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 get(self):
"""
Get or create a database connection for temporary use.
The connection is automatically closed when the context exits.
"""
try:
alias = self.connections.get(block=False)
except Empty:
alias = self._new_connection()
try:
yield alias
finally:
with connection_state.force(None):
connections[alias].close()
self.connections.put(alias)
def get(self):
"""
Get or create a database connection for temporary use.
The connection is automatically closed when the context exits.
"""
try:
alias = self.connections.get(block=False)
except Empty:
alias = self._new_connection()
try:
yield alias
finally:
with connection_state.force(None):
connections[alias].close()
self.connections.put(alias)
