Python concurrency example

concurrency.py

import time  # I will use it to simulate latency with time.sleep
from concurrent.futures import ThreadPoolExecutor, as_completed

def has_facebook_account(user_email):
    time.sleep(5)  # 5 seconds! That is bad.
    print("Finished facebook after 5 seconds!")
    return True

def has_github_account(user_email):
    time.sleep(1)  # 1 second. Phew!
    print("Finished github after 1 second!")
    return True

def has_twitter_account(user_email):
    time.sleep(3)  # Well...
    print("Finished twitter after 3 seconds!")
    return False

# Main method that answers if an user has an account in any of the platforms
def has_social_account(user_email):
    # ThreadPoolExecutor is a subclass of Executor that uses threads.
    # max_workers is the max number of threads that will be used.
    # Since we are scheduling only 3 tasks, it does not make sense to have
    # more than 3 threads, otherwise we would be wasting resources.
    executor = ThreadPoolExecutor(max_workers=3)

    # Schedule (submit) 3 tasks (one for each social account check)
	# .submit method returns a Future object
    facebook_future = executor.submit(has_facebook_account, user_email)
    twitter_future = executor.submit(has_twitter_account, user_email)
    github_future = executor.submit(has_github_account, user_email)
    future_list = [facebook_future, github_future, twitter_future]

	# as_completed receives an iterable of Future objects
    # and yields each future once it has been completed.
    for future in as_completed(future_list):
        # .result() returns the future object return value
        future_return_value = future.result()
        print(future_return_value)
        if future_return_value is True:
            # I can early return once any result is True
            return True

user_email = "[email protected]"
if __name__ == '__main__':
    has_social_account(user_email)