python - 在 python 中等待之前，不会在异步函数中调用打印函数

Question

我想获得一些与请求和 asyncio 的链接。我有一个示例程序，但我认为存在问题，因为只有在我使用 await 时才会调用打印函数。

那么为什么在我调用实际函数的地方不调用 print 呢？据我了解，如果使用 await 关键字，该函数会中断，直到 future 出现。在我的例子中，打印函数应该在 await 关键字之前被调用，所以在打印语句之前:doing stuff in between还是我错了？

import asyncio
import requests
import bs4

urls = ["http://www.google.com", "http://www.google.co.uk"]

async def getContent(url):
    loop = asyncio.get_event_loop()
    print("getting content for: " + url) # print should be called here
    # execute a non async function async
    future = loop.run_in_executor(None, requests.get, url)

    # doing stuff with bs4
    soup = bs4.BeautifulSoup((await future).text, "html.parser") # should now interrupt

    return soup 

async def main():
    loop = asyncio.get_event_loop()

    print("starting gathering...")
    # creating a list of futures
    futures = [getContent(url) for url in urls]
    # packing futures into a awaitable list future
    responses_future = asyncio.gather(*futures)

    print("doing stuff in between...")
    # waiting for all futures
    responses = await responses_future

    print("Done")

    for response in responses:
        print(response)

loop = asyncio.get_event_loop()
loop.run_until_complete(main())

输出:

starting gathering...
doing stuff in between...
getting content for: http://www.google.com
getting content for: http://www.google.co.uk
Done

HTML CODE HERE!

问候

Answer 1

协程在等待之前不会被执行，这就是它发生的原因