256 lines
7.9 KiB
Python
256 lines
7.9 KiB
Python
#
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# Copyright (C) 2012-2013 Red Hat, Inc.
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#
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# This copyrighted material is made available to anyone wishing to use,
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# modify, copy, or redistribute it subject to the terms and conditions of
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# the GNU General Public License v.2, or (at your option) any later version.
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# This program is distributed in the hope that it will be useful, but WITHOUT
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# ANY WARRANTY expressed or implied, including the implied warranties of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
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# Public License for more details. You should have received a copy of the
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# GNU General Public License along with this program; if not, write to the
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# Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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# 02110-1301, USA. Any Red Hat trademarks that are incorporated in the
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# source code or documentation are not subject to the GNU General Public
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# License and may only be used or replicated with the express permission of
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# Red Hat, Inc.
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#
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# Red Hat Author(s): Vratislav Podzimek <vpodzime@redhat.com>
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#
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"""
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Module facilitating the work with NTP servers and NTP daemon's configuration
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"""
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from __future__ import division
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import re
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import os
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import tempfile
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import shutil
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import ntplib
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import socket
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from pyanaconda import isys
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from pyanaconda import iutil
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from pyanaconda.threads import threadMgr, AnacondaThread
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from pyanaconda.constants import THREAD_SYNC_TIME_BASENAME
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NTP_CONFIG_FILE = "/etc/chrony.conf"
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#example line:
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#server 0.fedora.pool.ntp.org iburst
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SRV_LINE_REGEXP = re.compile(r"^\s*(server|pool)\s*([-a-zA-Z.0-9]+)\s*[a-zA-Z]+\s*$")
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#treat pools as four servers with the same name
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SERVERS_PER_POOL = 4
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class NTPconfigError(Exception):
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"""Exception class for NTP related problems"""
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pass
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def ntp_server_working(server):
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"""
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Tries to do an NTP request to the $server (timeout may take some time).
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:param server: hostname or IP address of an NTP server
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:type server: string
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:return: True if the given server is reachable and working, False otherwise
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:rtype: bool
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"""
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client = ntplib.NTPClient()
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try:
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client.request(server)
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except ntplib.NTPException:
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return False
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# address related error
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except socket.gaierror:
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return False
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# socket related error
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# (including "Network is unreachable")
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except socket.error:
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return False
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return True
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def pools_servers_to_internal(pools, servers):
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ret = []
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for pool in pools:
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ret.extend(SERVERS_PER_POOL * [pool])
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ret.extend(servers)
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return ret
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def internal_to_pools_and_servers(pools_servers):
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server_nums = dict()
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pools = []
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servers = []
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for item in pools_servers:
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server_nums[item] = server_nums.get(item, 0) + 1
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for item in server_nums.keys():
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if server_nums[item] >= SERVERS_PER_POOL:
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pools.extend((server_nums[item] // SERVERS_PER_POOL) * [item])
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servers.extend((server_nums[item] % SERVERS_PER_POOL) * [item])
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else:
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servers.extend(server_nums[item] * [item])
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return (pools, servers)
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def get_servers_from_config(conf_file_path=NTP_CONFIG_FILE,
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srv_regexp=SRV_LINE_REGEXP):
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"""
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Goes through the chronyd's configuration file looking for lines starting
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with 'server'.
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:return: servers found in the chronyd's configuration
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:rtype: list
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"""
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pools = list()
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servers = list()
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try:
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with open(conf_file_path, "r") as conf_file:
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for line in conf_file:
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match = srv_regexp.match(line)
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if match:
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if match.group(1) == "pool":
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pools.append(match.group(2))
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else:
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servers.append(match.group(2))
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except IOError as ioerr:
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msg = "Cannot open config file %s for reading (%s)" % (conf_file_path,
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ioerr.strerror)
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raise NTPconfigError(msg)
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return (pools, servers)
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def save_servers_to_config(pools, servers, conf_file_path=NTP_CONFIG_FILE,
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srv_regexp=SRV_LINE_REGEXP, out_file_path=None):
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"""
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Replaces the pools and servers defined in the chronyd's configuration file
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with the given ones. If the out_file is not None, then it is used for the
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resulting config.
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:type pools: iterable
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:type servers: iterable
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:param out_file_path: path to the file used for the resulting config
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"""
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try:
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old_conf_file = open(conf_file_path, "r")
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except IOError as ioerr:
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msg = "Cannot open config file %s for reading (%s)" % (conf_file_path,
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ioerr.strerror)
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raise NTPconfigError(msg)
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try:
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if out_file_path:
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new_conf_file = open(out_file_path, "w")
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else:
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(fildes, temp_path) = tempfile.mkstemp()
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new_conf_file = os.fdopen(fildes, "w")
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except IOError as ioerr:
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if out_file_path:
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msg = "Cannot open new config file %s "\
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"for writing (%s)" % (out_file_path, ioerr.strerror)
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else:
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msg = "Cannot open temporary file %s "\
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"for writing (%s)" % (temp_path, ioerr.strerror)
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raise NTPconfigError(msg)
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heading = "# These servers were defined in the installation:\n"
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#write info about the origin of the following lines
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new_conf_file.write(heading)
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#write new servers and pools
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for pool in pools:
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new_conf_file.write("pool " + pool + " iburst\n")
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for server in servers:
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new_conf_file.write("server " + server + " iburst\n")
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#copy non-server lines from the old config and skip our heading
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for line in old_conf_file:
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if not srv_regexp.match(line) and line != heading:
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new_conf_file.write(line)
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old_conf_file.close()
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new_conf_file.close()
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if not out_file_path:
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try:
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stat = os.stat(conf_file_path)
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# Use copy rather then move to get the correct selinux context
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shutil.copy(temp_path, conf_file_path)
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iutil.eintr_retry_call(os.chmod, conf_file_path, stat.st_mode)
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os.unlink(temp_path)
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except OSError as oserr:
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msg = "Cannot replace the old config with "\
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"the new one (%s)" % (oserr.strerror)
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raise NTPconfigError(msg)
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def one_time_sync(server, callback=None):
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"""
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Synchronize the system time with a given NTP server. Note that this
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function is blocking and will not return until the time gets synced or
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querying server fails (may take some time before timeouting).
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:param server: NTP server
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:param callback: callback function to run after sync or failure
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:type callback: a function taking one boolean argument (success)
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:return: True if the sync was successful, False otherwise
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"""
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client = ntplib.NTPClient()
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try:
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results = client.request(server)
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isys.set_system_time(int(results.tx_time))
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success = True
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except ntplib.NTPException:
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success = False
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except socket.gaierror:
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success = False
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if callback is not None:
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callback(success)
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return success
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def one_time_sync_async(server, callback=None):
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"""
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Asynchronously synchronize the system time with a given NTP server. This
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function is non-blocking it starts a new thread for synchronization and
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returns. Use callback argument to specify the function called when the
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new thread finishes if needed.
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:param server: NTP server
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:param callback: callback function to run after sync or failure
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:type callback: a function taking one boolean argument (success)
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"""
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thread_name = "%s_%s" % (THREAD_SYNC_TIME_BASENAME, server)
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if threadMgr.get(thread_name):
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#syncing with the same server running
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return
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threadMgr.add(AnacondaThread(name=thread_name, target=one_time_sync,
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args=(server, callback)))
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