All 15 Concurrency (asyncio/threading/multiprocessing) questions
More in Concurrency (asyncio/threading/multiprocessing)
What is the fundamental difference between concurrency and parallelism, and how does this map to Python's threading versus multiprocessing modules? How do you create and run a basic thread using the threading module? How does the Global Interpreter Lock (GIL) affect CPU-bound versus I/O-bound multithreaded programs differently? How do you run multiple coroutines concurrently using asyncio.gather()? How do you protect shared mutable state from race conditions when using multiple threads, using threading.Lock? How does multiprocessing.Pool let you parallelize a CPU-bound function across multiple worker processes? What is a race condition, and how does it differ from a deadlock? How does asyncio's event loop schedule and switch between multiple coroutines, and what makes this cooperative rather than preemptive? How do you safely run a blocking, synchronous function from within an asyncio coroutine without freezing the event loop? How do you share data between processes using multiprocessing, given that separate processes don't share memory the way threads do?
Advertisement
Python › Concurrency (asyncio/threading/multiprocessing)

What is the basic pattern for running an async function using asyncio.run()?

Beginner

Answer

Define your entry-point coroutine with 'async def', then call asyncio.run(coroutine()) from regular (synchronous) code — this creates a new event loop, runs the coroutine to completion, and closes the loop, serving as the standard top-level entry point for an asyncio program.
import asyncio

async def main():
    print("Start")
    await asyncio.sleep(1)
    print("End")

asyncio.run(main())
Real-world example Running an async web scraper or API client script as the top-level entry point of a standalone Python program.

Common follow-ups: Why should asyncio.run() typically only be called ONCE, at the very top level of a program?

Async Generators & Async Context Managers
All 15 Concurrency (asyncio/threading/multiprocessing) questions