====== 04 Python 並列処理 ======

<code|parallel.py>
import time
from concurrent.futures import ThreadPoolExecutor
from logging import StreamHandler, Formatter, INFO, getLogger

def init_logger():
    handler = StreamHandler()
    handler.setLevel(INFO)
    handler.setFormatter(Formatter("[%(asctime)s] [%(threadName)s] %(message)s"))
    logger = getLogger()
    logger.addHandler(handler)
    logger.setLevel(INFO)
    
def task(v):
    getLogger().info("%s start", v)
    time.sleep(1.0)
    getLogger().info("%s end", v)
    
def main():
    init_logger()
    getLogger().info("main start")
    with ThreadPoolExecutor(max_workers=2, thread_name_prefix="thread") as executor:
        for i in range(5):
            executor.submit(task, i)
        getLogger().info("submit end")
    getLogger().info("main end")


if __name__ == "__main__":
    main()
</code>

===== 実行結果 =====

<code>
# python3.6 parallel.py
[2019-08-09 11:23:41,298] [MainThread] main start
[2019-08-09 11:23:41,300] [thread_0] 0 start
[2019-08-09 11:23:41,301] [thread_1] 1 start
[2019-08-09 11:23:41,301] [MainThread] submit end
[2019-08-09 11:23:42,302] [thread_0] 0 end
[2019-08-09 11:23:42,302] [thread_0] 2 start
[2019-08-09 11:23:42,302] [thread_1] 1 end
[2019-08-09 11:23:42,302] [thread_1] 3 start
[2019-08-09 11:23:43,303] [thread_0] 2 end
[2019-08-09 11:23:43,304] [thread_0] 4 start
[2019-08-09 11:23:43,304] [thread_1] 3 end
[2019-08-09 11:23:44,305] [thread_0] 4 end
[2019-08-09 11:23:44,305] [MainThread] main end
</code>

{{tag>python}}