python子流程.Popenfutex中的方块

Question

我正在尝试实现一些基本的调度来产生最大n过程。波本然后等待它们执行。为此我做了：

CHECKING_INTERVAL = 10

class StandAloneClient(object):
    """
    Instead of communicating with a backend cluster, fire locally a new thread.
    """
    max_thread_nr = 4
    thread_pool = []
    pending_operations = Queue.Queue(0)

    class OperationExecutor(threading.Thread):

        def run(self):
            """
            Get the required data from the operation queue and launch the operation.
            """
            while True:
                launch_data = StandAloneClient.pending_operations.get()
                if launch_data != None:
                    operation_id = launch_data[0]
                    user_name_label = launch_data[1]
                    LOGGER.debug("Launching operation " + str(operation_id) + " with name " + str(user_name_label))
                    ## Create a new process for the new launched operation
                    oper = ['python', '-m', 'processRunner', str(operation_id), user_name_label]
                    launched_process = Popen(oper, stdout=PIPE, stdin=PIPE, stderr=PIPE)
#                    launched_process.wait()
#                    while launched_process.poll() is None:
#                        sleep(CHECKING_INTERVAL)
#                        LOGGER.debug("Operation id=%s is still running. Going to sleep for %s seconds."%(operation_id,
#                                                                                                         CHECKING_INTERVAL))
                    LOGGER.debug("===========================================================")
                    LOGGER.debug("Finished operation %s succesfully."%(operation_id,))


    def __init__(self):
        """
        If there are still empty spots create a new executor thread.
        """
        for _ in xrange(self.max_thread_nr - len(self.thread_pool)):
            new_executor = StandAloneClient.OperationExecutor()
            self.thread_pool.append(new_executor)
            new_executor.start()

    @staticmethod
    def execute(operation_id, user_name_label="Unknown"):
        """Start asynchronous operation locally"""
        StandAloneClient.pending_operations.put((operation_id, user_name_label))

我通过以下方式向队列添加操作：

^{pr2}$

现在我已经评论了我认为可能因为某种原因而阻塞线程的部分。但即便如此，似乎没有一个孩子的出生永远结束。执行直到结束，我检查了日志，processRunner.py完成了它需要做的所有事情，直到结束，但是如果我执行ps -el|grep python，我仍然可以看到生成的所有进程：

    0 S  1000   755     1  5  80   0 - 548314 poll_s pts/0   00:00:13 python
0 S  1000  1198   755  4  80   0 - 280172 futex_ pts/0   00:00:09 python
0 S  1000  1201   755  4  80   0 - 280176 futex_ pts/0   00:00:09 python
0 S  1000  1206   755  4  80   0 - 280230 futex_ pts/0   00:00:09 python
0 S  1000  1215   755  4  80   0 - 280198 futex_ pts/0   00:00:09 python
0 S  1000  1216   755  4  80   0 - 281669 futex_ pts/0   00:00:09 python
0 S  1000  1221   755  4  80   0 - 280201 futex_ pts/0   00:00:09 python
0 S  1000  1231   755  4  80   0 - 281668 futex_ pts/0   00:00:09 python
0 S  1000  1240   755  4  80   0 - 280229 futex_ pts/0   00:00:09 python
0 S  1000  1257   755  4  80   0 - 280201 futex_ pts/0   00:00:09 python

我在一台fedora16机器上使用python2.7.2来尝试这个。有什么建议>

谨致问候， 博格丹

Answer 1

你的线程不是守护进程。它们在主线程退出后继续生存。它们永远被阻止在pending_operations.get()。在