Merge pull request #100 from e-zannelli/feat-guzzle-failure-detector

Add guzzle failure detector

Author: ackintosh

README.md

@@ -418,6 +418,35 @@ $middleware = new GuzzleMiddleware(
 );
 ```
 
+### How does Guzzle Middleware determine the failure?
+
+By default, if the next handler promise is fulfilled ganesha will consider it a success, and a failure if it is rejected.
+
+You can implement your own rules on fulfilled response by passing an implementation of `FailureDetectorInterface` to the middleware.
+
+```php
+use Ackintosh\Ganesha\GuzzleMiddleware\FailureDetectorInterface;
+use Psr\Http\Message\ResponseInterface;
+
+class HttpStatusFailureDetector implements FailureDetectorInterface
+{
+    public function isFailureResponse(ResponseInterface $response) : bool
+    {
+        return in_array($response->getStatusCode(), [503, 504], true);
+    }
+}
+
+// ---
+$ganesha = Builder::withRateStrategy()
+    // ...
+    ->build();
+$middleware = new GuzzleMiddleware(
+    $ganesha,
+    // Pass the failure detector to the GuzzleMiddleware constructor.
+    failureDetector: new HttpStatusFailureDetector()
+);
+```
+
 ## [Ganesha :heart: OpenAPI Generator](#table-of-contents)
 
 PHP client generated by [OpenAPI Generator](https://github.com/OpenAPITools/openapi-generator) is using Guzzle as HTTP client and as we mentioned as [Ganesha :heart: Guzzle](https://github.com/ackintosh/ganesha#ganesha-heart-guzzle), Guzzle Middleware powered by Ganesha is ready. So it is easily possible to integrate Ganesha and the PHP client generated by OpenAPI Generator in a smart way as below.

src/Ganesha/GuzzleMiddleware.php

@@ -3,6 +3,8 @@
 
 use Ackintosh\Ganesha;
 use Ackintosh\Ganesha\Exception\RejectedException;
+use Ackintosh\Ganesha\GuzzleMiddleware\AlwaysSuccessFailureDetector;
+use Ackintosh\Ganesha\GuzzleMiddleware\FailureDetectorInterface;
 use Ackintosh\Ganesha\GuzzleMiddleware\ServiceNameExtractor;
 use Ackintosh\Ganesha\GuzzleMiddleware\ServiceNameExtractorInterface;
 use Psr\Http\Message\RequestInterface;
@@ -19,12 +21,19 @@ class GuzzleMiddleware
      */
     private $serviceNameExtractor;
 
+    /**
+     * @var FailureDetectorInterface
+     */
+    private $failureDetector;
+
     public function __construct(
         Ganesha $ganesha,
-        ServiceNameExtractorInterface $serviceNameExtractor = null
+        ServiceNameExtractorInterface $serviceNameExtractor = null,
+        FailureDetectorInterface $failureDetector = null
     ) {
         $this->ganesha = $ganesha;
         $this->serviceNameExtractor = $serviceNameExtractor ?: new ServiceNameExtractor();
+        $this->failureDetector = $failureDetector ?: new AlwaysSuccessFailureDetector();
     }
 
     /**
@@ -48,7 +57,11 @@ public function __invoke(callable $handler): \Closure
 
             return $promise->then(
                 function ($value) use ($serviceName) {
-                    $this->ganesha->success($serviceName);
+                    if ($this->failureDetector->isFailureResponse($value)) {
+                        $this->ganesha->failure($serviceName);
+                    } else {
+                        $this->ganesha->success($serviceName);
+                    }
                     return \GuzzleHttp\Promise\promise_for($value);
                 },
                 function ($reason) use ($serviceName) {

src/Ganesha/GuzzleMiddleware/AlwaysSuccessFailureDetector.php

@@ -0,0 +1,13 @@
+<?php
+
+namespace Ackintosh\Ganesha\GuzzleMiddleware;
+
+use Psr\Http\Message\ResponseInterface;
+
+class AlwaysSuccessFailureDetector implements FailureDetectorInterface
+{
+    public function isFailureResponse(ResponseInterface $response): bool
+    {
+        return false;
+    }
+}

src/Ganesha/GuzzleMiddleware/FailureDetectorInterface.php

@@ -0,0 +1,10 @@
+<?php
+
+namespace Ackintosh\Ganesha\GuzzleMiddleware;
+
+use Psr\Http\Message\ResponseInterface;
+
+interface FailureDetectorInterface
+{
+    public function isFailureResponse(ResponseInterface $response): bool;
+}

tests/Ackintosh/Ganesha/GuzzleMiddlewareTest.php

@@ -2,6 +2,7 @@
 namespace Ackintosh\Ganesha;
 
 use Ackintosh\Ganesha\Exception\RejectedException;
+use Ackintosh\Ganesha\GuzzleMiddleware\FailureDetectorInterface;
 use Ackintosh\Ganesha\Storage\Adapter\Memcached;
 use Ackintosh\Ganesha\Storage\Adapter\Redis;
 use GuzzleHttp\Client;
@@ -94,6 +95,28 @@ public function recordsSuccessOn500()
         );
     }
 
+    /**
+     * @test
+     * @vcr guzzle_responses.yml
+     */
+    public function failureDetectorControlsIfResponseIsFailure()
+    {
+        $failureDetector = $this->createMock(FailureDetectorInterface::class);
+        $failureDetector->expects($this->once())->method('isFailureResponse')->willReturn(true);
+        $client = $this->buildClient($failureDetector);
+        $response = $client->get('http://api.example.com/awesome_resource/200');
+
+        $this->assertSame(200, $response->getStatusCode());
+        $this->assertSame(
+            1,
+            $this->adapter->load(Storage\StorageKeys::KEY_PREFIX . 'api.example.com' . Storage\StorageKeys::KEY_SUFFIX_FAILURE)
+        );
+        $this->assertSame(
+            0,
+            $this->adapter->load(Storage\StorageKeys::KEY_PREFIX . 'api.example.com' . Storage\StorageKeys::KEY_SUFFIX_SUCCESS)
+        );
+    }
+
     /**
      * @test
      */
@@ -162,7 +185,7 @@ public function reject()
     /**
      * @return Client
      */
-    private function buildClient()
+    private function buildClient(?FailureDetectorInterface $failureDetector = null)
     {
         $ganesha = Builder::withRateStrategy()
             ->timeWindow(30)
@@ -172,7 +195,8 @@ private function buildClient()
             ->adapter($this->adapter)
             ->build();
 
-        $middleware = new GuzzleMiddleware($ganesha);
+
+        $middleware = new GuzzleMiddleware($ganesha, null, $failureDetector);
         $handlers = HandlerStack::create();
         $handlers->push($middleware);