def test_data_watcher(self):
"""Test various scenarios for data watcher:
1. When data get changed, watcher callback should be invoked.
2. When the underlying zk client disconnects and then recovers,
the watcher callback should be invoked.
3. When the underlying zk client messes up beyond recovery,
the underlying client should be replaced, and once the new client
is in place, the watcher callback should be invoked again.
"""
data_stat = []
watcher_triggered = Event()
def data_watch(data, stat):
while data_stat:
data_stat.pop()
data_stat.append(data)
data_stat.append(stat)
watcher_triggered.set()
testutil.initialize_kazoo_client_manager(ZK_HOSTS)
client = KazooClientManager().get_client()
client.create(DataWatcherTestCase.TEST_PATH,
DataWatcherTestCase.DATA_0)
data_watcher = DataWatcher(DataWatcherTestCase.TEST_PATH,
ZK_HOSTS,
waiting_in_secs=0.01)
data_watcher.watch(data_watch).join()
watcher_triggered.wait(1)
# Now the data and version should be foo and 0.
self.assertEqual(data_stat[0], DataWatcherTestCase.DATA_0)
self.assertEqual(data_stat[1].version, 0)
watcher_triggered.clear()
client.set(DataWatcherTestCase.TEST_PATH, DataWatcherTestCase.DATA_1)
watcher_triggered.wait(1)
# Make sure that watch callback is triggered.
self.assertEqual(data_stat[0], DataWatcherTestCase.DATA_1)
self.assertEqual(data_stat[1].version, 1)
data_stat.pop()
data_stat.pop()
# Test recoverable failure
watcher_triggered.clear()
client.stop()
client.start()
# Here the client actually will call check the znode in the
# background.
watcher_triggered.wait(1)
# Since nothing changed, no notification from the client.
self.assertFalse(data_stat)
# Test client change
client.stop()
watcher_triggered.clear()
# give the monit greenlet a chance to detect failures.
gevent.sleep(1)
# Assert the client has been replaced with a new one.
self.assertFalse(KazooClientManager().get_client() is client)
watcher_triggered.wait(1)
# Make sure that watch callback is triggered when client is replaced.
self.assertEqual(data_stat[0], DataWatcherTestCase.DATA_1)
self.assertEqual(data_stat[1].version, 1)
def test_data_watcher(self):
"""Test various scenarios for data watcher:
1. When data get changed, watcher callback should be invoked.
2. When the underlying zk client disconnects and then recovers,
the watcher callback should be invoked.
3. When the underlying zk client messes up beyond recovery,
the underlying client should be replaced, and once the new client
is in place, the watcher callback should be invoked again.
"""
data_stat = []
watcher_triggered = Event()
def data_watch(data, stat):
while data_stat:
data_stat.pop()
data_stat.append(data)
data_stat.append(stat)
watcher_triggered.set()
testutil.initialize_kazoo_client_manager(ZK_HOSTS)
client = KazooClientManager().get_client()
client.create(DataWatcherTestCase.TEST_PATH,
DataWatcherTestCase.DATA_0)
data_watcher = DataWatcher(DataWatcherTestCase.TEST_PATH,
ZK_HOSTS,
waiting_in_secs=0.01)
data_watcher.watch(data_watch).join()
watcher_triggered.wait(1)
# Now the data and version should be foo and 0.
self.assertEqual(data_stat[0], DataWatcherTestCase.DATA_0)
self.assertEqual(data_stat[1].version, 0)
watcher_triggered.clear()
client.set(DataWatcherTestCase.TEST_PATH, DataWatcherTestCase.DATA_1)
watcher_triggered.wait(1)
# Make sure that watch callback is triggered.
self.assertEqual(data_stat[0], DataWatcherTestCase.DATA_1)
self.assertEqual(data_stat[1].version, 1)
data_stat.pop()
data_stat.pop()
# Test recoverable failure
watcher_triggered.clear()
client.stop()
client.start()
# Here the client actually will call check the znode in the
# background.
watcher_triggered.wait(1)
# Since nothing changed, no notification from the client.
self.assertFalse(data_stat)
# Test client change
client.stop()
watcher_triggered.clear()
# give the monit greenlet a chance to detect failures.
gevent.sleep(1)
# Assert the client has been replaced with a new one.
self.assertFalse(KazooClientManager().get_client() is client)
watcher_triggered.wait(1)
# Make sure that watch callback is triggered when client is replaced.
self.assertEqual(data_stat[0], DataWatcherTestCase.DATA_1)
self.assertEqual(data_stat[1].version, 1)
