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Plugin Manager Implementation

When to Use

Use plugin manager for Foundation+Extension and Provider Plugin patterns. Use service collector for Service Collector pattern. Choose based on whether you need annotation-based discovery (plugin manager) or tagged service discovery (service collector).

Decision

Situation Choose Why
Annotation-based plugin discovery Plugin Manager Scan directories for @PluginID annotations
Multiple configured instances Plugin Manager createInstance() with configuration array
Plugin alterations needed Plugin Manager Support for hook_plugin_info_alter
Simple tagged service aggregation Service Collector Auto-discovered during container compilation
REST API-first architecture Service Collector Built-in JSON serialization

Pattern

Plugin Manager Registration:

# module.services.yml
services:
  _defaults:
    autowire: true

  # Foundation Pattern - Multiple Managers
  plugin.manager.foundation_service_gateway:
    class: Drupal\foundation_module\ServiceGatewayManager
    parent: default_plugin_manager

  # Provider Pattern - Single Manager with Proxy
  my_module.service_provider:
    class: Drupal\my_module\ServiceProviderPluginManager
    parent: default_plugin_manager
    arguments: ['@service_container']

Service Collector Registration:

# Service Collector Pattern - Manager with Tagged Collection
services:
  orchestration.services_manager:
    class: Drupal\orchestration\ServicesProviderManager
    tags:
      - { name: 'service_collector', tag: 'orchestration_services_provider', call: 'addServicesProvider' }

Plugin Manager Key Methods: - getDefinitions() - Get all plugin definitions - createInstance($plugin_id, array $configuration) - Instantiate plugin - hasDefinition($plugin_id) - Check if plugin exists

Service Collector Key Methods: - addServicesProvider(ServicesProviderInterface $provider) - Called by service collector - getAllServices() - Aggregate services from all providers - executeService($serviceId, array $config) - Execute specific service

Common Mistakes

  • Wrong: Using plugin manager for stateless REST API services → Right: Use service collector with tagged services
  • Wrong: Not calling hasDefinition() before createInstance() → Right: Check existence to avoid expensive exception handling
  • Wrong: Multiple service collector tags on one service → Right: One tag per service, manager aggregates across all tagged services

See Also