billiard_pool_parallel_map_async_worker_processes.py

1from billiard import Pool
2
3def f(x):
4    return x*x
5
6if __name__ == '__main__':
7    with Pool(processes=4) as pool:         # start 4 worker processes
8        result = pool.apply_async(f, (10,)) # evaluate "f(10)" asynchronously in a single process
9        print(result.get(timeout=1))        # prints "100"
10
11        print(pool.map(f, range(10)))       # prints "[0, 1, 4, 9, 16, 25, 36, 49, 64, 81]"
12
13        it = pool.imap(f, range(10))
14        print(next(it))                     # prints "0"
15        print(next(it))                     # prints "1"
16        print(it.next(timeout=1))           # prints "4"
17
18        import time
19        result = pool.apply_async(time.sleep, (10,))
20        print(result.get(timeout=1))        # raises billiard.exceptions.TimeoutError