Async Python Patterns in Home Assistant

Home Assistant runs on a single-threaded asyncio event loop. All I/O must be non-blocking. Blocking the loop freezes automations, the UI, and entity updates.

Pattern 1: Async Libraries (Preferred)

import aiohttp

async def async_get_data(self) -> dict:
    async with aiohttp.ClientSession() as session:
        async with session.get(f"http://{self._host}/api") as response:
            response.raise_for_status()
            return await response.json()

Pattern 2: Wrapping Sync Libraries

When no async library exists: