Modern Python Standard Library Cookbook

How to do it...

The steps for this recipe are as follows:

1. To showcase how ThreadPool works, we will need two operations that we want to run concurrently. One will fetch a URL from the web, which might take some time:

def fetch_url(url):
    """Fetch content of a given url from the web"""
    import urllib.request
    response = urllib.request.urlopen(url)
    return response.read()

2. The other will just wait for a given condition to be true, looping over and over until it's done:

def wait_until(predicate):
    """Waits until the given predicate returns True"""
    import time
    seconds = 0
    while not predicate():
        print('Waiting...')
        time.sleep(1.0)
        seconds += 1
    print('Done!')
    return seconds

3. Then we will just fire the download for https://httpbin.org/delay/3, which ...