def test_no_double_writers(self):
lock = fasteners.ReaderWriterLock()
watch = _utils.StopWatch(duration=5)
watch.start()
dups = collections.deque()
active = collections.deque()
def acquire_check(me):
with lock.write_lock():
if len(active) >= 1:
dups.append(me)
dups.extend(active)
active.append(me)
try:
time.sleep(random.random() / 100)
finally:
active.remove(me)
def run():
me = threading.current_thread()
while not watch.expired():
acquire_check(me)
threads = []
for i in range(0, self.THREAD_COUNT):
t = _daemon_thread(run)
threads.append(t)
t.start()
while threads:
t = threads.pop()
t.join()
self.assertEqual([], list(dups))
self.assertEqual([], list(active))
def _acquire(self,
blocking=True,
delay=DELAY_INCREMENT,
max_delay=MAX_DELAY,
timeout=None,
exclusive=True):
if delay < 0:
raise ValueError("Delay must be greater than or equal to zero")
if timeout is not None and timeout < 0:
raise ValueError("Timeout must be greater than or equal to zero")
if delay >= max_delay:
max_delay = delay
self._do_open()
watch = _utils.StopWatch(duration=timeout)
r = _utils.Retry(delay,
max_delay,
sleep_func=self.sleep_func,
watch=watch)
with watch:
gotten = r(self._try_acquire, blocking, watch, exclusive)
if not gotten:
return False
else:
self.logger.log(
_utils.BLATHER,
"Acquired file lock `%s` after waiting %0.3fs [%s"
" attempts were required]", self.path, watch.elapsed(),
r.attempts)
return True
def acquire(self,
blocking=True,
delay=DELAY_INCREMENT,
max_delay=MAX_DELAY,
timeout=None):
"""Attempt to acquire the given lock.
:param blocking: whether to wait forever to try to acquire the lock
:type blocking: bool
:param delay: when blocking this is the delay time in seconds that
will be added after each failed acquisition
:type delay: int/float
:param max_delay: the maximum delay to have (this limits the
accumulated delay(s) added after each failed
acquisition)
:type max_delay: int/float
:param timeout: an optional timeout (limits how long blocking
will occur for)
:type timeout: int/float
:returns: whether or not the acquisition succeeded
:rtype: bool
"""
if delay < 0:
raise ValueError("Delay must be greater than or equal to zero")
if timeout is not None and timeout < 0:
raise ValueError("Timeout must be greater than or equal to zero")
if delay >= max_delay:
max_delay = delay
try:
self._do_open()
watch = _utils.StopWatch(duration=timeout)
r = _utils.Retry(delay,
max_delay,
sleep_func=self.sleep_func,
watch=watch)
with watch:
gotten = r(self._try_acquire, blocking, watch)
if not gotten:
self.acquired = False
return False
else:
self.acquired = True
self.logger.log(
_utils.BLATHER,
"Acquired file lock `%s` after waiting %0.3fs [%s"
" attempts were required]", self.path, watch.elapsed(),
r.attempts)
return True
finally:
if not self.acquired:
self._do_close()
def test_no_concurrent_readers_writers(self):
lock = fasteners.ReaderWriterLock()
watch = _utils.StopWatch(duration=5)
watch.start()
dups = collections.deque()
active = collections.deque()
def acquire_check(me, reader):
if reader:
lock_func = lock.read_lock
else:
lock_func = lock.write_lock
with lock_func():
if not reader:
# There should be no-one else currently active, if there
# is ensure we capture them so that we can later blow-up
# the test.
if len(active) >= 1:
dups.append(me)
dups.extend(active)
active.append(me)
try:
time.sleep(random.random() / 100)
finally:
active.remove(me)
def run():
me = threading.current_thread()
while not watch.expired():
acquire_check(me, random.choice([True, False]))
threads = []
for i in range(0, self.THREAD_COUNT):
t = _daemon_thread(run)
threads.append(t)
t.start()
while threads:
t = threads.pop()
t.join()
self.assertEqual([], list(dups))
self.assertEqual([], list(active))