OpenStack Networking (Neutron)
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neutron/neutron/agent/linux/external_process.py

105 lines
3.6 KiB

# 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
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)
class ProcessManager(object):
"""An external process manager for Neutron spawned processes.
Note: The manager expects uuid to be in cmdline.
"""
def __init__(self, conf, uuid, root_helper='sudo',
namespace=None, service=None):
self.conf = conf
self.uuid = uuid
self.root_helper = root_helper
self.namespace = namespace
if service:
self.service_pid_fname = 'pid.' + service
else:
self.service_pid_fname = 'pid'
def enable(self, cmd_callback, reload_cfg=False):
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)
elif reload_cfg:
self.reload_cfg()
def reload_cfg(self):
self.disable('HUP')
def disable(self, sig='9'):
pid = self.pid
if self.active:
cmd = ['kill', '-%s' % (sig), pid]
utils.execute(cmd, self.root_helper)
# In the case of shutting down, remove the pid file
if sig == '9':
utils.remove_conf_file(self.conf.external_pids,
self.uuid,
self.service_pid_fname)
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)
def get_pid_file_name(self, ensure_pids_dir=False):
"""Returns the file name for a given kind of config file."""
return utils.get_conf_file_name(self.conf.external_pids,
self.uuid,
self.service_pid_fname,
ensure_pids_dir)
@property
def pid(self):
"""Last known pid for this external process spawned for this uuid."""
return utils.get_value_from_conf_file(self.conf.external_pids,
self.uuid,
self.service_pid_fname,
int)
@property
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