def grab_db_lock(lock_name, wait):
"""
Grab a lock using a new, temporary connection. Yields a "success"
boolean indicating whether the lock was successfully acquired or not.
This context manager ensures that multidb does not override the
connection when accessing the Lock model and its transaction. The
code that runs within this context should NOT be affected - it must
run as usual, with normal multidb functionality intact.
"""
with connections.get() as using:
try:
with connection_state.force(None):
transaction.enter_transaction_management(using=using)
transaction.managed(True, using=using)
lock = Lock.grab(lock_name, wait=wait, using=using)
success = bool(lock)
try:
yield success
finally:
if success:
with connection_state.force(None):
lock.release(using=using)
transaction.commit(using=using)
finally:
with connection_state.force(None):
transaction.leave_transaction_management(using=using)
def grab_db_lock(lock_name, wait):
"""
Grab a lock using the current database connection. Yields a "success"
boolean indicating whether the lock was successfully acquired or not.
WARNING: There may be issues if the code being wrapped by this context has
custom transaction management. The multidb context solves this problem.
"""
lock = Lock.grab(lock_name, wait=wait, using=using)
success = bool(lock)
try:
yield success
finally:
if success:
lock.release(using=using)
def _grab_lock(self, lock_name):
with self.get_connection() as using:
with no_multidb():
lock = Lock.grab(lock_name, wait=self.wait, using=using)
success = bool(lock)
yield success
def _grab_lock(self, lock_name):
with self.get_connection() as using:
with no_multidb():
lock = Lock.grab(lock_name, wait=self.wait, using=using)
success = bool(lock)
yield success
