The Plugin Manager

What is the Plugin Manager?

The Plugin Manager is the orchestrator of GL Plugin. It's the central coordinator that wires everything together—handlers, services, and plugins. While it powers the entire system, you interact with it through a simple interface.

The Plugin Manager's role: Mermaid Link

The Manager is responsible for:

• Holding handlers that define plugin behavior

• Storing global services shared across all plugins

• Maintaining the Service Registry that resolves injections

• Registering and retrieving plugins

---

Creating a Manager

from gl_plugin.plugin.manager import PluginManager

manager = PluginManager(
    handlers=[handler_a, handler_b],
    global_services=[config_service, cache_service],
)

Parameter	Description
handlers	List of handler instances that manage plugins
global_services	List of service instances available to all plugins

---

Registering Plugins

Use register_plugin() to add plugins to the manager:

manager.register_plugin(AddPlugin)
manager.register_plugin(SubtractPlugin)
manager.register_plugin(MultiplyPlugin)

When you register a plugin, the manager:

Plugin Registration Flow: Mermaid Link

1. Identifies which handler the plugin belongs to (via @Plugin.for_handler())

2. Collects services from the handler and global services

3. Creates the plugin instance (__new__)

4. Injects services into the instance

5. Calls the handler's initialize_plugin() method

6. Stores the plugin for later retrieval

---

Retrieving Plugins

By Name

Retrieve a specific plugin using its name attribute:

add_plugin = manager.get_plugin("AddPlugin")
result = add_plugin.calculate(10, 5)

By Handler Type

Retrieve all plugins managed by a specific handler:

plugins = manager.get_plugins(CalculatorHandler)

for plugin in plugins:
    print(f"{plugin.name}: {plugin.calculate(20, 4)}")

This is useful for:

• Processing all plugins of a category

• Polymorphic operations across related plugins

• Plugin discovery and introspection

---

Manager Lifecycle

The Lifecycle Diagram for Plugin Manager: Mermaid Link

Complete Example

from gl_plugin.plugin.manager import PluginManager

# 1. Setup
handler = CalculatorHandler(precision=3)
config = ConfigService()
cache = CacheService()

manager = PluginManager(
    handlers=[handler],
    global_services=[config, cache],
)

# 2. Registration
manager.register_plugin(AddPlugin)
manager.register_plugin(SubtractPlugin)
manager.register_plugin(MultiplyPlugin)

# 3. Usage
# By name
add = manager.get_plugin("AddPlugin")
print(add.calculate(10, 5))  # 15.0

# By handler type
for plugin in manager.get_plugins(CalculatorHandler):
    print(f"{plugin.name}: {plugin.calculate(100, 10)}")

---

Summary

Method	Description
PluginManager(handlers, global_services)	Create manager with handlers and global services
register_plugin(PluginClass)	Register a plugin class
get_plugin(name)	Retrieve a plugin by its name
get_plugins(HandlerType)	Retrieve all plugins for a handler type