Python使用asyncio把接口耗时从30秒压到3秒的示例代码

import requests, time

def fetch(url):
    return requests.get(url, timeout=5).json()

start = time.time()
data = [fetch(u) for u in URLS]   # 30 个串行请求
print(time.time() - start)        # 约 30s

import asyncio, aiohttp, time

URLS = [f"[https://httpbin.org/delay/1?n={i}](https://httpbin.org/delay/1?n={i})" for i in range(30)]
CONCURRENCY = 10          # 单域名并发上限，避免压垮对端

async def fetch(session, url, sem):
    async with sem:                       # 限流
        async with session.get(url, timeout=5) as resp:
            return await resp.json()

async def main():
    sem = asyncio.Semaphore(CONCURRENCY)
    timeout = aiohttp.ClientTimeout(total=5)
    async with aiohttp.ClientSession(timeout=timeout) as session:
        tasks = [fetch(session, u, sem) for u in URLS]
        results = await asyncio.gather(*tasks, return_exceptions=True)
    ok = [r for r in results if not isinstance(r, Exception)]
    print(f"成功 {len(ok)} / {len(URLS)}")
    return ok

if __name__ == "__main__":
    start = time.time()
    asyncio.run(main())
    print(f"总耗时 {time.time() - start:.2f}s")   # 约 3.2s

async def fetch_with_retry(session, url, sem, retry=2):
    for attempt in range(retry + 1):
        try:
            async with sem:
                async with asyncio.timeout(5):
                    async with session.get(url) as resp:
                        resp.raise_for_status()
                        return await resp.json()
        except (asyncio.TimeoutError, aiohttp.ClientError):
            if attempt == retry:
                raise
            await asyncio.sleep(2 ** attempt)   # 指数退避