Python 비동기 프로그래밍 시작하기: I/O 바운드 작업 효율화 가이드

import asyncio
import time

async def download_file(name, seconds):
    print(f"Starting {name}")
    await asyncio.sleep(seconds)
    print(f"Finished {name}")

async def main():
    start = time.perf_counter()
    await asyncio.gather(
        download_file("file-1", 2),
        download_file("file-2", 2),
        download_file("file-3", 2),
    )
    end = time.perf_counter()
    print(f"[TOTAL ASYNC] took {end - start:.4f} seconds")

asyncio.run(main())

async def fetch(url):
    start = time.perf_counter()
    print(f"Fetching {url}")
    # Run blocking IO in a thread
    data = await asyncio.to_thread(fetch_sync, url)
    elapsed = time.perf_counter() - start
    print(f"Finished {url} in {elapsed:.2f} seconds")
    return data

semaphore = asyncio.Semaphore(2)

async def task(task_id):
    async with semaphore:
        print(f"Task {task_id} started")
        await asyncio.sleep(2)
        print(f"Task {task_id} finished")