def lock(flow_class, process_pk):
for i in range(attempts):
with transaction.atomic():
try:
process = flow_class.process_class._default_manager.filter(pk=process_pk)
if not process.select_for_update(nowait=nowait).exists():
raise DatabaseError('Process not exists')
yield
break
except DatabaseError:
if i != attempts - 1:
sleep_time = (((i + 1) * random.random()) + 2 ** i) / 2.5
time.sleep(sleep_time)
else:
raise FlowLockFailed('Lock failed for {}'.format(flow_class))
def lock(flow_cls, process_pk):
key = 'django-viewflow-lock-{}/{}'.format(flow_cls._meta.namespace,
process_pk)
for i in range(attempts):
stored = cache.add(key, 1, expires)
if stored:
break
if i != attempts - 1:
sleep_time = (((i + 1) * random.random()) + 2**i) / 2.5
time.sleep(sleep_time)
else:
raise FlowLockFailed('Lock failed for {}'.format(flow_cls))
with transaction.atomic():
yield
cache.delete(key)
def lock(flow_class, process_pk):
key = 'django-viewflow-lock-{}/{}'.format(
flow_class._meta.flow_label, process_pk)
for i in range(self.attempts):
if self.cache.add(key, 1, self.expires):
break
if i != self.attempts - 1:
sleep_time = (((i + 1) * random.random()) + 2**i) / 2.5
time.sleep(sleep_time)
else:
raise FlowLockFailed('Lock failed for {}'.format(flow_class))
try:
with transaction.atomic():
yield
finally:
self.cache.delete(key)
def lock(flow_cls, process_pk):
key = 'django-viewflow-lock-{}/{}'.format(flow_cls._meta.namespace,
process_pk)
for i in range(attempts):
lock = cache.lock(key, timeout=expires)
stored = lock.acquire(blocking=False)
if stored:
break
if i != attempts - 1:
sleep_time = (((i + 1) * random.random()) + 2**i) / 2.5
time.sleep(sleep_time)
else:
raise FlowLockFailed('Lock failed for {}'.format(flow_cls))
try:
with transaction.atomic():
yield
finally:
lock.release()
def lock(flow_class, process_pk):
key = 'django-viewflow-lock-{}/{}'.format(flow_class._meta.flow_label, process_pk)
for i in range(attempts):
process = flow_class.process_class._default_manager.filter(pk=process_pk)
if process.exists():
stored = cache.add(key, 1, expires)
if stored:
break
if i != attempts - 1:
sleep_time = (((i + 1) * random.random()) + 2 ** i) / 2.5
time.sleep(sleep_time)
else:
raise FlowLockFailed('Lock failed for {}'.format(flow_class))
try:
with transaction.atomic():
yield
finally:
cache.delete(key)
def lock(flow_cls, process_pk):
assert transaction.get_autocommit(
) or transaction.commit.__module__ == 'django.test.testcases'
with transaction.atomic():
for i in range(attempts):
try:
flow_cls.process_cls._default_manager \
.filter(pk=process_pk) \
.select_for_update(nowait=nowait) \
.exists()
break
except DatabaseError:
if i != attempts - 1:
sleep_time = (((i + 1) * random.random()) + 2**i) / 2.5
time.sleep(sleep_time)
else:
raise FlowLockFailed(
'Lock failed for {}'.format(flow_cls))
yield
