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Addon Life cycle

🚀 Extending Your Addon: Lifecycle Hooks with AddonSetupHook

Let’s continue working on our hello_world addon to demonstrate how to define custom behaviors during the addon lifecycle. When pAPI discovers an addon, you can control its startup and shutdown phases. This is especially useful when you need to perform certain actions before the system starts, or just before it shuts down.

Each addon can, optionally, register one or more AddonSetupHook classes to manage its lifecycle events. In this tutorial, we’ll implement a basic AddonSetupHook to simulate tasks executed during addon startup and shutdown.

1️⃣ Add the Setup File to Your Addon

Inside your hello_world addon directory, create a new Python file named addon_setup.py (or any other name you prefer). Your addon structure should look like this:

my_addons/
└── hello_world/
    ├── __init__.py
    ├── manifest.yaml
    ├── addon_setup.py
    └── routers.py

2️⃣ Define the AddonSetupHook

Now, import AddonSetupHook and subclass it. You’ll need to implement the asynchronous startup and shutdown methods. Here’s a basic example that simulates some heavy async tasks using sleep:

from asyncio import sleep
from logging import getLogger

from papi.core.addons import AddonSetupHook

logger = getLogger(__name__)


class HelloWorldAddonSetup(AddonSetupHook):
    async def startup(self):
        logger.info("Initializing 'Hello World' addon...")
        await sleep(10)  # Simulate a heavy async task at startup
        logger.info("'Hello World' addon setup completed.")

    async def shutdown(self):
        logger.info("Shutting down 'Hello World' addon...")
        await sleep(5)  # Simulate a heavy async task at shutdown
        logger.info("'Hello World' addon shutdown completed.")

3️⃣ Register the Hook in __init__.py

Finally, import your HelloWorldAddonSetup class in the addon's __init__.py so that pAPI can discover and register it automatically:

from .router import router as hello_router
from .addon_setup import HelloWorldAddonSetup

That’s all you need!

When the addon is loaded, the startup method will be executed automatically. When the application is stopped (e.g. by pressing Ctrl+C while running with uvicorn), the shutdown method will be called.