Some useful, well-tested extensions of threading.Thread. Tested for Python 2.7.
Thread with internal stop event. To properly work, the run method or target function MUST check for changes in the stop threading.Event.
- If using
runclass method, periodically check if <threading.Event>self._stopis set:self._stop.is_set() - If using
targetfunction keyword argument, the stopthreading.Eventwill be passed in as the last positional argument.
class DoSomethingThread(StoppableThread):
def run(self):
# self._stop is an instance of <threading.Event>
while not self._stop.is_set():
do_something()
# use `_stop.wait` in place of `time.sleep` b/c wait is interrupted
# by the event being set and will immediately exit
self._stop.wait(10)
dt = DoSomethingThread()
dt.start()
assert(dt.is_alive() is True)
assert(dt.stopped is False) # stopped is a property
dt.stop() # sets the stop event in the thread
dt.join() # wait until thread returns
assert(dt.is_alive() is False)
assert(dt.stopped is True)
def infinite_running_target(x, stop_event, y=None):
# x & y are examples
while not stop_event.is_set():
do_something()
# use `stop_event.wait` in place of `time.sleep` b/c wait is interrupted by
# stop being set and will immediately exit the wait
stop_event.wait(1)
st = StoppableThread(target=infinite_running_target, args=(1,), kwargs={"y": 2})
st.start()
assert(st.is_alive() is True)
assert(st.stopped is False)
st.stop()
st.join()
assert(st.is_alive() is False)
assert(st.stopped is True)
Thread that propogates exceptions raised in the thread to the main context on join. To properly work using the class method run, implement run_with_exception method instead.
class RaiseThread(ExceptionThread):
def run_with_exception(self):
raise ValueError('eep!')
rt = RaiseThread()
rt.start()
rt.join() # ValueError: 'eep!', with complete stack trace
def raises_exception_target(x, y=None):
# x & y are examples
raise ValueError('eep!')
et = Thread(target=raises_exception_target, args=(1,), kwargs={"y": 2})
et.start()
et.join() # ValueError: 'eep!', with complete stack trace
assert(et.is_alive() is False)
Thread that is both stoppable AND propogates exceptions to the main context on join. To properly work using the class method run, implement run_with_exception method instead.
See above examples.
pip install https://github.com/fraserharris/threading-extensions/archive/master.zip
Happy Threading!