/usr/share/pyshared/txzookeeper/tests/test_session.py is in python-txzookeeper 0.9.5-0ubuntu1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 | #
# Copyright (C) 2010-2011 Canonical Ltd. All Rights Reserved
#
# This file is part of txzookeeper.
#
# Authors:
# Kapil Thangavelu
#
# txzookeeper is free software: you can redistribute it and/or modify
# it under the terms of the GNU Lesser General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# txzookeeper is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public License
# along with txzookeeper. If not, see <http://www.gnu.org/licenses/>.
#
import atexit
import os
import zookeeper
from twisted.internet.defer import inlineCallbacks, Deferred, returnValue
from txzookeeper import ZookeeperClient
from txzookeeper.client import NotConnectedException, ConnectionException
from txzookeeper.tests.common import ZookeeperCluster
from txzookeeper.tests import ZookeeperTestCase
ZK_HOME = os.environ.get("ZOOKEEPER_PATH")
assert ZK_HOME, (
"ZOOKEEPER_PATH environment variable must be defined.\n "
"For deb package installations this is /usr/share/java")
CLUSTER = ZookeeperCluster(ZK_HOME)
atexit.register(lambda cluster: cluster.terminate(), CLUSTER)
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()
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[0].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
#yield self.client.connect(client_id=self.client.client_id)
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)
exists_d, watch_d = self.client.exists_and_watch("/hello")
yield exists_d
# 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)
|