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"""
Compare the speed of downloading URLs sequentially vs. using futures.
"""
import contextlib
import functools
import sys
import time
try:
from urllib.request import urlopen
except ImportError:
from urllib2 import urlopen
try:
from concurrent.futures import ThreadPoolExecutor
except ImportError:
ThreadPoolExecutor = lambda _: None # noqa: E731
try:
from concurrent.futures import ProcessPoolExecutor
except ImportError:
ProcessPoolExecutor = lambda _: None # noqa: E731
from mpi4py.futures import MPIPoolExecutor, as_completed
URLS = [
"http://www.google.com/",
"http://www.apple.com/",
"http://www.ibm.com",
"http://www.thisurlprobablydoesnotexist.com",
"http://www.slashdot.org/",
"http://www.python.org/",
"http://www.bing.com/",
"http://www.facebook.com/",
"http://www.github.com/",
"http://www.youtube.com/",
"http://www.blogger.com/",
]
def load_url(url, timeout):
return urlopen(url, timeout=timeout).read()
def download_urls_sequential(urls, timeout=60):
url_to_content = {}
for url in urls:
with contextlib.suppress(Exception):
url_to_content[url] = load_url(url, timeout=timeout)
return url_to_content
def download_urls_with_executor(executor, urls, timeout=60):
if executor is None:
return {}
try:
url_to_content = {}
future_to_url = {
executor.submit(load_url, url, timeout): url for url in urls
}
for future in as_completed(future_to_url):
with contextlib.suppress(Exception):
url_to_content[future_to_url[future]] = future.result()
return url_to_content
finally:
executor.shutdown()
def main():
for meth, fn in [
("sequential", functools.partial(download_urls_sequential, URLS)),
(
"threads",
functools.partial(
download_urls_with_executor, ThreadPoolExecutor(10), URLS
),
),
(
"processes",
functools.partial(
download_urls_with_executor, ProcessPoolExecutor(10), URLS
),
),
(
"mpi4py",
functools.partial(
download_urls_with_executor, MPIPoolExecutor(10), URLS
),
),
]:
sys.stdout.write(f"{meth.ljust(11)}: ")
sys.stdout.flush()
start = time.time()
url_map = fn()
elapsed = time.time() - start
m, n = len(url_map), len(URLS)
sys.stdout.write(
f"{elapsed:5.2f} seconds ({m:2d} of {n:d} downloaded)\n",
)
sys.stdout.flush()
if __name__ == "__main__":
main()
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