Advanced Python Tutorial: Asynchronous Programming

Advanced Python Tutorial 6: Asynchronous Programming

🧠 What is Asynchronous Programming?

Asynchronous programming allows your program to handle multiple tasks at once, especially useful when dealing with I/O-bound operations such as reading files or calling web APIs. It improves performance and responsiveness.

🔄 Sync vs Async

Synchronous: Tasks are executed one after another — the next waits for the current to finish.

Asynchronous: Tasks can be paused and resumed, allowing others to run concurrently, especially during waiting periods.

🧪 Basic Example with asyncio

Let’s demonstrate using Python’s built-in asyncio module to run two asynchronous tasks.

🚀 Full Code Example

import asyncio

async def task(name, delay):
    print(f"{name} started")
    await asyncio.sleep(delay)
    print(f"{name} finished after {delay}s")

async def main():
    await asyncio.gather(
        task("Task 1", 2),
        task("Task 2", 1)
    )

asyncio.run(main())
    

Output: Task 2 finishes first even though it's written after Task 1, because it has a shorter delay.

📌 When to Use Async?

• Making multiple API requests simultaneously
• Reading/writing to files or databases
• Handling web requests in frameworks like FastAPI or aiohttp

✅ Summary

• async def defines an asynchronous function.
• await pauses the function until the awaited task completes.
• asyncio.gather runs tasks concurrently.