[python]requests VS httpx VS aiohttp

前言

前段时间想着把一个python服务的接口逐渐改成异步的，其中用到requests的地方就要改成httpx或者aiohttp，有点好奇异步请求相较于同步请求有哪些提升，遂做了点小实验。

首先有个服务A提供接口，这个接口会停顿1秒，模拟数据库操作。服务B去请求服务A的这个接口，并把响应返回给客户端C。服务B提供4个接口，这4个接口分别用requests、httpx同步、httpx异步和aiohttp去请求服务A。

客户端使用wrk做请求测试。

实现服务A

服务A使用Go编写，用标准库即可完成

package main
import (
	"net/http"
	"time"
)
func main() {
	mux := http.NewServeMux()
	mux.HandleFunc("GET /a", func(w http.ResponseWriter, r *http.Request) {
	time.Sleep(1 * time.Second)
	w.Write([]byte("ok"))
	})
	if err := http.ListenAndServe("127.0.0.1:8000", mux); err != nil {
	panic(err)
	}
}

先用wrk直接请求试试，以此作为基准

$ wrk -t8 -c1000 -d30s http://127.0.0.1:8000/a
Running 30s test @ http://127.0.0.1:8000/a
 8 threads and 1000 connections
 Thread Stats Avg Stdev Max +/- Stdev
 Latency 1.00s 7.62ms 1.17s 97.34%
 Req/Sec 194.17 266.07 1.24k 86.82%
 29491 requests in 30.10s, 3.32MB read
Requests/sec: 979.85
Transfer/sec: 112.91KB

服务B: FastAPI

先用FastAPI做服务B试试

from fastapi import FastAPI
import httpx
import aiohttp
import uvicorn
import requests
app = FastAPI()
url = "http://127.0.0.1:8000/a"
@app.get("/sync1")
def sync1():
 try:
 resp = requests.get(url, timeout=2)
 resp.raise_for_status()
 except Exception as e:
 print(f"sync request failed, {e}")
 else:
 return resp.text
 
@app.get("/sync2")
def sync2():
 try:
 with httpx.Client() as client:
 resp = client.get(url, timeout=2)
 resp.raise_for_status()
 except Exception as e:
 print(f"sync2 request failed, {e}")
 else:
 return resp.text
 
@app.get("/async1")
async def async1():
 try:
 async with httpx.AsyncClient(timeout=2) as client:
 resp = await client.get(url)
 resp.raise_for_status()
 except Exception as e:
 print(f"async1 request failed, {e}")
 else:
 return resp.text
 
@app.get("/async2")
async def async2():
 try:
 async with aiohttp.ClientSession() as session:
 async with session.get(url, timeout=2) as resp:
 resp.raise_for_status()
 content = await resp.text()
 except Exception as e:
 print(f"async2 request failed, {e}")
 else:
 return content
 
if __name__ == "__main__":
 uvicorn.run("server1:app", host="127.0.0.1", port=8001, workers=4, access_log=False)

wrk请求结果。httpx不仅同步请求性能不如requests，没想到连异步请求性能也不如requests。而aiohttp以五倍多第二名的性能冠绝群雄。

异步比同步性能还差，着实有点费解，遂找大模型问了下，大模型回复说httpx默认配置参数不高，可以额外指定参数，还需要避免反复创建http client。似乎有点道理，但是同步性能不如开箱即用的requests，异步性能不如开箱即用的aiohttp，我为什么还要折腾httpx呢？

服务B: Flask

Flask 2.0 也支持异步接口，但是之前测试性能并不是很好，拉出来一并测试瞧瞧实力。

Flask 版本：3.1.1。因为gunicorn运行异步接口会报错，所以用的flask内置webserver。

from flask import Flask
import requests
import httpx
import logging
import aiohttp
app = Flask(__name__)
url = "http://127.0.0.1:8000/a"
@app.get("/sync1")
def sync1():
 try:
 resp = requests.get(url, timeout=2)
 resp.raise_for_status()
 except Exception as e:
 print("request failed")
 return "request failed"
 else:
 return resp.text
 
@app.get("/sync2")
def sync2():
 try:
 with httpx.Client() as client:
 resp = client.get(url, timeout=2)
 resp.raise_for_status()
 except Exception as e:
 print("request failed")
 return "request failed"
 else:
 return resp.text
@app.get("/async1")
async def async1():
 try:
 async with httpx.AsyncClient(timeout=2) as client:
 resp = await client.get(url, timeout=2)
 resp.raise_for_status()
 except Exception as e:
 print("request failed")
 return "request failed"
 else:
 return resp.text
 
@app.get("/async2")
async def async2():
 try:
 async with aiohttp.ClientSession() as session:
 async with session.get(url, timeout=2) as response:
 response.raise_for_status()
 resp = await response.text()
 except Exception as e:
 print("request failed")
 return "request failed"
 else:
 return resp
 
if __name__ == "__main__":
 werkzeug_logger = logging.getLogger("werkzeug")
 werkzeug_logger.disabled = True
 app.run(host="127.0.0.1", port=8001)

测试结果。看来flask还是跟requests更搭，异步还不如同步。

服务B: Sanic

再用Sanic测试一遍

from sanic import Sanic
from sanic.response import text
import requests
import httpx
import aiohttp
app = Sanic(__name__)
url = "http://127.0.0.1:8000/a"
@app.get("/sync1")
def sync1(request):
 try:
 resp = requests.get(url, timeout=2)
 resp.raise_for_status()
 except Exception as e:
 print(f"sync1 request failed, {e}")
 else:
 return text(resp.text)
@app.get("/sync2")
def sync2(request):
 try:
 with httpx.Client() as client:
 response = client.get(url, timeout=2)
 response.raise_for_status()
 except Exception as e:
 print(f"sync2 request failed, {e}")
 else:
 return text(response.text)
@app.get("/async1")
async def async1(request):
 try:
 async with httpx.AsyncClient() as client:
 response = await client.get(url, timeout=2)
 response.raise_for_status()
 except Exception as e:
 print(f"async1 request failed, {e}")
 else:
 return text(response.text)
@app.get("/async2")
async def async2(request):
 try:
 async with aiohttp.ClientSession() as session:
 async with session.get(url, timeout=2) as response:
 response.raise_for_status()
 content = await response.text()
 except Exception as e:
 print(f"async2 request failed, {e}")
 else:
 return text(content)
if __name__ == "__main__":
 app.run(host="127.0.0.1", port=8001, debug=False, access_log=False, workers=4)

可能是我对Sanic了解不多，单就这个测试结果来看，Sanic根本不适合编写同步API。而且使用httpx异步请求的时候有大量报错，wrk结果显示 Non-2xx or 3xx responses: 1244

服务B: Go

最后再用Go实现下请求

func GetA(w http.ResponseWriter, r *http.Request) {
	resp, err := http.Get("http://127.0.0.1:8000/a")
	if err != nil {
	log.Println(err)
	}
	defer resp.Body.Close()
	body, err := io.ReadAll(resp.Body)
	if err != nil {
	log.Println(err)
	}
	w.Write(body)
}
func main() {
	mux := http.NewServeMux()
	mux.HandleFunc("GET /b", GetA)
	if err := http.ListenAndServe("127.0.0.1:8001", mux); err != nil {
	panic(err)
	}
}

测试结果，和直接请求服务A差别不大。

$ wrk -t8 -c1000 -d30s http://127.0.0.1:8001/b
Running 30s test @ http://127.0.0.1:8001/b
 8 threads and 1000 connections
 Thread Stats Avg Stdev Max +/- Stdev
 Latency 1.02s 85.69ms 1.66s 96.55%
 Req/Sec 210.49 175.05 740.00 63.65%
 29000 requests in 30.08s, 3.26MB read
Requests/sec: 963.97
Transfer/sec: 111.08KB

小结

用python编写同步请求还是老老实实用requests，异步接口应该用aiohttp，httpx的性能只能说能用。