bug #423 [AiBundle][VertexAI] Fix service definition (valtzu)

This PR was merged into the main branch.

Discussion
----------

[AiBundle][VertexAI] Fix service definition

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| Docs?         | no
| Issues        | Fix #419
| License       | MIT

Fix a couple of VertexAI issues:

1. Bundle config was not working at all since instances were created build-time instead of building `Definition`s
2. Access token was fetched build-time

To add tests, we'd need to add `google/auth` to dev dependencies. If that's ok, I'll do that and remove exclusion from `phpstan.dist.neon`.

Commits
-------

bf7b9ab [AiBundle] Fix VertexAI services

Author: OskarStark

src/ai-bundle/composer.json

@@ -25,6 +25,7 @@
         "symfony/string": "^6.4 || ^7.0"
     },
     "require-dev": {
+        "google/auth": "^1.47",
         "phpstan/phpstan": "^2.1",
         "phpunit/phpunit": "^11.5",
         "symfony/expression-language": "^6.4 || ^7.0",

src/ai-bundle/src/AiBundle.php

@@ -12,6 +12,7 @@
 namespace Symfony\AI\AiBundle;
 
 use Google\Auth\ApplicationDefaultCredentials;
+use Google\Auth\FetchAuthTokenInterface;
 use Symfony\AI\Agent\Agent;
 use Symfony\AI\Agent\AgentInterface;
 use Symfony\AI\Agent\Attribute\AsInputProcessor;
@@ -75,7 +76,6 @@
 use Symfony\Component\DependencyInjection\Definition;
 use Symfony\Component\DependencyInjection\Loader\Configurator\ContainerConfigurator;
 use Symfony\Component\DependencyInjection\Reference;
-use Symfony\Component\HttpClient\EventSourceHttpClient;
 use Symfony\Component\HttpClient\HttpClient;
 use Symfony\Component\HttpKernel\Bundle\AbstractBundle;
 use Symfony\Component\Security\Core\Authorization\AuthorizationCheckerInterface;
@@ -281,13 +281,21 @@ private function processPlatformConfig(string $type, array $platform, ContainerB
                 throw new RuntimeException('For using the Vertex AI platform, google/auth package is required. Try running "composer require google/auth".');
             }
 
-            $credentials = ApplicationDefaultCredentials::getCredentials([
-                'https://www.googleapis.com/auth/cloud-platform',
-            ]);
+            $credentials = (new Definition(FetchAuthTokenInterface::class))
+                ->setFactory([ApplicationDefaultCredentials::class, 'getCredentials'])
+                ->setArguments([
+                    'https://www.googleapis.com/auth/cloud-platform',
+                ])
+            ;
 
-            $httpClient = new EventSourceHttpClient(HttpClient::create([
-                'auth_bearer' => $credentials?->fetchAuthToken()['access_token'] ?? null,
-            ]));
+            $credentialsObject = new Definition(\ArrayObject::class, [(new Definition('array'))->setFactory([$credentials, 'fetchAuthToken'])]);
+
+            $httpClient = (new Definition(HttpClientInterface::class))
+                ->setFactory([HttpClient::class, 'create'])
+                ->setArgument(0, [
+                    'auth_bearer' => (new Definition('string', ['access_token']))->setFactory([$credentialsObject, 'offsetGet']),
+                ])
+            ;
 
             $platformId = 'ai.platform.vertexai';
             $definition = (new Definition(Platform::class))

src/ai-bundle/tests/DependencyInjection/AiBundleTest.php

@@ -620,6 +620,10 @@ private function getFullConfig(): array
                     'voyage' => [
                         'api_key' => 'voyage_key_full',
                     ],
+                    'vertexai' => [
+                        'location' => 'global',
+                        'project_id' => '123',
+                    ],
                 ],
                 'agent' => [
                     'my_chat_agent' => [