feat: add retryable

src/Middleware/RetryMiddleware.php

@@ -0,0 +1,97 @@
+<?php
+/*
+ * Copyright 2021 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+namespace Google\Auth\Middleware;
+
+use Psr\Http\Message\RequestInterface;
+use Psr\Http\Message\ResponseInterface;
+
+/**
+ * RetryMiddleware is a Guzzle Middleware that allows for retrying certain error
+ * codes automatically.
+ *
+ * Requests are accessed using the Simple API access developer key.
+ */
+class RetryMiddleware
+{
+    private $retryAttempts;
+
+    /**
+     * Creates a new RetryMiddleware.
+     *
+     * @param array $config {
+     *     Configuration array
+     *
+     *     @type int $retryAttempts number of retry attempts.
+     * }
+     */
+    public function __construct(array $config = [])
+    {
+        if (!isset($config['retryAttempts'])) {
+            throw new \InvalidArgumentException('requires retryAttempts to be set');
+        }
+
+        $this->retryAttempts = $config['retryAttempts'];
+    }
+
+    /**
+     * Retry the response if it has retryable error codes.
+     *
+     *   use Google\Auth\Middleware\AuthTokenMiddleware;
+     *   use Google\Auth\Middleware\RetryMiddleware;
+     *   use Google\Auth\OAuth2;
+     *   use GuzzleHttp\Client;
+     *   use GuzzleHttp\HandlerStack;
+     *
+     *   $config = [..<oauth config param>.];
+     *   $oauth2 = new OAuth2($config)
+     *   $authMiddleware = new AuthTokenMiddleware($oauth2);
+     *   $retryMiddleware = new RetryMiddleware(['retryAttempts' => 3]);
+     *   $stack = HandlerStack::create();
+     *   $stack->push($authMiddleware);
+     *   $stack->push($retryMiddleware);
+     *
+     *   $client = new Client([
+     *       'handler' => $stack,
+     *       'base_uri' => 'https://www.googleapis.com/taskqueue/v1beta2/projects/',
+     *       'auth' => 'google_auth' // authorize all requests
+     *   ]);
+     *
+     *   $res = $client->get('myproject/taskqueues/myqueue');
+     *
+     * @param callable $handler
+     * @return \Closure
+     */
+    public function __invoke(callable $handler)
+    {
+        return function (RequestInterface $request, array $options) use ($handler) {
+            $response = $handler($request, $options);
+            for ($attempts = 0; $attempts < $this->retryAttempts; $attempts++) {
+                if ($this->isRetryable($response)) {
+                    $response = $handler($request, $options);
+                }
+            }
+            return $response;
+        };
+    }
+
+    private function isRetryable(ResponseInterface $response)
+    {
+        // no-op for now, this is a Proof of Concept!
+        return false;
+    }
+}