core/homeassistant/util/thread.py

67 lines
2.0 KiB
Python

"""Threading util helpers."""
import ctypes
import inspect
import logging
import threading
from typing import Any
THREADING_SHUTDOWN_TIMEOUT = 10
_LOGGER = logging.getLogger(__name__)
def deadlock_safe_shutdown() -> None:
"""Shutdown that will not deadlock."""
# threading._shutdown can deadlock forever
# see https://github.com/justengel/continuous_threading#shutdown-update
# for additional detail
remaining_threads = [
thread
for thread in threading.enumerate()
if thread is not threading.main_thread()
and not thread.daemon
and thread.is_alive()
]
if not remaining_threads:
return
timeout_per_thread = THREADING_SHUTDOWN_TIMEOUT / len(remaining_threads)
for thread in remaining_threads:
try:
thread.join(timeout_per_thread)
except Exception as err: # noqa: BLE001
_LOGGER.warning("Failed to join thread: %s", err)
def async_raise(tid: int, exctype: Any) -> None:
"""Raise an exception in the threads with id tid."""
if not inspect.isclass(exctype):
raise TypeError("Only types can be raised (not instances)")
c_tid = ctypes.c_ulong(tid) # changed in python 3.7+
res = ctypes.pythonapi.PyThreadState_SetAsyncExc(c_tid, ctypes.py_object(exctype))
if res == 1:
return
# "if it returns a number greater than one, you're in trouble,
# and you should call it again with exc=NULL to revert the effect"
ctypes.pythonapi.PyThreadState_SetAsyncExc(c_tid, None)
raise SystemError("PyThreadState_SetAsyncExc failed")
class ThreadWithException(threading.Thread):
"""A thread class that supports raising exception in the thread from another thread.
Based on
https://stackoverflow.com/questions/323972/is-there-any-way-to-kill-a-thread/49877671
"""
def raise_exc(self, exctype: Any) -> None:
"""Raise the given exception type in the context of this thread."""
assert self.ident
async_raise(self.ident, exctype)