vmware-nsx/neutron/agent/linux/ovsdb_monitor.py
John Schwarz 02ee2f3962 Fix leftover Timeout effecting most eventlet calls
When registering a new eventlet.timeout.Timeout object, eventlet
automatically starts a timer for most (if not all) future eventlet
calls. Normally, eventlet codes do not hold a timeout unless such a
timeout is used or a specific timeout length is specified through
the API, but once a Timeout object is initialized, it is left there
unless canceled.

This change fixes an un-canceled Timeout which causes some
functional tests to fail, reintroduces a fix for bug #1358206,
which was written prior to discovering the uncanceled timeout, and
increases the timeout of a test that depended on this timeout.

Closes-bug: #1358206
Related-bug: #1364171
Change-Id: I1bfc5af6917c525894eecd8b477d787763edbd02
2014-09-04 14:03:31 +03:00

106 lines
3.6 KiB
Python

# Copyright 2013 Red Hat, Inc.
#
# 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.
import eventlet
from neutron.agent.linux import async_process
from neutron.openstack.common import log as logging
LOG = logging.getLogger(__name__)
class OvsdbMonitor(async_process.AsyncProcess):
"""Manages an invocation of 'ovsdb-client monitor'."""
def __init__(self, table_name, columns=None, format=None,
root_helper=None, respawn_interval=None):
cmd = ['ovsdb-client', 'monitor', table_name]
if columns:
cmd.append(','.join(columns))
if format:
cmd.append('--format=%s' % format)
super(OvsdbMonitor, self).__init__(cmd,
root_helper=root_helper,
respawn_interval=respawn_interval)
def _read_stdout(self):
data = self._process.stdout.readline()
if not data:
return
self._stdout_lines.put(data)
LOG.debug(_('Output received from ovsdb monitor: %s') % data)
return data
def _read_stderr(self):
data = super(OvsdbMonitor, self)._read_stderr()
if data:
LOG.error(_('Error received from ovsdb monitor: %s') % data)
# Do not return value to ensure that stderr output will
# stop the monitor.
class SimpleInterfaceMonitor(OvsdbMonitor):
"""Monitors the Interface table of the local host's ovsdb for changes.
The has_updates() method indicates whether changes to the ovsdb
Interface table have been detected since the monitor started or
since the previous access.
"""
def __init__(self, root_helper=None, respawn_interval=None):
super(SimpleInterfaceMonitor, self).__init__(
'Interface',
columns=['name', 'ofport'],
format='json',
root_helper=root_helper,
respawn_interval=respawn_interval,
)
self.data_received = False
@property
def is_active(self):
return (self.data_received and
self._kill_event and
not self._kill_event.ready())
@property
def has_updates(self):
"""Indicate whether the ovsdb Interface table has been updated.
True will be returned if the monitor process is not active.
This 'failing open' minimizes the risk of falsely indicating
the absence of updates at the expense of potential false
positives.
"""
return bool(list(self.iter_stdout())) or not self.is_active
def start(self, block=False, timeout=5):
super(SimpleInterfaceMonitor, self).start()
if block:
with eventlet.timeout.Timeout(timeout):
while not self.is_active:
eventlet.sleep()
def _kill(self, *args, **kwargs):
self.data_received = False
super(SimpleInterfaceMonitor, self)._kill(*args, **kwargs)
def _read_stdout(self):
data = super(SimpleInterfaceMonitor, self)._read_stdout()
if data and not self.data_received:
self.data_received = True
return data