def start(self):
"""Starts the cache.
The cache is not started automatically. You must call this method.
After a cache started, all changes of subtree will be synchronized
from the ZooKeeper server. Events will be fired for those activity.
See also :meth:`~TreeCache.listen`.
.. note::
This method is not thread safe.
"""
if self._state == self.STATE_LATENT:
self._state = self.STATE_STARTED
elif self._state == self.STATE_CLOSED:
raise KazooException('already closed')
else:
raise KazooException('already started')
self._client.add_listener(self._session_watcher)
self._client.ensure_path(self._root._path)
if self._client.connected:
self._root.on_created()
def test_announcer_under_abnormal_circumstances():
mock_serverset = create_autospec(spec=ServerSet, instance=True)
mock_serverset.join = MagicMock()
mock_serverset.join.side_effect = [
KazooException('Whoops the ensemble is down!'),
'member0001',
]
mock_serverset.cancel = MagicMock()
endpoint = Endpoint('localhost', 12345)
clock = ThreadedClock(31337.0)
announcer = Announcer(mock_serverset,
endpoint,
clock=clock,
exception_wait=Amount(2, Time.SECONDS))
announcer.start()
try:
clock.tick(1.0)
assert announcer.disconnected_time() == 1.0
clock.tick(2.0)
assert announcer.disconnected_time() == 0.0, (
'Announcer should recover after an exception thrown internally.')
assert announcer._membership == 'member0001'
finally:
announcer.stop()
def joined_side_effect(*args, **kw):
# 'global' does not work within python nested functions, so we cannot use a
# counter here, so instead we do append/len (see PEP-3104)
operations.append(1)
if len(operations) == 1 or len(operations) == 3:
joined.set()
return 'membership %d' % len(operations)
else:
raise KazooException('Failed to reconnect')
def start(self):
"""Starts the cache.
The cache is not started automatically. You must call this method.
After a cache started, all changes of subtree will be synchronized
from the ZooKeeper server. Events will be fired for those activity.
Don't forget to call :meth:`close` if a tree was started and you don't
need it anymore, or you will leak the memory of cached nodes, even if
you have released all references to the :class:`TreeCache` instance.
Because there are so many callbacks that have been registered to the
Kazoo client.
See also :meth:`~TreeCache.listen`.
.. note::
This method is not thread safe.
"""
if self._state == self.STATE_LATENT:
self._state = self.STATE_STARTED
elif self._state == self.STATE_CLOSED:
raise KazooException('already closed')
else:
raise KazooException('already started')
self._task_thread = self._client.handler.spawn(self._do_background)
self._client.add_listener(self._session_watcher)
self._client.ensure_path(self._root._path)
if self._client.connected:
# The on_created and other on_* methods must not be invoked outside
# the background task. This is the key to keep concurrency safe
# without lock.
self._in_background(self._root.on_created)
def __call__(self, func):
"""Callable version for use as a decorator
:param func: Function to call initially and every time the
children change. `func` will be called with a
single argument, the list of children.
:type func: callable
"""
if self._used:
raise KazooException(
"A function has already been associated with this "
"ChildrenWatch instance.")
self._func = func
self._used = True
if self._allow_session_lost:
self._client.add_listener(self._session_watcher)
self._get_children()
return func
def __call__(self, func):
"""Callable version for use as a decorator
:param func: Function to call initially and every time the
data changes. `func` will be called with a
tuple, the value of the node and a
:class:`~kazoo.client.ZnodeStat` instance.
:type func: callable
"""
if self._used:
raise KazooException(
"A function has already been associated with this "
"DataWatch instance.")
self._func = func
self._used = True
self._client.add_listener(self._session_watcher)
self._get_data()
return func
