暂停和恢复多进程 python 对象

Question

我有问题需要使用多处理创建 python 进程线程 任何暂停它的时间 - 然后再恢复它 - 问题是这个逻辑可以在多线程上执行。

我尝试使用 Event 但我是 python 多处理的新手。

这是我创建的代码，但暂停/恢复不起作用 - 请帮忙:)？

import multiprocessing

def control_process(process):
    """
    Receive a process object as an argument and provides the ability
    to pause and resume the process.
    """
    while True:
        command = input("Enter 'p' to pause, 'r' to resume, or 'q' to quit: ")
        print(command)
        if command == "p":
            process.set()
        elif command == "r":
            process.clear()
        elif command == "q":
            process.terminate()
            break
import time

def my_function():
    while True:
        print("Hello, world!")
        time.sleep(1)

if __name__ == "__main__":
    p = multiprocessing.Process(target=my_function)
    p.start()
    
    control_process(p)

输出应该是

Start thread 1 ....
puase thread 1 ....
start thread 2 ....
Thread 2 ......
Thread 2 ......
End Thread 2 ....
End thread 1 ...

Answer 1

你应该为此使用一个 multiprocessing.Event，基本上你会把一个传递给孩子和控制线程并让它

set

它恢复和

clear

它暂停执行如下。

import multiprocessing
import time

def control_process(process, pause_event):
    """
    Receive a process object as an argument and provides the ability
    to pause and resume the process.
    """
    while True:
        command = input("Enter 'p' to pause, 'r' to resume, or 'q' to quit: ")
        print(command)
        if command == "p":
            pause_event.clear()
        elif command == "r":
            pause_event.set()
        elif command == "q":
            process.terminate()
            break

def my_function(pause_event, event_started):
    event_started.set()  # signal parent that it has started execution
    while pause_event.wait():  # returns True if pause_event is set
        print("Hello, world!")
        time.sleep(1)
if __name__ == "__main__":
    pause_event = multiprocessing.Event()
    started_event = multiprocessing.Event()  # to know when the child started execution
    p = multiprocessing.Process(target=my_function, args=(pause_event, started_event))
    p.start()

    started_event.wait(timeout=5)  # to fix window's buggy terminal

    control_process(p, pause_event)

如果您在 Windows 上使用

started_event

，那么

input

的使用很重要，因为它会锁定整个终端，从而防止孩子在

input

功能结束之前产卵。

Answer 2

要使“p”（暂停）和“r”（恢复）工作，您可以使用 multiprocessing.Event

pause_event

而不是 process.

此外，无需再次打印命令，因为您可以在命令输入中看到它。

尝试以下代码：

import multiprocessing,time
    
def my_function(pause_event):
    while True:
        if not pause_event.is_set():
            print("Hello, world!")
        time.sleep(1)

if __name__ == "__main__":
    pause_event = multiprocessing.Event()
    pause_event.clear()
    p = multiprocessing.Process(target=my_function, args=(pause_event,))
    p.start()
    
    while True:
        command = input("Enter 'p' to pause, 'r' to resume, or 'q' to quit: ")
        if command == "p":
            pause_event.set()
        elif command == "r":
            pause_event.clear()
        elif command == "q":
            p.terminate()
            break

if __name__ == "__main__":
    p = multiprocessing.Process(target=my_function)
    p.start()
    
    control_process(p)

最后，如果你希望你的输出如你所愿，你应该为你的线程添加相应的打印。