example-code-2e/20-executors/getflags/flags_threadpool_futures.py
2021-10-05 09:44:12 -03:00

32 lines
951 B
Python
Executable File

#!/usr/bin/env python3
"""Download flags of top 20 countries by population
ThreadPoolExecutor example with ``as_completed``.
"""
from concurrent import futures
from flags import main
from flags_threadpool import download_one
# tag::FLAGS_THREADPOOL_AS_COMPLETED[]
def download_many(cc_list: list[str]) -> int:
cc_list = cc_list[:5] # <1>
with futures.ThreadPoolExecutor(max_workers=3) as executor: # <2>
to_do: list[futures.Future] = []
for cc in sorted(cc_list): # <3>
future = executor.submit(download_one, cc) # <4>
to_do.append(future) # <5>
print(f'Scheduled for {cc}: {future}') # <6>
for count, future in enumerate(futures.as_completed(to_do), 1): # <7>
res: str = future.result() # <8>
print(f'{future} result: {res!r}') # <9>
return count
# end::FLAGS_THREADPOOL_AS_COMPLETED[]
if __name__ == '__main__':
main(download_many)