如何在另一个子进程完成时杀死正在运行的子进程(在多进程中)

Question

我遇到了一个多进程问题:

class PythonHelper(object):
    @staticmethod
    def run_in_parallel(*functions):
        processes=list()
        for function in functions:
            process=Process(target=function)
            process.start()
            processes.append(process)
        for process in processes:
            process.join()

我使用上面的静态方法来同时运行几个函数(将它们组合在一个进程中)。一切都很好，直到我遇到需要在'subprocess'之一被终止时强制进程终止。

例如:

from PythonHelper import PythonHelper as ph
from Recorder import Recorder
class Logger(object):
    def run_recorder_proc(self):
        rec=Recorder()
        rec.record_video()
    def run_printer_proc(self):
    #hypothetical function: execution takes a long time
        for i in range(9000000):
            print("number: {}".format(i))
    def run_logger(self):
        ph.run_in_parallel(self.run_printer_proc,self.run_recorder_proc)

self.run_printer_proc和self.run_recorder_proc是我的子进程。当其中一个子进程完成时，如何"杀死"剩余子进程?

---

编辑:完整源代码:

class PythonHelper(object):
    @staticmethod
    #with your fix
    def run_in_parallel(*functions):
        processes={}
        for function in functions:
            process=Process(target=function)
            process.start()
            processes[process.pid]=process
        # wait for any process to complete
        pid, status = os.waitpid(-1, 0)
        # one process terminated
        # join it
        processes[pid].join()
        del processes[pid]
        # terminate the rest
        for process in processes.values():
            process.terminate()
        for process in processes.values():
            process.join()

class Logger(object):
    def run_numbers_1(self):
        for i in range(900000):
            print("number: {}".format(i))
    def run_numbers_2(self):
        for i in range(100000):
            print("number: {}".format(i))
    def run_logger(self):
        ph.run_in_parallel(self.run_numbers_1,self.run_numbers_2)
if __name__=="__main__":
    logger=Logger()
    logger.run_logger()

根据上面的例子，我想强制终止run_numbers_1当run_numbers_2完成

Answer 1

您可以通过稍微更改run_in_parallel()来实现:

def run_in_parallel(*functions):
    processes={}
    for function in functions:
        process=Process(target=function)
        process.start()
        processes[process.pid]=process
    # wait for any process to complete
    pid, status = os.waitpid(-1, 0) 
    # one process terminated
    # join it
    processes[pid].join()
    del processes[pid]
    # terminate the rest
    for process in processes.itervalues():
        process.terminate()
    for process in processes.itervalues():
        process.join()

(更新)

基于您的完整代码，这里是一个工作示例。它使用Event对象，而不是容易出错的os.waitpid()，其他进程在完成时设置:

from multiprocessing import Process, Event
class MyProcess(Process):
    def __init__(self, event, *args, **kwargs):
        self.event = event
        Process.__init__(self, *args, **kwargs)
    def run(self):
        Process.run(self)
        self.event.set()
class PythonHelper(object):
    @staticmethod
    #with your fix
    def run_in_parallel(*functions):
        event = Event()
        processes=[]
        for function in functions:
            process=MyProcess(event, target=function)
            process.start()
            processes.append(process)
        # wait for any process to complete
        event.wait()
        # one process completed
        # terminate all child processes
        for process in processes:
            process.terminate()
        for process in processes:
            process.join()

class Logger(object):
    def run_numbers_1(self):
        for i in range(90000):
            print("1 number: {}".format(i))
    def run_numbers_2(self):
        for i in range(10000):
            print("2 number: {}".format(i))
    def run_logger(self):
        PythonHelper.run_in_parallel(self.run_numbers_1,self.run_numbers_2)
if __name__=="__main__":
    logger=Logger()
    logger.run_logger()