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)