README.md

Module 093: Asynchronous Python: asyncio

• Phase: 10. Concurrency & Internals
• Duration: 2.5 hours

Learning Objectives

• Write async code using async/await syntax
• Understand the event loop and how it drives coroutines
• Create and manage tasks with asyncio.create_task and asyncio.gather
• Recognize awaitable objects (coroutines, tasks, futures)
• Perform async I/O with aiohttp
• Decide when async helps (I/O-bound vs CPU-bound)

Topics Covered

1. async/await syntax
2. Event loop
3. Coroutines
4. Tasks: asyncio.create_task, asyncio.gather
5. Awaitable objects
6. asyncio.sleep for cooperative yielding
7. Running async code: asyncio.run
8. aiohttp for async HTTP
9. I/O-bound vs CPU-bound decisions

Prerequisites

Modules 000-092.

Key Concepts

import asyncio
from typing import List

async def fetch(url: str) -> str:
    await asyncio.sleep(0.1)
    return f"Data from {url}"

async def main() -> None:
    tasks: List[asyncio.Task] = [
        asyncio.create_task(fetch(f"https://api.example.com/{i}"))
        for i in range(5)
    ]
    results: List[str] = await asyncio.gather(*tasks)
    print(results)

asyncio.run(main())

Resources

• Python asyncio documentation
• aiohttp documentation
• "Using asyncio" by Caleb Hattingh (O'Reilly)

Next Module

Module 094: Memory Management & Garbage Collection in CPython