feat: add StdOutLogger and LoggingTrait

composer.json

@@ -14,7 +14,8 @@
     "guzzlehttp/guzzle": "^7.4.5",
     "guzzlehttp/psr7": "^2.4.5",
     "psr/http-message": "^1.1||^2.0",
-    "psr/cache": "^2.0||^3.0"
+    "psr/cache": "^2.0||^3.0",
+    "psr/log": "^3.0"
   },
   "require-dev": {
     "guzzlehttp/promises": "^2.0",

src/ApplicationDefaultCredentials.php

@@ -23,12 +23,15 @@
 use Google\Auth\Credentials\ServiceAccountCredentials;
 use Google\Auth\HttpHandler\HttpClientCache;
 use Google\Auth\HttpHandler\HttpHandlerFactory;
+use Google\Auth\Logging\StdOutLogger;
 use Google\Auth\Middleware\AuthTokenMiddleware;
 use Google\Auth\Middleware\ProxyAuthTokenMiddleware;
 use Google\Auth\Subscriber\AuthTokenSubscriber;
 use GuzzleHttp\Client;
 use InvalidArgumentException;
+use PHPUnit\TextUI\XmlConfiguration\Logging\Logging;
 use Psr\Cache\CacheItemPoolInterface;
+use Psr\Log\LoggerInterface;
 
 /**
  * ApplicationDefaultCredentials obtains the default credentials for
@@ -69,6 +72,8 @@
  */
 class ApplicationDefaultCredentials
 {
+    private const SDK_DEBUG_FLAG = 'GOOGLE_SDK_DEBUG_LOGGING';
+
     /**
      * @deprecated
      *
@@ -145,7 +150,8 @@ public static function getMiddleware(
      *   user-defined scopes exist, expressed either as an Array or as a
      *   space-delimited string.
      * @param string $universeDomain Specifies a universe domain to use for the
-     *   calling client library
+     *   calling client library.
+     * @param null|false|LoggerInterface $logger A PSR3 compliant LoggerInterface.
      *
      * @return FetchAuthTokenInterface
      * @throws DomainException if no implementation can be obtained.
@@ -157,7 +163,8 @@ public static function getCredentials(
         CacheItemPoolInterface $cache = null,
         $quotaProject = null,
         $defaultScope = null,
-        string $universeDomain = null
+        string $universeDomain = null,
+        null|false|LoggerInterface $logger = null,
     ) {
         $creds = null;
         $jsonKey = CredentialsLoader::fromEnv()
@@ -170,7 +177,7 @@ public static function getCredentials(
                 HttpClientCache::setHttpClient($client);
             }
 
-            $httpHandler = HttpHandlerFactory::build($client);
+            $httpHandler = HttpHandlerFactory::build($client, $logger);
         }
 
         if (is_null($quotaProject)) {
@@ -321,6 +328,40 @@ public static function getIdTokenCredentials(
         return $creds;
     }
 
+    /**
+     * Returns a StdOutLogger instance
+     *
+     * @return null|LoggerInterface
+     */
+    public static function getDefaultLogger(): null|LoggerInterface
+    {
+        $loggingFlag = getenv(self::SDK_DEBUG_FLAG);
+
+        // Env var is not set
+        if (!is_string($loggingFlag)) {
+            if (is_array($loggingFlag)) {
+                trigger_error('The ' . self::SDK_DEBUG_FLAG . ' is set, but it is set to another value than false, true, 0 or 1. Logging is disabled');
+                return null;
+            }
+
+            return null;
+        }
+
+        $loggingFlag = strtolower($loggingFlag);
+
+        // Env Var is not true
+        if ($loggingFlag !== 'true' && $loggingFlag !== '1') {
+            // Env var is set to a non valid value
+            if ($loggingFlag !== 'false' && $loggingFlag !== '0') {
+                trigger_error('The ' . self::SDK_DEBUG_FLAG . ' is set, but it is set to another value than false, true, 0 or 1. Logging is disabled');
+            }
+
+            return null;
+        }
+
+        return new StdOutLogger();
+    }
+
     /**
      * @return string
      */

src/HttpHandler/Guzzle6HttpHandler.php

@@ -16,23 +16,35 @@
  */
 namespace Google\Auth\HttpHandler;
 
+use Google\Auth\Logging\LogEvent;
+use Google\Auth\Logging\LoggingTrait;
 use GuzzleHttp\ClientInterface;
 use Psr\Http\Message\RequestInterface;
 use Psr\Http\Message\ResponseInterface;
+use Psr\Log\LoggerInterface;
 
 class Guzzle6HttpHandler
 {
+    use LoggingTrait;
+
     /**
      * @var ClientInterface
      */
     private $client;
 
+    /**
+     * @var null|LoggerInterface
+     */
+    private $logger;
+
     /**
      * @param ClientInterface $client
+     * @param null|LoggerInterface $logger
      */
-    public function __construct(ClientInterface $client)
+    public function __construct(ClientInterface $client, LoggerInterface $logger = null)
     {
         $this->client = $client;
+        $this->logger = $logger;
     }
 
     /**
@@ -44,7 +56,38 @@ public function __construct(ClientInterface $client)
      */
     public function __invoke(RequestInterface $request, array $options = [])
     {
-        return $this->client->send($request, $options);
+        $requestEvent = null;
+
+        if ($this->logger) {
+            $requestEvent = new LogEvent();
+
+            $requestEvent->method = $request->getMethod();
+            $requestEvent->url = $request->getUri()->__toString();
+            $requestEvent->headers = $request->getHeaders();
+            $requestEvent->payload = $request->getBody()->getContents();
+            $requestEvent->retryAttempt = $options['retryAttempt'] ?? null;
+            $requestEvent->serviceName = $options['serviceName'] ?? null;
+            $requestEvent->clientId = spl_object_id($this->client);
+            $requestEvent->requestId = spl_object_id($request);
+
+            $this->logRequest($requestEvent);
+        }
+
+        $response = $this->client->send($request, $options);
+
+        if ($this->logger) {
+            $responseEvent = new LogEvent($requestEvent->timestamp);
+
+            $responseEvent->headers = $response->getHeaders();
+            $responseEvent->payload = $response->getBody()->getContents();
+            $responseEvent->status = $response->getStatusCode();
+            $responseEvent->clientId = $requestEvent->clientId;
+            $responseEvent->requestId = $requestEvent->requestId;
+
+            $this->logResponse($responseEvent);
+        }
+
+        return $response;
     }
 
     /**
@@ -57,6 +100,41 @@ public function __invoke(RequestInterface $request, array $options = [])
      */
     public function async(RequestInterface $request, array $options = [])
     {
-        return $this->client->sendAsync($request, $options);
+        $requestEvent = null;
+
+        if ($this->logger) {
+            $requestEvent = new LogEvent();
+
+            $requestEvent->method = $request->getMethod();
+            $requestEvent->url = $request->getUri()->__toString();
+            $requestEvent->headers = $request->getHeaders();
+            $requestEvent->payload = $request->getBody()->getContents();
+            $requestEvent->retryAttempt = $options['retryAttempt'] ?? null;
+            $requestEvent->serviceName = $options['serviceName'] ?? null;
+            $requestEvent->clientId = spl_object_id($this->client);
+            $requestEvent->requestId = spl_object_id($request);
+
+            $this->logRequest($requestEvent);
+        }
+
+        $promise = $this->client->sendAsync($request, $options);
+
+        if ($this->logger) {
+            $promise->then(function (ResponseInterface $response) use ($requestEvent) {
+                $responseEvent = new LogEvent($requestEvent->timestamp);
+
+                $responseEvent->headers = $response->getHeaders();
+                $responseEvent->payload = $response->getBody()->getContents();
+                $responseEvent->status = $response->getStatusCode();
+                $responseEvent->clientId = $requestEvent->clientId;
+                $responseEvent->requestId = $requestEvent->requestId;
+
+                $this->logResponse($responseEvent);
+
+                return $response;
+            });
+        }
+
+        return $promise;
     }
 }

src/HttpHandler/HttpHandlerFactory.php

@@ -16,22 +16,28 @@
  */
 namespace Google\Auth\HttpHandler;
 
+use Google\Auth\ApplicationDefaultCredentials;
 use GuzzleHttp\BodySummarizer;
 use GuzzleHttp\Client;
 use GuzzleHttp\ClientInterface;
 use GuzzleHttp\HandlerStack;
 use GuzzleHttp\Middleware;
+use Psr\Log\LoggerInterface;
 
 class HttpHandlerFactory
 {
     /**
      * Builds out a default http handler for the installed version of guzzle.
      *
      * @param ClientInterface $client
+     * @param null|false|LoggerInterface $logger
      * @return Guzzle6HttpHandler|Guzzle7HttpHandler
      * @throws \Exception
      */
-    public static function build(ClientInterface $client = null)
+    public static function build(
+        ClientInterface $client = null,
+        null|false|LoggerInterface $logger = null,
+    )
     {
         if (is_null($client)) {
             $stack = null;
@@ -45,6 +51,12 @@ public static function build(ClientInterface $client = null)
             $client = new Client(['handler' => $stack]);
         }
 
+        if ($logger === false) {
+            $logger = null;
+        } else {
+            $logger = $logger ?? ApplicationDefaultCredentials::getDefaultLogger();
+        }
+
         $version = null;
         if (defined('GuzzleHttp\ClientInterface::MAJOR_VERSION')) {
             $version = ClientInterface::MAJOR_VERSION;
@@ -54,9 +66,9 @@ public static function build(ClientInterface $client = null)
 
         switch ($version) {
             case 6:
-                return new Guzzle6HttpHandler($client);
+                return new Guzzle6HttpHandler($client, $logger);
             case 7:
-                return new Guzzle7HttpHandler($client);
+                return new Guzzle7HttpHandler($client, $logger);
             default:
                 throw new \Exception('Version not supported');
         }