线程可以在Python中创建子线程吗？

Question

我熟悉在python中创建线程的语法.

from threading import Thread
from queue import Queue

task_queue = Queue(maxsize=0)    

num_threads=10
for i in range(num_threads):
    thread = Thread(target=work, args=(task_queue,))
    thread.start()

task_queue.join()

我的问题是天气可以在其他线程中打开新线程,如下所示:

def work(task_queue):
    task = task_queue.get()

    subtasks = task.get_sub_tasks()

    for subtask in subtasks:
        thread = Thread(target=sub_work, args(subtask,))
        thread.start()

所以

1. 这个结构好吗？或者这样做是不是很麻烦？

2. 如果这没关系,子线程进程是否从属于生成它的线程,或者它们是否是父python进程的子进程？如果创建子线程的线程"死"并出现错误,那么子线程会发生什么？

我意识到python线程受解释器全局锁定,但我的应用程序涉及访问服务器,因此多线程是为了避免序列化连接需要太长时间.

Answer 1

所以关于你的问题:

• Q1:从线程启动"subthreads"不是问题
• Q2:这实际上是一个有趣的问题,我的直觉会说"不",但获得一个证据对我来说听起来更好

所以我创建了一个快速测试,如下所示(我会使用一个要点,但我不能从我所在的地方访问这些东西):

from threading import Thread
import time

def sub_worker(id):
    print("SubWorker started from thread", id)
    while True:
        print("Subworking...")
        time.sleep(5)
def worker(id):
    print("Worker started from thread", id)
    count = 1
    while count < 5:
        print("Working...")
        tmp_thread = Thread(target=sub_worker, args=[count])
        tmp_thread.start()
        count +=1
        time.sleep(1)
    raise EnvironmentError("Tired of working")

main = Thread(target=worker, args=[0])

main.start()

这给了我们输出(正如预期的那样,父线程中的错误不会阻止"子"):

Worker started from thread 0
Working...
SubWorker started from thread 1
Subworking...
Working...
SubWorker started from thread 2
Subworking...
Working...
SubWorker started from thread 3
Subworking...
Working...
SubWorker started from thread 4
Subworking...
Exception in thread Thread-1:
Traceback (most recent call last):
  File "C:\Temp\tt\Tools\Anaconda3.4.3.1\lib\threading.py", line 916, in _bootstrap_inner
    self.run()
  File "C:\Temp\tt\Tools\Anaconda3.4.3.1\lib\threading.py", line 864, in run
    self._target(*self._args, **self._kwargs)
  File "C:/Temp/tt/Tools/PyCharmWorkspace/xml_parse/test.py", line 18, in worker
    raise EnvironmentError("Tired of working")
OSError: Tired of working

Subworking...
Subworking...
Subworking...
Subworking...
Subworking...
Subworking...
Subworking...

我认为htop显示这种层次结构可能是由于Linux内核将线程视为进程.因为调用fork就可以显示这个层次结构.有了线程的概念,我不相信层次结构如此有意义,因为它们中的每一个都将共享相同的资源(内存,文件描述符......等)