Python concurrent 包

最新推荐文章于 2025-04-19 10:26:08 发布

Lee木木

最新推荐文章于 2025-04-19 10:26:08 发布

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分类专栏： Python 文章标签： python

本文链接：https://blog.youkuaiyun.com/weixin_44983653/article/details/124336080

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本文介绍了Python concurrent包，重点讲解了其提供的高级异步可执行接口，包括线程池和进程池的Executor，以及对上下文管理的支持。

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1、`concurrent.futures`

异步并行任务编程模块，提供一个高级的异步可执行的便利接口。

提供了两个池执行器：

ThreadPoolExecutor 异步调用的线程池的Executor
ProcessPoolExecutor 异步调用的进程池的Executor

2、`ThreadPoolExecutor`

ThreadPoolExecutor(max_workers=None)
# 池中至多创建max-workers个线程的池来同时异步执行，返回Executor实例

submit(*args, **kwargs)
# 提交执行的函数及其参数，返回Future类的实例

shutdown(wait=True)
# 清理池

在这里插入图片描述

# concurrent.futures
# ThreadPoolExecutor

from concurrent.futures import ThreadPoolExecutor
import time
import logging
import threading


FORMAT = "%(asctime)s %(threadName)22s %(thread)8d %(message)s"
logging.basicConfig(level=logging.INFO, format=FORMAT)

def worker(n):
    logging.info('enter thread ~~~~~~~~~~~~~~')
    time.sleep(n)
    logging.info('finished ~~~~~~~~~~~~')
    return n


executor = ThreadPoolExecutor(max_workers=3)

fs = []
for i in range(6):
    future = executor.submit(worker, i)  # 异步，非阻塞，执行完毕后立马执行下一条命令
    logging.info(future)
    fs.append(future)
# logging.info('-' * 55)
# for i in range(3):
#     future = executor.submit(worker, 5)  # 异步，非阻塞，执行完毕后立马执行下一条命令
#     logging.info(future)

# logging.info('=' * 55)
# executor.shutdown()
# logging.info('*' * 55)
while True:
    flag = True
    for f in fs:
        logging.info(f.done())
        flag = flag and f.done()

    if flag:
        executor.shutdown()
        logging.info(threading.enumerate())
        break

    # if threading.active_count() == 1:
    #     logging.info(threading.enumerate())
    #     logging.info(future)
    #     break
    time.sleep(1)
    logging.info(threading.enumerate())

for f in fs:
    logging.info(f.result())

2022-04-21 16:01:17,590 ThreadPoolExecutor-0_0     5212 enter thread ~~~~~~~~~~~~~~
2022-04-21 16:01:17,590             MainThread     7416 <Future at 0x1fb22ca8730 state=running>
2022-04-21 16:01:17,590 ThreadPoolExecutor-0_0     5212 finished ~~~~~~~~~~~~
2022-04-21 16:01:17,590 ThreadPoolExecutor-0_0     5212 enter thread ~~~~~~~~~~~~~~
2022-04-21 16:01:17,590             MainThread     7416 <Future at 0x1fb22ca8c70 state=running>
2022-04-21 16:01:17,590             MainThread     7416 <Future at 0x1fb22ca8fa0 state=pending>
2022-04-21 16:01:17,591 ThreadPoolExecutor-0_1    31892 enter thread ~~~~~~~~~~~~~~
2022-04-21 16:01:17,591 ThreadPoolExecutor-0_2    49012 enter thread ~~~~~~~~~~~~~~
2022-04-21 16:01:17,591             MainThread     7416 <Future at 0x1fb22cb6040 state=running>
2022-04-21 16:01:17,591             MainThread     7416 <Future at 0x1fb22cb6400 state=pending>
2022-04-21 16:01:17,591             MainThread     7416 <Future at 0x1fb22cb64f0 state=pending>
2022-04-21 16:01:17,591             MainThread     7416 True
2022-04-21 16:01:17,591             MainThread     7416 False
2022-04-21 16:01:17,591             MainThread     7416 False
2022-04-21 16:01:17,591             MainThread     7416 False
2022-04-21 16:01:17,591             MainThread     7416 False
2022-04-21 16:01:17,591             MainThread     7416 False
2022-04-21 16:01:18,593 ThreadPoolExecutor-0_0     5212 finished ~~~~~~~~~~~~
2022-04-21 16:01:18,593             MainThread     7416 [<_MainThread(MainThread, started 7416)>, <Thread(ThreadPoolExecutor-0_0, started daemon 5212)>, <Thread(ThreadPoolExecutor-0_1, started daemon 31892)>, <Thread(ThreadPoolExecutor-0_2, started daemon 49012)>]
2022-04-21 16:01:18,593 ThreadPoolExecutor-0_0     5212 enter thread ~~~~~~~~~~~~~~
2022-04-21 16:01:18,593             MainThread     7416 True
2022-04-21 16:01:18,594             MainThread