python3中async使用run_in_executor构建异步task及functools传参

日期 2023年05月30日 10:47

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python3中async使用run_in_executor构建异步task及functools传参

代码示例:

import asyncio
import functools
import threading
import time

import requests


def request_download_img(url, param1, param2):
    print("request_download_img:", time.time(), url, param1, param2)
    time.sleep(5)
    response = requests.get(url)
    # 图片保存到本地文件
    file_name = url.rsplit('_')[-1]
    with open(file_name, mode='wb') as file_object:
        file_object.write(response.content)


async def create_async_task(url, param1, param2):
    loop = asyncio.get_event_loop()
    # 使用run_in_executor将同步函数构建异步task
    future = loop.run_in_executor(None, functools.partial(
        request_download_img,
        url=url,
        param1=param1,
        param2=param2,
    ))
    # 避免 coroutine was never awaited
    await future


def run_sync():
    url_list = [
        'https://www3.autoimg.cn/newsdfs/g26/M02/35/A9/120x90_0_autohomecar__ChsEe12AXQ6AOOH_AAFocMs8nzU621.jpg',
        'https://www2.autoimg.cn/newsdfs/g30/M01/3C/E2/120x90_0_autohomecar__ChcCSV2BBICAUntfAADjJFd6800429.jpg',
        'https://www3.autoimg.cn/newsdfs/g26/M0B/3C/65/120x90_0_autohomecar__ChcCP12BFCmAIO83AAGq7vK0sGY193.jpg'
    ]
    task1 = create_async_task(url_list[0], param1="a", param2="b")
    task2 = create_async_task(url_list[0], param1="a", param2="b")
    task3 = create_async_task(url_list[0], param1="a", param2="b")
    tasks = [task1, task2, task3]
    # 执行多个异步任务
    loop = asyncio.get_event_loop()
    loop.run_until_complete(asyncio.wait(tasks))

    print("tasks", tasks)
    

if __name__ == '__main__':
    p1 = threading.Thread(target=run_sync, daemon=False)
    p1.run()

解决async 运行多线程时报错 RuntimeError: There is no current event loop in thread 'Thread-2'

# 多线程-非主线程-事件控制
new_loop = asyncio.new_event_loop()
asyncio.set_event_loop(new_loop)
loop = asyncio.get_event_loop()
loop.run_until_complete(asyncio.wait(tasks))
# new_event_loop 可以 close
loop.close()

参考:
https://www.cnblogs.com/cwp-bg/p/9590700.html
https://zhuanlan.zhihu.com/p/137057192
https://www.cnblogs.com/SunshineKimi/p/12053914.html