Add retry logic (#41)

Makefile

@@ -9,15 +9,15 @@ composer:
 	@$(RUNNER) "composer $(filter-out $@,$(MAKECMDGOALS))"
 dependencies:
 	make -s composer update -- --prefer-dist
-test: dependencies
+test:
 	$(RUNNER) "phpunit --coverage-text --coverage-html ./coverage "
-php: dependencies
+php:
 	$(RUNNER) "php $(filter-out $@,$(MAKECMDGOALS))"
-cs: dependencies
+cs:
 	$(RUNNER) "./vendor/bin/phpcs --standard=PSR2 src/"
-cbf: dependencies
+cbf:
 	$(RUNNER) "./vendor/bin/phpcbf --standard=PSR2 src/"
-doc: dependencies
+doc:
 	$(RUNNER) "./vendor/bin/phpdoc"
 	$(RUNNER) "./vendor/bin/phpdocmd docs/structure.xml docs --index README.md"
 %:

README.md

@@ -595,6 +595,21 @@ customers = $ChartMogul\Customer::all([
 
 Learn more about this virtual package at [here](http://docs.php-http.org/en/latest/httplug/users.html).
 
+
+### Rate Limits & Exponential Backoff
+
+The library will keep retrying if the request exceeds the rate limit or if there's any network related error.
+By default, the request will be retried for 20 times (approximated 15 minutes) before finally giving up.
+
+You can change the retry count using `Configuration` object:
+
+```php
+ChartMogul\Configuration::getDefaultConfiguration()
+    ->setAccountToken('<YOUR_ACCOUNT_TOKEN>')
+    ->setSecretKey('<YOUR_SECRET_KEY>')
+    ->setRetries(15); //0 disables retrying
+```
+
 ## API Documentation
 
 Find the full public API documentation [here](docs/README.md).

composer.json

@@ -23,7 +23,9 @@
         "php-http/client-implementation": "^1.0",
         "zendframework/zend-diactoros": "^1.3",
         "php-http/guzzle6-adapter": "^1.0",
-        "doctrine/collections": "^1.3"
+        "doctrine/collections": "^1.3",
+        "stechstudio/backoff": "^1.0"
+
     },
     "require-dev": {
         "php-http/mock-client": "^0.3",

src/Configuration.php

@@ -3,6 +3,8 @@
 
 namespace ChartMogul;
 
+const DEFAULT_MAX_RETRIES = 20;
+
 /**
  *
  * @codeCoverageIgnore
@@ -23,16 +25,22 @@ class Configuration
      * @var string
      */
     private $secretKey = '';
+    /**
+     * @var int
+     * maximum retry attempts
+     */
+    private $retry = DEFAULT_MAX_RETRIES;
 
     /**
      * Creates new config object from accountToken and secretKey
      * @param string $accountToken
      * @param string $secretKey
      */
-    public function __construct($accountToken = '', $secretKey = '')
+    public function __construct($accountToken = '', $secretKey = '', $retries = DEFAULT_MAX_RETRIES)
     {
         $this->accountToken = $accountToken;
         $this->secretKey = $secretKey;
+        $this->retries = $retries;
     }
 
     /**
@@ -75,6 +83,26 @@ public function setSecretKey($secretKey)
         return $this;
     }
 
+    /**
+     * Get retries
+     * @return int
+     */
+    public function getRetries()
+    {
+        return $this->retries;
+    }
+
+    /**
+     * Set max retries
+     * @param int $retries
+     * @return self
+     */
+    public function setRetries($retries)
+    {
+        $this->retries = $retries;
+        return $this;
+    }
+
     /**
      * Set Default Config object. Default config object is used when no config object is passed during resource call
      * @return  Configuration

src/Http/Client.php

@@ -147,6 +147,15 @@ public function getBasicAuthHeader()
         );
     }
 
+    protected function sendWithRetry(Request $request)
+    {
+        $backoff = new Retry($this->config->getRetries());
+        $response =  $backoff->retry(function () use ($request) {
+            return $this->client->sendRequest($request);
+        });
+        return $this->handleResponse($response);
+    }
+
     public function send($path = '', $method = 'GET', $data = [])
     {
 
@@ -171,9 +180,7 @@ public function send($path = '', $method = 'GET', $data = [])
             $request->getBody()->write(json_encode($data));
         }
 
-        $response = $this->client->sendRequest($request);
-
-        return $this->handleResponse($response);
+        return $this->sendWithRetry($request);
     }
 
     /**

src/Http/Retry.php

@@ -0,0 +1,56 @@
+<?php
+namespace ChartMogul\Http;
+
+use Psr\Http\Message\ResponseInterface;
+use STS\Backoff\Backoff;
+
+class ExponentialStrategy extends \STS\Backoff\Strategies\ExponentialStrategy
+{
+    // min wait time
+    protected $base = 1000;
+}
+
+class Retry
+{
+
+    private $retries;
+
+    public function __construct($retries)
+    {
+        $this->retries = $retries;
+    }
+
+    private function retryHTTPStatus($status)
+    {
+        return $status == 429 || ($status >= 500 && $status < 600);
+    }
+
+    protected function shouldRetry($attempt, $maxAttempts, ResponseInterface $response = null, \Exception $ex = null)
+    {
+        if ($attempt >= $maxAttempts && ! is_null($ex)) {
+            throw  $ex;
+        }
+
+        if (!is_null($response)) {
+            return $attempt < $maxAttempts && $this->retryHTTPStatus($response->getStatusCode());
+        }
+
+        // retry on all network related errors
+        return $attempt < $maxAttempts && $ex instanceof \Http\Client\Exception\NetworkException;
+    }
+
+    public function retry($callback)
+    {
+        if ($this->retries === 0) {
+            return $callback();
+        }
+        $backoff = new Backoff($this->retries, new ExponentialStrategy(), 60*1000, true);
+        $backoff->setDecider($this);
+        return $backoff->run($callback);
+    }
+
+    public function __invoke($attempt, $maxAttempts, $response, $exception)
+    {
+        return $this->shouldRetry($attempt, $maxAttempts, $response, $exception);
+    }
+}

tests/Unit/Http/ClientTest.php

@@ -2,6 +2,9 @@
 
 use ChartMogul\Http\Client;
 use ChartMogul\Exceptions\ChartMogulException;
+use GuzzleHttp\Psr7;
+use GuzzleHttp\Psr7\Response;
+use Zend\Diactoros\Request;
 
 class ClientTest extends \PHPUnit\Framework\TestCase
 {
@@ -102,6 +105,35 @@ public function testHandleResponseExceptions($status, $exception)
     }
 
 
+    private function getMockClient($retries, $statuses, $exceptions = []){
+        $mock = $this->getMockBuilder(Client::class)
+            ->disableOriginalConstructor()
+            ->setMethods(['getBasicAuthHeader', 'getUserAgent'])
+            ->getMock();
+
+        $mock->expects($this->once())
+            ->method('getBasicAuthHeader')
+            ->willReturn('auth');
+
+        $mock->expects($this->once())
+            ->method('getUserAgent')
+            ->willReturn('agent');
+
+
+        $mockClient = new \Http\Mock\Client();
+        $mock->setHttpClient($mockClient);
+        $mock->setConfiguration(\ChartMogul\Configuration::getDefaultConfiguration()->setRetries($retries));
+        $stream = Psr7\stream_for('{}');
+        foreach($statuses as $status) {
+            $response = new Response($status, ['Content-Type' => 'application/json'], $stream);
+            $mockClient->addResponse($response);
+        }
+        foreach($exceptions as $exception) {
+            $mockClient->addException($exception);
+        }
+        return [$mock, $mockClient];
+    }
+
     public function providerSend()
     {
         return [
@@ -123,33 +155,11 @@ public function providerSend()
      */
     public function testSend($path, $method, $data, $target, $rBody)
     {
-        $mock = $this->getMockBuilder(Client::class)
-            ->disableOriginalConstructor()
-            ->setMethods(['getBasicAuthHeader', 'getUserAgent', 'handleResponse'])
-            ->getMock();
-
-        $mock->expects($this->once())
-            ->method('getBasicAuthHeader')
-            ->willReturn('auth');
-
-        $mock->expects($this->once())
-            ->method('getUserAgent')
-            ->willReturn('agent');
-
-        $response = $this->getMockBuilder('Psr\Http\Message\ResponseInterface')->getMock();
-
-        $mock->expects($this->once())
-            ->method('handleResponse')
-            ->willReturn($response);
-
-        $mockClient = new \Http\Mock\Client();
-        $mock->setHttpClient($mockClient);
-        $mockClient->addResponse($response);
-
+        list($mock, $mockClient) = $this->getMockClient(20, [200]);
 
         $returnedResponse = $mock->send($path, $method, $data);
         $request= $mockClient->getRequests()[0];
-        $this->assertSame($response, $returnedResponse);
+        $this->assertSame($returnedResponse, []);
         $this->assertEquals($request->getHeader('user-agent'), ['agent']);
         $this->assertEquals($request->getHeader('Authorization'), ['auth']);
         $this->assertEquals($request->getHeader('content-type'), ['application/json']);
@@ -158,4 +168,46 @@ public function testSend($path, $method, $data, $target, $rBody)
         $request->getBody()->rewind();
         $this->assertEquals($request->getBody()->getContents(), $rBody);
     }
+
+    /**
+    * @expectedException     ChartMogul\Exceptions\ChartMogulException
+    */
+    public function testNoRetry()
+    {
+        list($mock, $mockClient) = $this->getMockClient(0, [500]);
+
+        $returnedResponse = $mock->send('', 'GET', []);
+        $this->assertEquals(count($mockClient->getRequests()), 1);
+    }
+
+    public function testRetryHTTP()
+    {
+        list($mock, $mockClient) = $this->getMockClient(10, [500, 429, 200]);
+
+        $returnedResponse = $mock->send('', 'GET', []);
+        $this->assertEquals(count($mockClient->getRequests()), 3);
+    }
+    public function testRetryNetworkError()
+    {
+        list($mock, $mockClient) = $this->getMockClient(10, [200], [
+            new \Http\Client\Exception\NetworkException("some error", new Request()),
+        ]);
+
+        $returnedResponse = $mock->send('', 'GET', []);
+        $this->assertEquals(count($mockClient->getRequests()), 2);
+    }
+    /**
+    * @expectedException     \Http\Client\Exception\NetworkException
+    */
+    public function testRetryMaxAttemptReached()
+    {
+        list($mock, $mockClient) = $this->getMockClient(1, [200], [
+            new \Http\Client\Exception\NetworkException("some error", new Request()),
+            new \Http\Client\Exception\NetworkException("some error", new Request()),
+        ]);
+
+
+        $returnedResponse = $mock->send('', 'GET', []);
+        $this->assertEquals(count($mockClient->getRequests()), 1);
+    }
 }