Openfeature Configcat Bundle Laravel Package

Getting Started

Minimal Setup

1. Install the bundle:

   composer require aubes/openfeature-configcat-bundle
   

   Manually register the bundle in config/bundles.php if Symfony Flex isn't used:

   Aubes\OpenFeatureConfigCatBundle\OpenFeatureConfigCatBundle::class => ['all' => true],
   

2. Configure the bundle in config/packages/open_feature_configcat.yaml:

   open_feature_config_cat:
       sdk_key: '%env(CONFIGCAT_SDK_KEY)%'
   

   Ensure CONFIGCAT_SDK_KEY is set in your .env file.

3. First use case: Fetch a feature flag in a service:

   use ConfigCat\OpenFeature\ConfigCatProvider;
   use OpenFeature\OpenFeatureAPI;
   
   class FeatureService {
       public function __construct(private ConfigCatProvider $provider) {}
   
       public function toggleDarkMode(): bool {
           return OpenFeatureAPI::getInstance()
               ->setProvider($this->provider)
               ->getClient()
               ->getBooleanValue('dark_mode', false);
       }
   }
   

Implementation Patterns

Dependency Injection

• Inject ConfigCatProvider directly into services for OpenFeature API access.
• Leverage Symfony’s container to manage provider lifecycle (e.g., caching, logging).

Integration with OpenFeature Bundle (Optional)

If using aubes/openfeature-bundle, configure it to use this provider:

# config/packages/open_feature.yaml
open_feature:
    provider: ConfigCat\OpenFeature\ConfigCatProvider

This unlocks:

• Attributes (#[FeatureFlag], #[FeatureGate]).
• Twig helpers (e.g., feature_flag()).
• Request-scoped evaluation (e.g., user-specific flags).

Flag Overrides

Use local overrides for development/testing:

open_feature_config_cat:
    flag_overrides:
        type: file
        path: '%kernel.project_dir%/config/feature_flags.json'
        behaviour: local_over_remote  # Overrides remote flags

HTTP Client Customization

Replace Guzzle with Symfony’s HttpClient (PSR-18):

# config/services.yaml
services:
    Aubes\OpenFeatureConfigCatBundle\Http\Psr18FetchClient:
        arguments:
            $client: '@psr18.http_client'
            $requestFactory: '@Psr\Http\Message\RequestFactoryInterface'

# config/packages/open_feature_configcat.yaml
open_feature_config_cat:
    fetch_client: Aubes\OpenFeatureConfigCatBundle\Http\Psr18FetchClient

Gotchas and Tips

Pitfalls

1. Missing SDK Key:

   • If sdk_key is omitted, the provider will fail silently. Validate in config/validator.yaml:

     services:
         _defaults:
             autowire: true
             bind:
                 ConfigCat\OpenFeature\ConfigCatProvider::class: '@open_feature_config_cat.provider'
     

   • Add a runtime check:

     if (empty($provider->getSdkKey())) {
         throw new \RuntimeException('ConfigCat SDK key not configured.');
     }
     

2. Caching Conflicts:

   • Avoid mixing cache and cache_pool in config. They are mutually exclusive.

3. Offline Mode:

   • Set offline: true for development, but ensure flag_overrides are configured to avoid empty flag evaluations.

Debugging

• Enable Logging:

  open_feature_config_cat:
      logger: '@monolog.logger.configcat'
  

  Logs will include flag evaluation details and fetch errors.

• Check Cache: If flags aren’t updating, verify the cache_refresh_interval (default: 60s) and clear the cache:

  php bin/console cache:clear
  

Extension Points

1. Custom Fetch Client: Implement ConfigCat\Http\FetchClientInterface for custom HTTP logic (e.g., retries, proxies).

2. Override Data Sources: For dynamic overrides, inject a service:

   open_feature_config_cat:
       flag_overrides:
           type: service
           id: 'app.feature_flag_override_service'
   

3. Data Governance: Use data_governance: eu_only to comply with GDPR by hosting data in the EU.

Performance Tips

• Batch Evaluations: Use getBooleanValues(), getStringValues(), etc., to fetch multiple flags in one request.
• Lazy Initialization: Defer provider setup until first use to avoid blocking bootstrapping:

  OpenFeatureAPI::getInstance()->setProvider($provider);
  

Testing

• Mock the Provider:

  $provider = $this->createMock(ConfigCatProvider::class);
  $provider->method('getBooleanValue')->willReturn(true);
  OpenFeatureAPI::getInstance()->setProvider($provider);
  

• Use Offline Mode: Test locally with offline: true and flag_overrides to avoid network calls.