Python AsyncIO Patterns Cheat Sheet

Last Updated: November 21, 2025

Focus Areas

Pattern	Why it matters
`TaskGroup`	Structured concurrency that cancels all children together.
`shield()`	Protect cleanup from being canceled with the caller.
`contextvars`	Pass request-scoped data without relying on globals.
`asyncio.run()`	Create and close an event loop in scripts safely.


         asyncio.create_task(coro)

Launch a background unit of work while the parent continues.


         asyncio.TaskGroup()

`async with TaskGroup()` keeps child tasks scoped together.


         await asyncio.wait_for(task, timeout=5)

Enforce deadlines and handle TimeoutError.


         await asyncio.shield(cleanup())

Let cleanup finish even if the surrounding task cancels.

Favor TaskGroup/async context managers for predictable cleanup, add shielding when canceling, and propagate metadata through context variables.

💡 Pro Tip: Use TaskGroup/async context managers so canceled parents always wait for their children.