def create_lock_manager(self):
"""
Create a new LockManager. Tries to create a Redis LockManager, but falls
back to python's internal threading lock implementation.
Exits if distributing poller is enabled and a Redis LockManager cannot be created.
:return: Instance of LockManager
"""
try:
return LibreNMS.RedisLock(
namespace='librenms.lock',
host=self.config.redis_host,
port=self.config.redis_port,
db=self.config.redis_db,
password=self.config.redis_pass,
unix_socket_path=self.config.redis_socket,
sentinel=self.config.redis_sentinel,
sentinel_service=self.config.redis_sentinel_service,
socket_timeout=self.config.redis_timeout)
except ImportError:
if self.config.distributed:
critical(
"ERROR: Redis connection required for distributed polling")
critical(
"Please install redis-py, either through your os software repository or from PyPI"
)
self.exit(2)
except Exception as e:
if self.config.distributed:
critical(
"ERROR: Redis connection required for distributed polling")
critical("Could not connect to Redis. {}".format(e))
self.exit(2)
return LibreNMS.ThreadingLock()
def test_redis_lock(self):
if 'redis' not in sys.modules:
self.assertTrue(True, 'Skipped Redis tests')
else:
rc = redis.Redis()
rc.delete('lock:redis.lock') # make sure no previous data exists
lm = LibreNMS.RedisLock(namespace='lock')
thread = threading.Thread(target=self.lock_thread,
args=(lm, 'redis.lock', 2, 1))
thread.daemon = True
thread.start()
sleep(0.05)
self.assertFalse(lm.lock('redis.lock', 'main_thread', 1),
"Acquired lock when it is held by thread")
self.assertFalse(lm.unlock('redis.lock', 'main_thread'),
"Unlocked lock main doesn't own")
sleep(1.1)
self.assertTrue(
lm.lock('redis.lock', 'main_thread', 1),
"Could not acquire lock previously held by thread")
self.assertFalse(lm.lock('redis.lock', 'main_thread', 1),
"Relocked an existing lock")
self.assertTrue(lm.lock('redis.lock', 'main_thread', 1, True),
"Could not re-lock a lock main owns")
self.assertTrue(lm.unlock('redis.lock', 'main_thread'),
"Could not unlock lock main holds")
self.assertFalse(lm.unlock('redis.lock', 'main_thread'),
"Unlocked an unlocked lock?")
