mirror of https://github.com/zulip/zulip.git
97 lines
3.2 KiB
Python
97 lines
3.2 KiB
Python
import ctypes
|
|
import logging
|
|
import sys
|
|
import threading
|
|
import time
|
|
from types import TracebackType
|
|
from typing import Callable, Optional, Tuple, Type, TypeVar
|
|
|
|
# Based on https://code.activestate.com/recipes/483752/
|
|
|
|
|
|
class TimeoutExpired(Exception):
|
|
"""Exception raised when a function times out."""
|
|
|
|
def __str__(self) -> str:
|
|
return "Function call timed out."
|
|
|
|
|
|
ResultT = TypeVar("ResultT")
|
|
|
|
|
|
def timeout(timeout: float, func: Callable[[], ResultT]) -> ResultT:
|
|
"""Call the function in a separate thread.
|
|
Return its return value, or raise an exception,
|
|
within approximately 'timeout' seconds.
|
|
|
|
The function may receive a TimeoutExpired exception
|
|
anywhere in its code, which could have arbitrary
|
|
unsafe effects (resources not released, etc.).
|
|
It might also fail to receive the exception and
|
|
keep running in the background even though
|
|
timeout() has returned.
|
|
|
|
This may also fail to interrupt functions which are
|
|
stuck in a long-running primitive interpreter
|
|
operation."""
|
|
|
|
class TimeoutThread(threading.Thread):
|
|
def __init__(self) -> None:
|
|
threading.Thread.__init__(self)
|
|
self.result: Optional[ResultT] = None
|
|
self.exc_info: Tuple[
|
|
Optional[Type[BaseException]],
|
|
Optional[BaseException],
|
|
Optional[TracebackType],
|
|
] = (None, None, None)
|
|
|
|
# Don't block the whole program from exiting
|
|
# if this is the only thread left.
|
|
self.daemon = True
|
|
|
|
def run(self) -> None:
|
|
try:
|
|
self.result = func()
|
|
except BaseException:
|
|
self.exc_info = sys.exc_info()
|
|
|
|
def raise_async_timeout(self) -> None:
|
|
# This function is called from another thread; we attempt
|
|
# to raise a TimeoutExpired in _this_ thread.
|
|
assert self.ident is not None
|
|
ctypes.pythonapi.PyThreadState_SetAsyncExc(
|
|
ctypes.c_long(self.ident),
|
|
ctypes.py_object(TimeoutExpired),
|
|
)
|
|
|
|
thread = TimeoutThread()
|
|
thread.start()
|
|
thread.join(timeout)
|
|
|
|
if thread.is_alive():
|
|
# We need to retry, because an async exception received while
|
|
# the thread is in a system call is simply ignored.
|
|
for i in range(10):
|
|
thread.raise_async_timeout()
|
|
time.sleep(0.1)
|
|
if not thread.is_alive():
|
|
break
|
|
if thread.exc_info[1] is not None:
|
|
# Re-raise the exception we sent, if possible, so the
|
|
# stacktrace originates in the slow code
|
|
raise thread.exc_info[1].with_traceback(thread.exc_info[2])
|
|
# If we don't have that for some reason (e.g. we failed to
|
|
# kill it), just raise from here; the thread _may still be
|
|
# running_ because it failed to see any of our exceptions, and
|
|
# we just ignore it.
|
|
if thread.is_alive():
|
|
logging.warning("Failed to time out backend thread")
|
|
raise TimeoutExpired
|
|
|
|
if thread.exc_info[1] is not None:
|
|
# Died with some other exception; re-raise it
|
|
raise thread.exc_info[1].with_traceback(thread.exc_info[2])
|
|
|
|
assert thread.result is not None
|
|
return thread.result
|