class WatchDeliveryConnectionFailedTest(ZookeeperTestCase):
"""Watches are still sent on reconnect.
"""
def setUp(self):
super(WatchDeliveryConnectionFailedTest, self).setUp()
self.proxy = ProxyFactory("127.0.0.1", 2181)
self.proxy_port = reactor.listenTCP(0, self.proxy)
host = self.proxy_port.getHost()
self.proxied_client = ZookeeperClient(
"%s:%s" % (host.host, host.port))
self.direct_client = ZookeeperClient("127.0.0.1:2181", 3000)
self.session_events = []
def session_event_collector(conn, event):
self.session_events.append(event)
self.proxied_client.set_session_callback(session_event_collector)
return self.direct_client.connect()
@inlineCallbacks
def tearDown(self):
zookeeper.set_debug_level(0)
if self.proxied_client.connected:
yield self.proxied_client.close()
if not self.direct_client.connected:
yield self.direct_client.connect()
utils.deleteTree(handle=self.direct_client.handle)
yield self.direct_client.close()
self.proxy.lose_connection()
yield self.proxy_port.stopListening()
def verify_events(self, events, expected):
"""Verify the state of the session events encountered.
"""
for value, state in zip([e.state_name for e in events], expected):
self.assertEqual(value, state)
@inlineCallbacks
def test_child_watch_fires_upon_reconnect(self):
yield self.proxied_client.connect()
# Setup tree
cpath = "/test-tree"
yield self.direct_client.create(cpath)
# Setup watch
child_d, watch_d = self.proxied_client.get_children_and_watch(cpath)
self.assertEqual((yield child_d), [])
# Kill the connection and fire the watch
self.proxy.lose_connection()
yield self.direct_client.create(
cpath + "/abc", flags=zookeeper.SEQUENCE)
# We should still get the child event.
yield watch_d
# We get two pairs of (connecting, connected) for the conn and watch
self.assertEqual(len(self.session_events), 4)
self.verify_events(
self.session_events,
("connecting", "connecting", "connected", "connected"))
@inlineCallbacks
def test_exists_watch_fires_upon_reconnect(self):
yield self.proxied_client.connect()
cpath = "/test"
# Setup watch
exists_d, watch_d = self.proxied_client.exists_and_watch(cpath)
self.assertEqual((yield exists_d), None)
# Kill the connection and fire the watch
self.proxy.lose_connection()
yield self.direct_client.create(cpath)
# We should still get the exists event.
yield watch_d
# We get two pairs of (connecting, connected) for the conn and watch
self.assertEqual(len(self.session_events), 4)
self.verify_events(
self.session_events,
("connecting", "connecting", "connected", "connected"))
@inlineCallbacks
def test_get_watch_fires_upon_reconnect(self):
yield self.proxied_client.connect()
# Setup tree
cpath = "/test"
yield self.direct_client.create(cpath, "abc")
# Setup watch
get_d, watch_d = self.proxied_client.get_and_watch(cpath)
content, stat = yield get_d
self.assertEqual(content, "abc")
# Kill the connection and fire the watch
self.proxy.lose_connection()
yield self.direct_client.set(cpath, "xyz")
# We should still get the exists event.
yield watch_d
# We also two pairs of (connecting, connected) for the conn and watch
self.assertEqual(len(self.session_events), 4)
self.verify_events(
self.session_events,
("connecting", "connecting", "connected", "connected"))
@inlineCallbacks
def test_watch_delivery_failure_resends(self):
"""Simulate a network failure for the watch delivery
The zk server effectively sends the watch delivery to the client,
but the client never recieves it.
"""
yield self.proxied_client.connect()
cpath = "/test"
# Setup watch
exists_d, watch_d = self.proxied_client.exists_and_watch(cpath)
self.assertEqual((yield exists_d), None)
# Pause the connection fire the watch, and blackhole the data.
self.proxy.set_blocked(True)
yield self.direct_client.create(cpath)
self.proxy.set_blocked(False)
self.proxy.lose_connection()
# We should still get the exists event.
yield watch_d
@inlineCallbacks
def xtest_binding_bug_session_exception(self):
"""This test triggers an exception in the python-zookeeper binding.
File "txzookeeper/client.py", line 491, in create
self.handle, path, data, acls, flags, callback)
exceptions.SystemError: error return without exception set
"""
yield self.proxied_client.connect()
data_d, watch_d = yield self.proxied_client.exists_and_watch("/")
self.assertTrue((yield data_d))
self.proxy.set_blocked(True)
# Wait for session expiration, on a single server options are limited
yield self.sleep(15)
# Unblock the proxy for next connect, and then drop the connection.
self.proxy.set_blocked(False)
self.proxy.lose_connection()
# Wait for a reconnect
yield self.assertFailure(watch_d, zookeeper.SessionExpiredException)
# Leads to bindings bug failure
yield self.assertFailure(
self.proxied_client.get("/a"),
zookeeper.SessionExpiredException)
self.assertEqual(self.session_events[-1].state_name, "expired")
class ClientSessionTests(ZookeeperTestCase):
def setUp(self):
super(ClientSessionTests, self).setUp()
self.cluster.start()
self.client = None
self.client2 = None
zookeeper.deterministic_conn_order(True)
zookeeper.set_debug_level(0)
@property
def cluster(self):
return CLUSTER
def tearDown(self):
super(ClientSessionTests, self).tearDown()
if self.client:
self.client.close()
self.cluster.reset()
@inlineCallbacks
def test_client_session_migration(self):
"""A client will automatically rotate servers to ensure a connection.
A client connected to multiple servers, will transparently
migrate amongst them, as individual servers can no longer be
reached. A client's session will be maintined.
"""
# Connect to the Zookeeper Cluster
servers = ",".join([s.address for s in self.cluster])
self.client = ZookeeperClient(servers)
yield self.client.connect()
yield self.client.create("/hello", flags=zookeeper.EPHEMERAL)
# Shutdown the server the client is connected to
self.cluster[0].stop()
# Wait for the shutdown and cycle, if we don't wait we'll
# get a zookeeper connectionloss exception on occassion.
yield self.sleep(0.1)
self.assertTrue(self.client.connected)
exists = yield self.client.exists("/hello")
self.assertTrue(exists)
@inlineCallbacks
def test_client_watch_migration(self):
"""On server rotation, extant watches are still active.
A client connected to multiple servers, will transparently
migrate amongst them, as individual servers can no longer be
reached. Watch deferreds issued from the same client instance will
continue to function as the session is maintained.
"""
session_events = []
def session_event_callback(connection, e):
session_events.append(e)
# Connect to the Zookeeper Cluster
servers = ",".join([s.address for s in self.cluster])
self.client = ZookeeperClient(servers)
self.client.set_session_callback(session_event_callback)
yield self.client.connect()
# Setup a watch
yield self.client.create("/hello")
exists_d, watch_d = self.client.exists_and_watch("/hello")
yield exists_d
# Shutdown the server the client is connected to
self.cluster[0].stop()
# Wait for the shutdown and cycle, if we don't wait we'll
# get occasionally get a zookeeper connectionloss exception.
yield self.sleep(0.1)
# The session events that would have been ignored are sent
# to the session event callback.
self.assertTrue(session_events)
self.assertTrue(self.client.connected)
# If we delete the node, we'll see the watch fire.
yield self.client.delete("/hello")
event = yield watch_d
self.assertEqual(event.type_name, "deleted")
self.assertEqual(event.path, "/hello")
@inlineCallbacks
def test_connection_error_handler(self):
"""A callback can be specified for connection errors.
We can specify a callback for connection errors, that
can perform recovery for a disconnected client, restablishing
"""
@inlineCallbacks
def connection_error_handler(connection, error):
# Moved management of this connection attribute out of the
# default behavior for a connection exception, to support
# the retry facade. Under the hood libzk is going to be
# trying to transparently reconnect
connection.connected = False
# On loss of the connection, reconnect the client w/ same session.
yield connection.connect(
self.cluster[1].address, client_id=connection.client_id)
returnValue(23)
self.client = ZookeeperClient(self.cluster[0].address)
self.client.set_connection_error_callback(connection_error_handler)
yield self.client.connect()
yield self.client.create("/hello")
exists_d, watch_d = self.client.exists_and_watch("/hello")
yield exists_d
# Shutdown the server the client is connected to
self.cluster[0].stop()
yield self.sleep(0.1)
# Results in connection loss exception, and invoking of error handler.
result = yield self.client.exists("/hello")
# The result of the error handler is returned to the api
self.assertEqual(result, 23)
exists = yield self.client.exists("/hello")
self.assertTrue(exists)
@inlineCallbacks
def test_client_session_expiration_event(self):
"""A client which recieves a session expiration event.
"""
session_events = []
events_received = Deferred()
def session_event_callback(connection, e):
session_events.append(e)
if len(session_events) == 8:
events_received.callback(True)
# Connect to a node in the cluster and establish a watch
self.client = ZookeeperClient(self.cluster[0].address)
self.client.set_session_callback(session_event_callback)
yield self.client.connect()
# Setup some watches to verify they are cleaned out on expiration.
d, e_watch_d = self.client.exists_and_watch("/")
yield d
d, g_watch_d = self.client.get_and_watch("/")
yield d
d, c_watch_d = self.client.get_children_and_watch("/")
yield d
# Connect a client to the same session on a different node.
self.client2 = ZookeeperClient(self.cluster[1].address)
yield self.client2.connect(client_id=self.client.client_id)
# Close the new client and wait for the event propogation
yield self.client2.close()
# It can take some time for this to propagate
yield events_received
self.assertEqual(len(session_events), 8)
# The last four (conn + 3 watches) are all expired
for evt in session_events[4:]:
self.assertEqual(evt.state_name, "expired")
# The connection is dead without reconnecting.
yield self.assertFailure(
self.client.exists("/"),
NotConnectedException, ConnectionException)
self.assertTrue(self.client.unrecoverable)
yield self.assertFailure(e_watch_d, zookeeper.SessionExpiredException)
yield self.assertFailure(g_watch_d, zookeeper.SessionExpiredException)
yield self.assertFailure(c_watch_d, zookeeper.SessionExpiredException)
# If a reconnect attempt is made with a dead session id
print "reconnect"
yield self.client.connect(client_id=self.client.client_id)
yield self.assertFailure(
self.client.get_children("/"),
NotConnectedException, ConnectionException)
test_client_session_expiration_event.timeout = 10
@inlineCallbacks
def test_client_reconnect_session_on_different_server(self):
"""On connection failure, An application can choose to use a
new connection with which to reconnect to a different member
of the zookeeper cluster, reacquiring the extant session.
A large obvious caveat to using a new client instance rather
than reconnecting the existing client, is that even though the
session has outstanding watches, the watch callbacks/deferreds
won't be active unless the client instance used to create them
is connected.
"""
session_events = []
def session_event_callback(connection, e):
session_events.append(e)
# Connect to a node in the cluster and establish a watch
self.client = ZookeeperClient(self.cluster[2].address)
self.client.set_session_callback(session_event_callback)
yield self.client.connect()
yield self.client.create("/hello", flags=zookeeper.EPHEMERAL)
self.assertTrue((yield self.client.exists("/hello")))
# Shutdown the server the client is connected to
self.cluster[2].stop()
yield self.sleep(0.1)
# Verify we got a session event regarding the down server
self.assertTrue(session_events)
# Open up a new connection to a different server with same session
self.client2 = ZookeeperClient(self.cluster[0].address)
yield self.client2.connect(client_id=self.client.client_id)
# Close the old disconnected client
self.client.close()
# Verify the ephemeral still exists
exists = yield self.client2.exists("/hello")
self.assertTrue(exists)
# Destroy the session and reconnect
self.client2.close()
yield self.client.connect(self.cluster[0].address)
# Ephemeral is destroyed when the session closed.
exists = yield self.client.exists("/hello")
self.assertFalse(exists)
