@ class FunctionalTest extends TestCase
     const ERROR_CORRECTION_PERIOD_MS = 60;
 
     /**
-     * @var Throttler
+     * @var ThrottlerInterface
      */
     private $throttler;
 
@@ -118,18 +119,22 @@ public function testWithReset()
 
     private function setUpThrottler($rateLimits)
     {
-        $prefix = 'functional_test_' . microtime();
-
         $rateLimitProvider = new RateLimitProvider();
         $rateLimitProvider->registerRateLimits(self::USE_CASE_KEY, $rateLimits);
 
-        $this->throttler = new Throttler(new Client([
-            'host' => isset($_ENV['REDIS_HOST']) ? $_ENV['REDIS_HOST'] : 'localhost',
-        ]), $rateLimitProvider, $prefix);
+        $this->throttler = $this->createThrottler($rateLimitProvider);
 
         $this->event = (new Stopwatch())->start('');
     }
 
+    protected function createThrottler(RateLimitProvider $rateLimitProvider)
+    {
+        $prefix = 'functional_test_' . microtime();
+        return new Throttler(new Client([
+            'host' => isset($_ENV['REDIS_HOST']) ? $_ENV['REDIS_HOST'] : 'localhost',
+        ]), $rateLimitProvider, $prefix);
+    }
+
     private function assertUsagesValid($countOfUsages)
     {
         for ($i = 0; $i < $countOfUsages; $i++) {

diff --git a/tests/Functional/RaceConditionsTest.php b/tests/Functional/RaceConditionsTest.php
@@ -8,6 +8,7 @@
 use Maba\GentleForce\RateLimit\UsageRateLimit;
 use Maba\GentleForce\RateLimitProvider;
 use Maba\GentleForce\Throttler;
+use Maba\GentleForce\ThrottlerInterface;
 use PHPUnit_Framework_TestCase as TestCase;
 use Predis\Client;
 use Symfony\Component\Stopwatch\Stopwatch;
@@ -19,7 +20,7 @@ class RaceConditionsTest extends TestCase
     const ID = 'user1';
 
     /**
-     * @var Throttler
+     * @var ThrottlerInterface
      */
     private $throttler;