"""Kazoo testing harnesses"""
import atexit
import logging
import os
import uuid
import unittest
from kazoo.client import KazooClient
from kazoo.exceptions import NotEmptyError
from kazoo.protocol.states import (
KazooState
)
from kazoo.testing.common import ZookeeperCluster
from kazoo.protocol.connection import _CONNECTION_DROP, _SESSION_EXPIRED
log = logging.getLogger(__name__)
CLUSTER = None
def get_global_cluster():
global CLUSTER
if CLUSTER is None:
ZK_HOME = os.environ.get("ZOOKEEPER_PATH")
ZK_CLASSPATH = os.environ.get("ZOOKEEPER_CLASSPATH")
ZK_PORT_OFFSET = int(os.environ.get("ZOOKEEPER_PORT_OFFSET", 20000))
assert ZK_HOME or ZK_CLASSPATH, (
"Either ZOOKEEPER_PATH or ZOOKEEPER_CLASSPATH environment "
"variable must be defined.\n"
"For deb package installations this is /usr/share/java")
CLUSTER = ZookeeperCluster(
install_path=ZK_HOME,
classpath=ZK_CLASSPATH,
port_offset=ZK_PORT_OFFSET,
)
atexit.register(lambda cluster: cluster.terminate(), CLUSTER)
return CLUSTER
[docs]class KazooTestHarness(unittest.TestCase):
"""Harness for testing code that uses Kazoo
This object can be used directly or as a mixin. It supports starting
and stopping a complete ZooKeeper cluster locally and provides an
API for simulating errors and expiring sessions.
Example::
class MyTestCase(KazooTestHarness):
def setUp(self):
self.setup_zookeeper()
# additional test setup
def tearDown(self):
self.teardown_zookeeper()
def test_something(self):
something_that_needs_a_kazoo_client(self.client)
def test_something_else(self):
something_that_needs_zk_servers(self.servers)
"""
def __init__(self, *args, **kw):
super(KazooTestHarness, self).__init__(*args, **kw)
self.client = None
self._clients = []
@property
def cluster(self):
return get_global_cluster()
@property
def servers(self):
return ",".join([s.address for s in self.cluster])
def _get_nonchroot_client(self):
return KazooClient(self.servers)
def _get_client(self, **kwargs):
c = KazooClient(self.hosts, **kwargs)
try:
self._clients.append(c)
except AttributeError:
self._client = [c]
return c
def lose_connection(self, event_factory):
"""Force client to lose connection with server"""
self.__break_connection(_CONNECTION_DROP, KazooState.SUSPENDED, event_factory)
def expire_session(self, event_factory):
"""Force ZK to expire a client session"""
self.__break_connection(_SESSION_EXPIRED, KazooState.LOST, event_factory)
def setup_zookeeper(self, **client_options):
"""Create a ZK cluster and chrooted :class:`KazooClient`
The cluster will only be created on the first invocation and won't be
fully torn down until exit.
"""
if not self.cluster[0].running:
self.cluster.start()
namespace = "/kazootests" + uuid.uuid4().hex
self.hosts = self.servers + namespace
if 'timeout' not in client_options:
client_options['timeout'] = 0.8
self.client = self._get_client(**client_options)
self.client.start()
self.client.ensure_path("/")
def teardown_zookeeper(self):
"""Clean up any ZNodes created during the test
"""
if not self.cluster[0].running:
self.cluster.start()
tries = 0
if self.client and self.client.connected:
while tries < 3:
try:
self.client.retry(self.client.delete, '/', recursive=True)
break
except NotEmptyError:
pass
tries += 1
self.client.stop()
self.client.close()
del self.client
else:
client = self._get_client()
client.start()
client.retry(client.delete, '/', recursive=True)
client.stop()
client.close()
del client
for client in self._clients:
client.stop()
del client
self._clients = None
def __break_connection(self, break_event, expected_state, event_factory):
"""Break ZooKeeper connection using the specified event."""
lost = event_factory()
safe = event_factory()
def watch_loss(state):
if state == expected_state:
lost.set()
elif lost.is_set() and state == KazooState.CONNECTED:
safe.set()
return True
self.client.add_listener(watch_loss)
self.client._call(break_event, None)
lost.wait(5)
if not lost.isSet():
raise Exception("Failed to get notified of broken connection.")
safe.wait(15)
if not safe.isSet():
raise Exception("Failed to see client reconnect.")
self.client.retry(self.client.get_async, '/')
[docs]class KazooTestCase(KazooTestHarness):
def setUp(self):
self.setup_zookeeper()
def tearDown(self):
self.teardown_zookeeper()