def _acquire(self, path):
if self._lock and self._lock.acquired:
raise RuntimeError(
_("Attempting to lock {} when {} "
"is already locked.").format(path, self._lock))
self._lock = lockutils.InterProcessLock(path=path)
return self._lock.acquire()
def test_interprocess_lock(self):
lock_file = os.path.join(self.lock_dir, 'processlock')
pid = os.fork()
if pid:
# Make sure the child grabs the lock first
start = time.time()
while not os.path.exists(lock_file):
if time.time() - start > 5:
self.fail('Timed out waiting for child to grab lock')
time.sleep(0)
lock1 = lockutils.InterProcessLock('foo')
lock1.lockfile = open(lock_file, 'w')
# NOTE(bnemec): There is a brief window between when the lock file
# is created and when it actually becomes locked. If we happen to
# context switch in that window we may succeed in locking the
# file. Keep retrying until we either get the expected exception
# or timeout waiting.
while time.time() - start < 5:
try:
lock1.trylock()
lock1.unlock()
time.sleep(0)
except IOError:
# This is what we expect to happen
break
else:
self.fail('Never caught expected lock exception')
# We don't need to wait for the full sleep in the child here
os.kill(pid, signal.SIGKILL)
else:
try:
lock2 = lockutils.InterProcessLock('foo')
lock2.lockfile = open(lock_file, 'w')
have_lock = False
while not have_lock:
try:
lock2.trylock()
have_lock = True
except IOError:
pass
finally:
# NOTE(bnemec): This is racy, but I don't want to add any
# synchronization primitives that might mask a problem
# with the one we're trying to test here.
time.sleep(.5)
os._exit(0)
def get_process_lock(file):
if not os.access(file, os.W_OK):
msg = output_err(633, file=file)
raise exception.HBSDError(message=msg)
return lockutils.InterProcessLock(file)
def lockb(wait):
b = lockutils.InterProcessLock(os.path.join(tmpdir, 'b'))
with b:
wait.wait()
def locka(wait):
a = lockutils.InterProcessLock(os.path.join(tmpdir, 'a'))
with a:
wait.wait()
self.completed = True
