python - 如何使用 aiohttp 确定每秒请求数？

Question

我正在尝试使用 aiohttp 创建网络流量模拟器。以下代码示例异步发出 10k 个请求。我想知道其中有多少是同时发生的，所以我可以说这模拟了 10k 用户同时请求一个网站。

我如何确定并发网络请求的数量，或者我如何确定 aiohttp 每秒发出多少请求？有没有办法实时调试/分析并发请求数？

有没有更好的方法来使用任何其他编程语言为网络流量模拟器建模？

import asyncio
import aiohttp

async def fetch(session, url):
  with aiohttp.Timeout(10, loop=session.loop):
      async with session.get(url) as response:
            return await response.text()

async def run(r):
    url = "http://localhost:3000/"
    tasks = []

    # Create client session that will ensure we dont open new connection
    # per each request.
    async with aiohttp.ClientSession() as session:
        for i in range(r):
          html = await fetch(session, url)
          print(html)


# make 10k requests per second ?? (not confident this is true)
number = 10000
loop = asyncio.get_event_loop()
loop.run_until_complete(run(number))

Answer 1

你好，首先在原始代码中有一个错误:

async with aiohttp.ClientSession() as session:
    for i in range(r):
      # This line (the await part) makes your code wait for a response
      # This means you done 1 concurent request
      html = await fetch(session, url)

如果你修复了这个错误，你就会得到你想要的——所有的请求都会同时开始。

除非使用 Semaphore/Queue，否则您将对服务进行锤击。

无论如何，如果这是你想要的，你可以使用这个:

import asyncio
import aiohttp
import tqdm


async def fetch(session, url):
    with aiohttp.Timeout(10, loop=session.loop):
        async with session.get(url) as response:
            return await response.text()


async def run(r):
    url = "http://localhost:3000/"
    tasks = []
    # The default connection is only 20 - you want to stress...
    conn = aiohttp.TCPConnector(limit=1000)
    tasks, responses = [], []
    async with aiohttp.ClientSession(connector=conn) as session:
        tasks = [asyncio.ensure_future(fetch(session, url)) for _ in range(r)]
        #This will show you some progress bar on the responses 
        for f in tqdm.tqdm(asyncio.as_completed(tasks), total=len(tasks)):
            responses.append(await f)
    return responses

number = 10000
loop = asyncio.get_event_loop()
loop.run_until_complete(run(number))

感谢asyncio aiohttp progress bar with tqdm对于 tqdm :)

我还建议阅读 https://pawelmhm.github.io/asyncio/python/aiohttp/2016/04/22/asyncio-aiohttp.html以便更好地了解协程的工作原理。