85 lines
2.8 KiB
Python
85 lines
2.8 KiB
Python
# Copyright 2019 Red Hat, Inc.
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# 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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import re
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import eventlet
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from neutron.agent.common import async_process
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class OFEvent(object):
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def __init__(self, event_type, flow):
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self.event_type = event_type
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self.flow = flow
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class OFMonitor(async_process.AsyncProcess):
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"""Wrapper over 'ovs-ofctl monitor'.
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This is an interactive OpenFlow monitor. By default, when the object is
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instantiated, the monitor process is started. To retrieve the pending
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events, the property "of_events" can be retrieved.
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NOTE(ralonsoh): 'ovs-ofctl monitor' command is sending existing flows to
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stdout pipe (startup first messages) and next incoming messages to stderr
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pipe. That's why this class joins both outputs in one single queue
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(self._queue).
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"""
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EVENT_RE = re.compile(
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r"event=(?P<action>ADDED|DELETED|MODIFIED) (?P<flow>.*)")
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def __init__(self, bridge_name, namespace=None, respawn_interval=None,
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start=True):
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cmd = ['ovs-ofctl', 'monitor', bridge_name, 'watch:', '--monitor']
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super(OFMonitor, self).__init__(cmd, run_as_root=True,
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respawn_interval=respawn_interval,
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namespace=namespace)
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if start:
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self.start()
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self._queue = eventlet.queue.Queue()
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eventlet.spawn(self._read_and_enqueue, self.iter_stdout)
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eventlet.spawn(self._read_and_enqueue, self.iter_stderr)
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def _read_and_enqueue(self, iter):
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for event_line in iter(block=True):
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event = self._parse_event_line(event_line)
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if event:
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self._queue.put(event)
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@property
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def of_events(self):
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events = []
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while not self._queue.empty():
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events.append(self._queue.get())
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return events
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def _parse_event_line(self, event_line):
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match = self.EVENT_RE.match(event_line)
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if match is None:
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return
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return OFEvent(match.group('action'), match.group('flow'))
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def start(self, **kwargs):
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if not self._is_running:
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super(OFMonitor, self).start(block=True)
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def stop(self, **kwargs):
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if self._is_running:
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super(OFMonitor, self).stop(block=True)
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