569b5cd7e9
http://docs.openstack.org/developer/taskflow/utils.html points to http://docs.openstack.org/developer/taskflow/kazoo.readthedocs.org/ - fix the broken URL. Change-Id: I6f6650cef94cea9d6f138925e5e8d2ed6ea177c3
209 lines
8.7 KiB
Python
209 lines
8.7 KiB
Python
# -*- coding: utf-8 -*-
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# Copyright (C) 2014 Yahoo! Inc. All Rights Reserved.
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#
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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from kazoo import client
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from kazoo import exceptions as k_exc
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from oslo_utils import reflection
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import six
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from six.moves import zip as compat_zip
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from taskflow import exceptions as exc
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def _parse_hosts(hosts):
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if isinstance(hosts, six.string_types):
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return hosts.strip()
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if isinstance(hosts, (dict)):
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host_ports = []
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for (k, v) in six.iteritems(hosts):
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host_ports.append("%s:%s" % (k, v))
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hosts = host_ports
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if isinstance(hosts, (list, set, tuple)):
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return ",".join([str(h) for h in hosts])
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return hosts
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def prettify_failures(failures, limit=-1):
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"""Prettifies a checked commits failures (ignores sensitive data...)."""
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prettier = []
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for (op, r) in failures:
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pretty_op = reflection.get_class_name(op, fully_qualified=False)
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# Pick off a few attributes that are meaningful (but one that don't
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# show actual data, which might not be desired to show...).
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selected_attrs = [
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"path=%r" % op.path,
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]
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try:
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if op.version != -1:
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selected_attrs.append("version=%s" % op.version)
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except AttributeError:
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pass
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pretty_op += "(%s)" % (", ".join(selected_attrs))
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pretty_cause = reflection.get_class_name(r, fully_qualified=False)
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prettier.append("%s@%s" % (pretty_cause, pretty_op))
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if limit <= 0 or len(prettier) <= limit:
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return ", ".join(prettier)
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else:
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leftover = prettier[limit:]
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prettier = prettier[0:limit]
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return ", ".join(prettier) + " and %s more..." % len(leftover)
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class KazooTransactionException(k_exc.KazooException):
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"""Exception raised when a checked commit fails."""
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def __init__(self, message, failures):
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super(KazooTransactionException, self).__init__(message)
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self._failures = tuple(failures)
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@property
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def failures(self):
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return self._failures
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def checked_commit(txn):
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"""Commits a kazoo transcation and validates the result.
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NOTE(harlowja): Until https://github.com/python-zk/kazoo/pull/224 is fixed
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or a similar pull request is merged we have to workaround the transaction
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failing silently.
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"""
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if not txn.operations:
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return []
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results = txn.commit()
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failures = []
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for op, result in compat_zip(txn.operations, results):
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if isinstance(result, k_exc.KazooException):
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failures.append((op, result))
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if len(results) < len(txn.operations):
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raise KazooTransactionException(
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"Transaction returned %s results, this is less than"
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" the number of expected transaction operations %s"
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% (len(results), len(txn.operations)), failures)
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if len(results) > len(txn.operations):
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raise KazooTransactionException(
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"Transaction returned %s results, this is greater than"
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" the number of expected transaction operations %s"
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% (len(results), len(txn.operations)), failures)
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if failures:
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raise KazooTransactionException(
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"Transaction with %s operations failed: %s"
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% (len(txn.operations),
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prettify_failures(failures, limit=1)), failures)
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return results
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def finalize_client(client):
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"""Stops and closes a client, even if it wasn't started."""
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client.stop()
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client.close()
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def check_compatible(client, min_version=None, max_version=None):
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"""Checks if a kazoo client is backed by a zookeeper server version.
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This check will verify that the zookeeper server version that the client
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is connected to satisfies a given minimum version (inclusive) and
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maximum (inclusive) version range. If the server is not in the provided
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version range then a exception is raised indiciating this.
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"""
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server_version = None
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if min_version:
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server_version = tuple((int(a) for a in client.server_version()))
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min_version = tuple((int(a) for a in min_version))
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if server_version < min_version:
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pretty_server_version = ".".join([str(a) for a in server_version])
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min_version = ".".join([str(a) for a in min_version])
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raise exc.IncompatibleVersion("Incompatible zookeeper version"
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" %s detected, zookeeper >= %s"
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" required" % (pretty_server_version,
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min_version))
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if max_version:
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if server_version is None:
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server_version = tuple((int(a) for a in client.server_version()))
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max_version = tuple((int(a) for a in max_version))
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if server_version > max_version:
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pretty_server_version = ".".join([str(a) for a in server_version])
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max_version = ".".join([str(a) for a in max_version])
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raise exc.IncompatibleVersion("Incompatible zookeeper version"
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" %s detected, zookeeper <= %s"
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" required" % (pretty_server_version,
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max_version))
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def make_client(conf):
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"""Creates a `kazoo`_ `client`_ given a configuration dictionary.
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:param conf: configuration dictionary that will be used to configure
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the created client
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:type conf: dict
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The keys that will be extracted are:
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- ``read_only``: boolean that specifies whether to allow connections to
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read only servers, defaults to ``False``
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- ``randomize_hosts``: boolean that specifies whether to randomize
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host lists provided, defaults to ``False``
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- ``command_retry``: a kazoo `retry`_ object (or dict of options which
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will be used for creating one) that will be used for retrying commands
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that are executed
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- ``connection_retry``: a kazoo `retry`_ object (or dict of options which
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will be used for creating one) that will be used for retrying
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connection failures that occur
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- ``hosts``: a string, list, set (or dict with host keys) that will
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specify the hosts the kazoo client should be connected to, if none
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is provided then ``localhost:2181`` will be used by default
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- ``timeout``: a float value that specifies the default timeout that the
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kazoo client will use
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- ``handler``: a kazoo handler object that can be used to provide the
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client with alternate async strategies (the default is `thread`_
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based, but `gevent`_, or `eventlet`_ ones can be provided as needed)
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.. _client: http://kazoo.readthedocs.org/en/latest/api/client.html
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.. _kazoo: http://kazoo.readthedocs.org/
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.. _retry: http://kazoo.readthedocs.org/en/latest/api/retry.html
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.. _gevent: http://kazoo.readthedocs.org/en/latest/api/\
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handlers/gevent.html
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.. _eventlet: http://kazoo.readthedocs.org/en/latest/api/\
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handlers/eventlet.html
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.. _thread: http://kazoo.readthedocs.org/en/latest/api/\
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handlers/threading.html
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"""
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# See: http://kazoo.readthedocs.org/en/latest/api/client.html
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client_kwargs = {
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'read_only': bool(conf.get('read_only')),
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'randomize_hosts': bool(conf.get('randomize_hosts')),
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}
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# See: http://kazoo.readthedocs.org/en/latest/api/retry.html
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if 'command_retry' in conf:
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client_kwargs['command_retry'] = conf['command_retry']
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if 'connection_retry' in conf:
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client_kwargs['connection_retry'] = conf['connection_retry']
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hosts = _parse_hosts(conf.get("hosts", "localhost:2181"))
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if not hosts or not isinstance(hosts, six.string_types):
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raise TypeError("Invalid hosts format, expected "
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"non-empty string/list, not '%s' (%s)"
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% (hosts, type(hosts)))
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client_kwargs['hosts'] = hosts
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if 'timeout' in conf:
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client_kwargs['timeout'] = float(conf['timeout'])
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# Kazoo supports various handlers, gevent, threading, eventlet...
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# allow the user of this client object to optionally specify one to be
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# used.
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if 'handler' in conf:
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client_kwargs['handler'] = conf['handler']
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return client.KazooClient(**client_kwargs)
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