英文:
Attempting to run threads concurrently inside while loop in Python 3.11
问题
我正在努力理解Python 3.11中的线程处理，并试图弄清楚为什么当我在execute_subtasks中加入time.sleep(120)时，下一个线程没有被处理，代码似乎是顺序运行而不是并发运行。
我需要在for循环外面启动线程，还是需要移动join的位置？
英文:
I am trying to get my head around threading in Python 3.11 and I am trying to work out why when I put a time.sleep(120) inside execute_subtasks that the next thread is not processed and the code appears to run sequentially instead of concurrently.
Do I need to start the thread outside of the for loop or do I need to move the location of the join?
from threading import Thread, Event, active_count, current_thread
threads = list()
while True:
try:
# ignore the main thread
if active_count() > 1:
for index, thread in enumerate(threads):
thread.join()
for message in queue.get_messages(4):
if active_count() >= config.maxthreads + 1:
# Thread pool is about to overflow. Skipping.
continue
x = threading.Thread(
target=message.get_task().execute_subtasks,
daemon=True,
args=[message.get_context()]
)
threads.append(x)
x.start()
except Exception:
# Exception in dispatch loop
答案1
得分: 1
不需要在加入已停止的线程时使用 active_count()，因为你唯一关心的线程都在你的 threads 列表中。
实现这个函数...
def remove_dead_threads(_list):
for thread in [t for t in _list if not t.is_alive()]:
thread.join()
_list.remove(thread)
然后，在 try: 后的第一行代码中执行...
remove_dead_threads(threads)
这将通过加入那些不再存活的线程来清理你的 threads 列表。
你还可以考虑使用 ThreadPoolExecutor 来简化线程池管理。
英文:
You do not need to use active_count() when joining dead threads because the only threads you're interested in are in your threads list.
Implement this function...
def remove_dead_threads(_list):
for thread in [t for t in _list if not t.is_alive()]:
thread.join()
_list.remove(thread)
Then, as the first line of code after try: do...
remove_dead_threads(threads)
This will clean up your threads list by joining those that are no longer alive.
You could also consider using a ThreadPoolExecutor to make pool management easier
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