openstack/kuryr-kubernetes
Code Issues Proposed changes

Watcher implementation

Browse Source 
Adds Watcher implementation

Change-Id: I9230d6f8cc2ee9346ef29e47bd6fd4f64bd9425e
Partially-Implements: blueprint kuryr-k8s-integration
This commit is contained in:
Ilya Chukhnakov 2016-09-26 00:57:07 +03:00
parent 3477c58e4b
commit 6666459912
5 changed files with 493 additions and 0 deletions
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17
kuryr_kubernetes/constants.py Normal file
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@ -0,0 +1,17 @@
# Copyright (c) 2016 Mirantis, Inc.
# All Rights Reserved.
#
# 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.
K8S_API_BASE = '/api/v1'
K8S_API_NAMESPACES = K8S_API_BASE + '/namespaces'

10
kuryr_kubernetes/controller/service.py
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@ -21,6 +21,8 @@ from oslo_service import service
from kuryr_kubernetes import clients
from kuryr_kubernetes import config
from kuryr_kubernetes import constants
from kuryr_kubernetes import watcher
LOG = logging.getLogger(__name__)
@ -31,9 +33,16 @@ class KuryrK8sService(service.Service):
def __init__(self):
super(KuryrK8sService, self).__init__()
def dummy_handler(event):
LOG.debug("Event: %r", event)
self.watcher = watcher.Watcher(dummy_handler, self.tg)
self.watcher.add(constants.K8S_API_NAMESPACES)
def start(self):
LOG.info(_LI("Service '%s' starting"), self.__class__.__name__)
super(KuryrK8sService, self).start()
self.watcher.start()
LOG.info(_LI("Service '%s' started"), self.__class__.__name__)
def wait(self):
@ -42,6 +51,7 @@ class KuryrK8sService(service.Service):
def stop(self, graceful=False):
LOG.info(_LI("Service '%s' stopping"), self.__class__.__name__)
self.watcher.stop()
super(KuryrK8sService, self).stop(graceful)

27
kuryr_kubernetes/tests/unit/kuryr_fixtures.py Normal file
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@ -0,0 +1,27 @@
# Copyright (c) 2016 Mirantis, Inc.
# All Rights Reserved.
#
# 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 fixtures
import mock
from kuryr_kubernetes import k8s_client
class MockK8sClient(fixtures.Fixture):
def _setUp(self):
self.client = mock.Mock(k8s_client.K8sClient)
self.useFixture(fixtures.MockPatch(
'kuryr_kubernetes.clients.get_kubernetes_client',
lambda: self.client))

291
kuryr_kubernetes/tests/unit/test_watcher.py Normal file
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@ -0,0 +1,291 @@
# Copyright (c) 2016 Mirantis, Inc.
# All Rights Reserved.
#
# 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.
from eventlet import greenlet
import mock
from kuryr_kubernetes.tests import base as test_base
from kuryr_kubernetes.tests.unit import kuryr_fixtures as kuryr_fixtures
from kuryr_kubernetes import watcher
class TestWatcher(test_base.TestCase):
def setUp(self):
super(TestWatcher, self).setUp()
mock_client = self.useFixture(kuryr_fixtures.MockK8sClient())
self.client = mock_client.client
@mock.patch.object(watcher.Watcher, '_start_watch')
def test_add(self, m_start_watch):
paths = ['/test%s' % i for i in range(3)]
m_handler = mock.Mock()
watcher_obj = watcher.Watcher(m_handler)
for path in paths:
watcher_obj.add(path)
self.assertEqual(set(paths), watcher_obj._resources)
m_start_watch.assert_not_called()
@mock.patch.object(watcher.Watcher, '_start_watch')
def test_add_running(self, m_start_watch):
paths = ['/test%s' % i for i in range(3)]
m_handler = mock.Mock()
watcher_obj = watcher.Watcher(m_handler)
watcher_obj._running = True
for path in paths:
watcher_obj.add(path)
self.assertEqual(set(paths), watcher_obj._resources)
m_start_watch.assert_has_calls([mock.call(path) for path in paths],
any_order=True)
@mock.patch.object(watcher.Watcher, '_start_watch')
def test_add_watching(self, m_start_watch):
paths = ['/test%s' % i for i in range(3)]
m_handler = mock.Mock()
watcher_obj = watcher.Watcher(m_handler)
watcher_obj._running = True
m_watching = watcher_obj._watching = mock.MagicMock()
m_watching.__contains__.return_value = True
for path in paths:
watcher_obj.add(path)
self.assertEqual(set(paths), watcher_obj._resources)
m_start_watch.assert_not_called()
@mock.patch.object(watcher.Watcher, '_stop_watch')
def test_remove(self, m_stop_watch):
path = '/test'
m_handler = mock.Mock()
watcher_obj = watcher.Watcher(m_handler)
watcher_obj._resources.add(path)
watcher_obj.remove(path)
self.assertEqual(set(), watcher_obj._resources)
m_stop_watch.assert_not_called()
@mock.patch.object(watcher.Watcher, '_stop_watch')
def test_remove_watching(self, m_stop_watch):
path = '/test'
m_handler = mock.Mock()
watcher_obj = watcher.Watcher(m_handler)
watcher_obj._resources.add(path)
m_watching = watcher_obj._watching = mock.MagicMock()
m_watching.__contains__.return_value = True
watcher_obj.remove(path)
self.assertEqual(set(), watcher_obj._resources)
m_stop_watch.assert_called_once_with(path)
@mock.patch.object(watcher.Watcher, '_start_watch')
def test_start(self, m_start_watch):
paths = ['/test%s' % i for i in range(3)]
m_handler = mock.Mock()
watcher_obj = watcher.Watcher(m_handler)
watcher_obj._resources.update(paths)
watcher_obj.start()
self.assertTrue(watcher_obj._running)
m_start_watch.assert_has_calls([mock.call(path) for path in paths],
any_order=True)
@mock.patch.object(watcher.Watcher, '_start_watch')
def test_start_already_watching(self, m_start_watch):
paths = ['/test%s' % i for i in range(3)]
m_handler = mock.Mock()
watcher_obj = watcher.Watcher(m_handler)
watcher_obj._resources.update(paths)
m_watching = watcher_obj._watching = mock.MagicMock()
m_watching.__iter__.return_value = paths
watcher_obj.start()
self.assertTrue(watcher_obj._running)
m_start_watch.assert_not_called()
@mock.patch.object(watcher.Watcher, '_stop_watch')
def test_stop(self, m_stop_watch):
paths = ['/test%s' % i for i in range(3)]
m_handler = mock.Mock()
watcher_obj = watcher.Watcher(m_handler)
watcher_obj._resources.update(paths)
watcher_obj.stop()
self.assertFalse(watcher_obj._running)
m_stop_watch.assert_not_called()
@mock.patch.object(watcher.Watcher, '_stop_watch')
def test_stop_watching(self, m_stop_watch):
paths = ['/test%s' % i for i in range(3)]
m_handler = mock.Mock()
watcher_obj = watcher.Watcher(m_handler)
watcher_obj._resources.update(paths)
m_watching = watcher_obj._watching = mock.MagicMock()
m_watching.__iter__.return_value = paths
watcher_obj.stop()
self.assertFalse(watcher_obj._running)
m_stop_watch.assert_has_calls([mock.call(path) for path in paths],
any_order=True)
@mock.patch.object(watcher.Watcher, '_watch')
def test_start_watch(self, m_watch):
path = '/test'
m_handler = mock.Mock()
watcher_obj = watcher.Watcher(m_handler)
watcher_obj._start_watch(path)
m_watch.assert_called_once_with(path)
self.assertTrue(watcher_obj._idle.get(path))
self.assertIn(path, watcher_obj._watching)
def test_start_watch_threaded(self):
path = '/test'
m_tg = mock.Mock()
m_tg.add_thread.return_value = mock.sentinel.watch_thread
m_handler = mock.Mock()
watcher_obj = watcher.Watcher(m_handler, m_tg)
watcher_obj._start_watch(path)
m_tg.add_thread.assert_called_once_with(watcher_obj._watch, path)
self.assertTrue(watcher_obj._idle.get(path))
self.assertEqual(mock.sentinel.watch_thread,
watcher_obj._watching.get(path))
def test_stop_watch_threaded(self):
path = '/test'
m_tg = mock.Mock()
m_th = mock.Mock()
m_handler = mock.Mock()
watcher_obj = watcher.Watcher(m_handler, m_tg)
watcher_obj._idle[path] = True
watcher_obj._watching[path] = m_th
watcher_obj._stop_watch(path)
m_th.kill.assert_called()
def test_stop_watch_idle(self):
path = '/test'
m_tg = mock.Mock()
m_th = mock.Mock()
m_handler = mock.Mock()
watcher_obj = watcher.Watcher(m_handler, m_tg)
watcher_obj._idle[path] = False
watcher_obj._watching[path] = m_th
watcher_obj._stop_watch(path)
m_th.kill.assert_not_called()
def _test_watch_mock_events(self, watcher_obj, events):
def client_watch(client_path):
for e in events:
self.assertTrue(watcher_obj._idle[client_path])
yield e
self.assertTrue(watcher_obj._idle[client_path])
self.client.watch.side_effect = client_watch
@staticmethod
def _test_watch_create_watcher(path, handler):
watcher_obj = watcher.Watcher(handler)
watcher_obj._running = True
watcher_obj._resources.add(path)
watcher_obj._idle[path] = True
watcher_obj._watching[path] = None
return watcher_obj
def test_watch(self):
path = '/test'
events = [{'e': i} for i in range(3)]
def handler(event):
self.assertFalse(watcher_obj._idle[path])
m_handler = mock.Mock()
m_handler.side_effect = handler
watcher_obj = self._test_watch_create_watcher(path, m_handler)
self._test_watch_mock_events(watcher_obj, events)
watcher_obj._watch(path)
m_handler.assert_has_calls([mock.call(e) for e in events])
def test_watch_stopped(self):
path = '/test'
events = [{'e': i} for i in range(3)]
def handler(event):
self.assertFalse(watcher_obj._idle[path])
watcher_obj._running = False
m_handler = mock.Mock()
m_handler.side_effect = handler
watcher_obj = self._test_watch_create_watcher(path, m_handler)
self._test_watch_mock_events(watcher_obj, events)
watcher_obj._watch(path)
m_handler.assert_called_once_with(events[0])
self.assertNotIn(path, watcher_obj._idle)
self.assertNotIn(path, watcher_obj._watching)
def test_watch_removed(self):
path = '/test'
events = [{'e': i} for i in range(3)]
def handler(event):
self.assertFalse(watcher_obj._idle[path])
watcher_obj._resources.remove(path)
m_handler = mock.Mock()
m_handler.side_effect = handler
watcher_obj = self._test_watch_create_watcher(path, m_handler)
self._test_watch_mock_events(watcher_obj, events)
watcher_obj._watch(path)
m_handler.assert_called_once_with(events[0])
self.assertNotIn(path, watcher_obj._idle)
self.assertNotIn(path, watcher_obj._watching)
def test_watch_interrupted(self):
path = '/test'
events = [{'e': i} for i in range(3)]
def handler(event):
self.assertFalse(watcher_obj._idle[path])
raise greenlet.GreenletExit()
m_handler = mock.Mock()
m_handler.side_effect = handler
watcher_obj = self._test_watch_create_watcher(path, m_handler)
self._test_watch_mock_events(watcher_obj, events)
self.assertRaises(greenlet.GreenletExit, watcher_obj._watch, path)
m_handler.assert_called_once_with(events[0])
self.assertNotIn(path, watcher_obj._idle)
self.assertNotIn(path, watcher_obj._watching)

148
kuryr_kubernetes/watcher.py Normal file
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@ -0,0 +1,148 @@
# Copyright (c) 2016 Mirantis, Inc.
# All Rights Reserved.
#
# 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.
from kuryr.lib._i18n import _LI
from oslo_log import log as logging
from kuryr_kubernetes import clients
LOG = logging.getLogger(__name__)
class Watcher(object):
"""Observes K8s resources' events using K8s '?watch=true' API.
The `Watcher` maintains a list of K8s resources and manages the event
processing loops for those resources. Event handling is delegated to the
`callable` object passed as the `handler` initialization parameter that
will be run for each K8s event observed by the `Watcher`.
The `Watcher` can operate in two different modes based on the
`thread_group` initialization parameter:
- synchronous, when the event processing loops run on the same thread
that called 'add' or 'start' methods
- asynchronous, when each event processing loop runs on its own thread
(`oslo_service.threadgroup.Thread`) from the `thread_group`
When started, the `Watcher` will run the event processing loops for each
of the K8s resources on the list. Adding a K8s resource to the running
`Watcher` also ensures that the event processing loop for that resource is
running.
Stopping the `Watcher` or removing the specific K8s resource from the
list will request the corresponding running event processing loops to
stop gracefully, but will not interrupt any running `handler`. Forcibly
stopping any 'stuck' `handler` is not supported by the `Watcher` and
should be handled externally (e.g. by using `thread_group.stop(
graceful=False)` for asynchronous `Watcher`).
"""
def __init__(self, handler, thread_group=None):
"""Initializes a new Watcher instance.
:param handler: a `callable` object to be invoked for each observed
K8s event with the event body as a single argument.
Calling `handler` should never raise any exceptions
other than `eventlet.greenlet.GreenletExit` caused by
`eventlet.greenthread.GreenThread.kill` when the
`Watcher` is operating in asynchronous mode.
:param thread_group: an `oslo_service.threadgroup.ThreadGroup`
object used to run the event processing loops
asynchronously. If `thread_group` is not
specified, the `Watcher` will operate in a
synchronous mode.
"""
self._client = clients.get_kubernetes_client()
self._handler = handler
self._thread_group = thread_group
self._running = False
self._resources = set()
self._watching = {}
self._idle = {}
def add(self, path):
"""Adds ths K8s resource to the Watcher.
Adding a resource to a running `Watcher` also ensures that the event
processing loop for that resource is running. This method could block
for `Watcher`s operating in synchronous mode.
:param path: K8s resource URL path
"""
self._resources.add(path)
if self._running and path not in self._watching:
self._start_watch(path)
def remove(self, path):
"""Removes the K8s resource from the Watcher.
Also requests the corresponding event processing loop to stop if it
is running.
:param path: K8s resource URL path
"""
self._resources.discard(path)
if path in self._watching:
self._stop_watch(path)
def start(self):
"""Starts the Watcher.
Also ensures that the event processing loops are running. This method
could block for `Watcher`s operating in synchronous mode.
"""
self._running = True
for path in self._resources - set(self._watching):
self._start_watch(path)
def stop(self):
"""Stops the Watcher.
Also requests all running event processing loops to stop.
"""
self._running = False
for path in list(self._watching):
self._stop_watch(path)
def _start_watch(self, path):
tg = self._thread_group
self._idle[path] = True
if tg:
self._watching[path] = tg.add_thread(self._watch, path)
else:
self._watching[path] = None
self._watch(path)
def _stop_watch(self, path):
if self._idle.get(path):
if self._thread_group:
self._watching[path].kill()
def _watch(self, path):
try:
LOG.info(_LI("Started watching '%s'"), path)
for event in self._client.watch(path):
self._idle[path] = False
self._handler(event)
self._idle[path] = True
if not (self._running and path in self._resources):
return
finally:
self._watching.pop(path)
self._idle.pop(path)
LOG.info(_LI("Stopped watching '%s'"), path)