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OpenStack Study: external_process.py**** CubicPower OpenStack Study ****
# vim: tabstop=4 shiftwidth=4 softtabstop=4 # # Copyright 2012 New Dream Network, LLC (DreamHost) # # Licensed under the Apache License, Version 2.0 (the "License"); you may # not use this file except in compliance with the License. You may obtain # a copy of the License at # # http://www.apache.org/licenses/LICENSE-2.0 # # Unless required by applicable law or agreed to in writing, software # distributed under the License is distributed on an "AS IS" BASIS, WITHOUT # WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the # License for the specific language governing permissions and limitations # under the License. # # @author: Mark McClain, DreamHost import os from oslo.config import cfg from neutron.agent.linux import ip_lib from neutron.agent.linux import utils from neutron.openstack.common import log as logging LOG = logging.getLogger(__name__) OPTS = [ cfg.StrOpt('external_pids', default='$state_path/external/pids', help=_('Location to store child pid files')), ] cfg.CONF.register_opts(OPTS)
**** CubicPower OpenStack Study **** class ProcessManager(object): """An external process manager for Neutron spawned processes. Note: The manager expects uuid to be in cmdline. """
**** CubicPower OpenStack Study **** def __init__(self, conf, uuid, root_helper='sudo', namespace=None): self.conf = conf self.uuid = uuid self.root_helper = root_helper self.namespace = namespace
**** CubicPower OpenStack Study **** def enable(self, cmd_callback): if not self.active: cmd = cmd_callback(self.get_pid_file_name(ensure_pids_dir=True)) ip_wrapper = ip_lib.IPWrapper(self.root_helper, self.namespace) ip_wrapper.netns.execute(cmd)
**** CubicPower OpenStack Study **** def disable(self): pid = self.pid if self.active: cmd = ['kill', '-9', pid] utils.execute(cmd, self.root_helper) elif pid: LOG.debug(_('Process for %(uuid)s pid %(pid)d is stale, ignoring ' 'command'), {'uuid': self.uuid, 'pid': pid}) else: LOG.debug(_('No process started for %s'), self.uuid)
**** CubicPower OpenStack Study **** def get_pid_file_name(self, ensure_pids_dir=False): """Returns the file name for a given kind of config file.""" pids_dir = os.path.abspath(os.path.normpath(self.conf.external_pids)) if ensure_pids_dir and not os.path.isdir(pids_dir): os.makedirs(pids_dir, 0o755) return os.path.join(pids_dir, self.uuid + '.pid') @property
**** CubicPower OpenStack Study **** def pid(self): """Last known pid for this external process spawned for this uuid.""" file_name = self.get_pid_file_name() msg = _('Error while reading %s') try: with open(file_name, 'r') as f: return int(f.read()) except IOError: msg = _('Unable to access %s') except ValueError: msg = _('Unable to convert value in %s') LOG.debug(msg, file_name) return None @property
**** CubicPower OpenStack Study **** def active(self): pid = self.pid if pid is None: return False cmdline = '/proc/%s/cmdline' % pid try: with open(cmdline, "r") as f: return self.uuid in f.readline() except IOError: return False
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