def cluster_lock_steal(cluster_id, action_id):
with session_for_write() as session:
lock = session.query(models.ClusterLock).get(cluster_id)
if lock is not None:
lock.action_ids = [action_id]
lock.semaphore = -1
lock.save(session)
else:
lock = models.ClusterLock(cluster_id=cluster_id,
action_ids=[action_id],
semaphore=-1)
session.add(lock)
return lock.action_ids
def cluster_lock_acquire(cluster_id, action_id, scope):
'''Acquire lock on a cluster.
:param cluster_id: ID of the cluster.
:param action_id: ID of the action that attempts to lock the cluster.
:param scope: +1 means a node-level operation lock; -1 indicates
a cluster-level lock.
:return: A list of action IDs that currently works on the cluster.
'''
with session_for_write() as session:
lock = session.query(models.ClusterLock).get(cluster_id)
if lock is not None:
if scope == 1 and lock.semaphore > 0:
if action_id not in lock.action_ids:
lock.action_ids.append(six.text_type(action_id))
lock.semaphore += 1
lock.save(session)
else:
lock = models.ClusterLock(cluster_id=cluster_id,
action_ids=[six.text_type(action_id)],
semaphore=scope)
session.add(lock)
return lock.action_ids