在 Python 中维护一个可自动清理的线程列表

Question

我维护了一个 threads 列表，我想 线程完成后自动从列表中删除线程 。

我找到了这个方法：

import threading, time

def f(seconds, info):
    print('starting', seconds)
    time.sleep(seconds)
    print('finished', seconds)
    threads.remove(info['thread'])

def newaction(seconds):
    info = {}
    thread = threading.Thread(target=f, args=(seconds, info))
    info['thread'] = thread
    thread.start()
    threads.append(thread)

threads = []
newaction(1)
newaction(2)
for _ in range(10):
    time.sleep(0.3)
    print(threads)

有效：

starting 1
starting 2
[<Thread(Thread-1, started 1612)>, <Thread(Thread-2, started 712)>]
[<Thread(Thread-1, started 1612)>, <Thread(Thread-2, started 712)>]
[<Thread(Thread-1, started 1612)>, <Thread(Thread-2, started 712)>]
finished 1
[<Thread(Thread-2, started 712)>]
[<Thread(Thread-2, started 712)>]
[<Thread(Thread-2, started 712)>]
finished 2
[]
[]
[]
[]

但是必须通过一个命令 info 的事实有点麻烦。我使用它是因为显然我不能在 args...

中传递 thread

thread = threading.Thread(target=f, args=(seconds, thread))  
#                                                     ^ not created yet!

...当 Thread 对象尚未创建时！

在 Python 中是否有更自然的方法来维护可自动清理的线程列表？

Answer 1

import threading

def get_status_of_threads():
    current_threads = threading.enumerate()

    thread_data = []

    for item in current_threads:
        try:
            print(str(item.target))
        except AttributeError:
            print("item", str(item))
        thread_data.append({"thread_name": item.getName(), "status": int(item.is_alive()), "id": item.ident})
    return thread_data

上面的代码在Python2.7中测试过，如果你想持续监控线程，你可以在一个单独的线程中使用它，或者你可以将它暴露为一个API，所以您可以随时检查。这也将有助于减少资源浪费。

对于API，您可以使用json2html.convert({"thread_data":thread_data})功能以表格形式更美观地显示它。

Answer 2

你有 current_thread() 功能。

import threading, time

def f(seconds):
    print('starting', seconds)
    time.sleep(seconds)
    print('finished', seconds)
    threads.remove(threading.current_thread())

def newaction(seconds):
    thread = threading.Thread(target=f, args=(seconds,))
    thread.start()
    threads.append(thread)

threads = []
newaction(1)
newaction(2)
for _ in range(10):
    time.sleep(0.3)
    print(threads)

输出：

starting 1
starting 2
[<Thread(Thread-1, started 4588)>, <Thread(Thread-2, started 4388)>]
[<Thread(Thread-1, started 4588)>, <Thread(Thread-2, started 4388)>]
[<Thread(Thread-1, started 4588)>, <Thread(Thread-2, started 4388)>]
finished 1
[<Thread(Thread-2, started 4388)>]
[<Thread(Thread-2, started 4388)>]
[<Thread(Thread-2, started 4388)>]
finished 2
[]
[]
[]
[]

Answer 3

Thread 的子类化产生了一种具有自然语法和安全位置来保存线程列表的解决方案。您也不必在要在另一个线程中运行的每个函数的末尾包含删除线程的指令。只需使用子类。

import threading, time

class AutoRemovingThread(threading.Thread):
  threads = []
  def __init__(self, func, *args, **kwargs):
    super().__init__()
    self.threads.append(self)
    self.func = func
    self.args = args
    self.kwargs = kwargs
  def run(self):
    self.func(*self.args, **self.kwargs)
    self.threads.remove(self)

def f(seconds):
  print('starting', seconds)
  time.sleep(seconds)
  print('finished', seconds)

def newaction(seconds):
  AutoRemovingThread(f, seconds).start()

newaction(1)
newaction(2)
for _ in range(10):
  time.sleep(0.3)
  print(AutoRemovingThread.threads)

输出：

starting 1
starting 2
[<AutoRemovingThread(Thread-1, started 8436)>, <AutoRemovingThread(Thread-2, started 1072)>]
[<AutoRemovingThread(Thread-1, started 8436)>, <AutoRemovingThread(Thread-2, started 1072)>]
[<AutoRemovingThread(Thread-1, started 8436)>, <AutoRemovingThread(Thread-2, started 1072)>]
finished 1
[<AutoRemovingThread(Thread-2, started 1072)>]
[<AutoRemovingThread(Thread-2, started 1072)>]
[<AutoRemovingThread(Thread-2, started 1072)>]
finished 2
[]
[]
[]
[]

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