Introduce the translator layer
This commit introduces the translation layer to call Neutron API, as well as the config_map that glues the watcher layer to the translation layer, and it makes it configurable. It simplifies a lot the watcher layer, making trivial to create new ones and relies all the business logic to the translation layer. That introduces the option to some people extend the project by creating custom translators by implementing a simple interface and using another config_map. Partial-Implements: blueprint kuryr-k8s-integration Change-Id: I1c8bcfe1f37f28e833dd2d4631d011f044fd9c47 Signed-off-by: Jaume Devesa <devvesa@gmail.com>
This commit is contained in:
Jaume Devesa
parent
aa0139e56b
commit
7e550f3936
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@ -12,6 +12,13 @@
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import pbr.version
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from kuryr_kubernetes.translators import port
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from kuryr_kubernetes import watchers
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__version__ = pbr.version.VersionInfo(
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'kuryr_kubernetes').version_string()
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CONFIG_MAP = {
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watchers.PodWatcher: [port.PortTranslator]
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}
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@ -34,6 +34,10 @@ k8s_opts = [
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cfg.StrOpt('api_root',
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help=_("The root URL of the Kubernetes API"),
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default=os.environ.get('K8S_API', 'http://localhost:8080')),
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cfg.StrOpt('config_map',
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help=_("The dict that stores the relationships between watchers and"
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" translators."),
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default=('kuryr_kubernetes.CONFIG_MAP'))
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]
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@ -13,12 +13,13 @@
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import asyncio
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import sys
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from kuryr.lib._i18n import _LI
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from kuryr.lib._i18n import _LI, _LE
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from oslo_log import log as logging
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from oslo_service import service
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from oslo_utils import excutils
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from oslo_utils import importutils
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from kuryr_kubernetes import config
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from kuryr_kubernetes.watchers import pod
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LOG = logging.getLogger(__name__)
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@ -38,20 +39,25 @@ class KuryrK8sService(service.Service):
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def __init__(self):
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super(KuryrK8sService, self).__init__()
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self._event_loop = asyncio.new_event_loop()
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self._watchers = [
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pod.PodWatcher
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]
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def start(self):
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LOG.info(_LI("Service '%(class_name)s' started"),
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{'class_name': self.__class__.__name__})
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for watcher in self._watchers:
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instance = watcher(self._event_loop)
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self._event_loop.create_task(instance.watch())
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try:
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config_map = importutils.import_class(
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config.CONF.kubernetes.config_map)
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for watcher, translators in config_map.items():
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instance = watcher(self._event_loop, translators)
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self._event_loop.create_task(instance.watch())
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self._event_loop.run_forever()
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self._event_loop.close()
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except ImportError:
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with excutils.save_and_reraise_exception():
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LOG.exception(_LE("Error loading config_map '%(map)s'"),
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{'map': config.CONF.kubernetes.config_map})
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except Exception:
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sys.exit(1)
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sys.exit(0)
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@ -9,30 +9,33 @@
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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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from kuryr.lib._i18n import _LI
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from oslo_log import log as logging
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from kuryr_kubernetes.watchers import base
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LOG = logging.getLogger(__name__)
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import abc
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class PodWatcher(base.AbstractBaseWatcher):
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class AbstractBaseTranslator(object):
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"""Abstract Translator class. """
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ENDPOINT = "/api/v1/pods"
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def __init__(self):
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# TODO(devvesa) initialize neutron client
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pass
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def __init__(self, event_loop):
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super().__init__(event_loop)
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@abc.abstractmethod
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def get_annotation(self):
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"""Kubernetes annotation to update.
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def get_api_endpoint(self):
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return self.ENDPOINT
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Return the kubernetes annotation that we want to update once each
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task is finished.
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"""
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pass
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@abc.abstractmethod
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async def on_add(self, event): # flake8: noqa
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LOG.info(_LI('Received an ADDED event on a Pod'))
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async def on_modify(self, event):
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LOG.info(_LI('Received a MODIFIED event on a Pod'))
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pass
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@abc.abstractmethod
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async def on_delete(self, event):
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LOG.info(_LI('Received a DELETED event on a Pod'))
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pass
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@abc.abstractmethod
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async def on_modify(self, event):
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pass
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@ -0,0 +1,41 @@
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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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from kuryr.lib._i18n import _LI
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from oslo_log import log as logging
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from kuryr_kubernetes.translators import base
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LOG = logging.getLogger(__name__)
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class PortTranslator(base.AbstractBaseTranslator):
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def __init__(self):
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super().__init__()
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def get_annotation(self):
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return 'kuryr.kubernetes.org/neutron-port'
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async def on_add(self, event): # flake8: noqa
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LOG.info(_LI('Creating a port'))
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# TODO(devvesa): remove this part ASAP. This statement it only applies
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# when checking that the result is serialized on a real K8s. We don't
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# have any end-to-end test yet, so it allows reviewers to see that
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# works.
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return {'port-created': False}
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async def on_modify(self, event):
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LOG.info(_LI('Modifying a port'))
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async def on_delete(self, event):
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LOG.info(_LI('Deleting a port'))
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@ -0,0 +1,201 @@
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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 abc
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import asyncio
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import functools
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import requests
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from kuryr.lib._i18n import _LI, _LW, _LE
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from oslo_log import log as logging
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from oslo_serialization import jsonutils
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from kuryr_kubernetes.aio import headers as aio_headers
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from kuryr_kubernetes.aio import methods as aio_methods
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from kuryr_kubernetes import config
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from kuryr_kubernetes import utils
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LOG = logging.getLogger(__name__)
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ADDED_EVENT = 'ADDED'
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DELETED_EVENT = 'DELETED'
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MODIFIED_EVENT = 'MODIFIED'
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class AbstractBaseWatcher(object):
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"""Base abstract watcher.
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This class implements the default interface for the KuryrK8sService task
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scheduler, which is the `watch` (no parameters) interface.
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It takes care of the events that receives and it triggers the appropiate
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action on the translators configured on the config.kubernetes.config_map
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structure.
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Actual watchers will only need to define the 'get_api_endpoint' method
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that return an String URL in order to suscribe to Kubernetes API events.
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(See :class PodWatcher: below).
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"""
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def __init__(self, event_loop, translators):
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self._event_loop = event_loop
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self._translators = translators
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self._k8s_root = config.CONF.kubernetes.api_root
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async def _get_chunked_connection(self): # flake8: noqa
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"""Get the connection response from Kubernetes API.
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Initializes the connection with Kubernetes API. Since the content type
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is Chunked (http://en.wikipedia.org/wiki/Chunked_transfer_encoding), the
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connection remains open.
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"""
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connection = await aio_methods.get(
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endpoint=self.api_endpoint,
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loop=self._event_loop,
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decoder=utils.utf8_json_decoder)
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status, reason, hdrs = await connection.read_headers()
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if status != requests.codes.ok: # Function returns 200
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LOG.error(_LE('GET request to endpoint %(ep)s failed with '
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'status %(status)s and reason %(reason)s'),
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{'ep': endpoint, 'status': status, 'reason': reason})
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raise requests.exceptions.HTTPError('{}: {}. Endpoint {}'.format(
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status, reason, endpoint))
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if hdrs.get(aio_headers.TRANSFER_ENCODING) != 'chunked':
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LOG.error(_LE('watcher GET request to endpoint %(ep)s is not '
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'chunked. headers: %(hdrs)s'),
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{'ep': endpoint, 'hdrs': hdrs})
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raise IOError(_('Can only watch endpoints that returned chunked '
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'encoded transfers'))
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return connection
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def _update_annotation(self, self_link, annotation, future):
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"""Update K8s entities' annotations
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This method is the callback of all the tasks scheduled in the
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'self._on_event' method.
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In case the _on_event 'future' returns something different that None, it
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will update the annotations in resource defined by 'self_link' with the
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key 'annotation' and value 'future.get_result()'
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:param self_link: Entity link to update.
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:param annotation: Key of the annotation to update.
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:param future: Value of the annotation to update.
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"""
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future_result = future.result()
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if not future_result:
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return
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patch_headers = {
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'Content-Type': 'application/strategic-merge-patch+json',
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'Accept': 'application/json',
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}
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# Annotations are supposed to be key=value, being 'value'
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# an string. So we need to dump the dict result into the annotation into
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# a json
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future_result_json = jsonutils.dumps(future_result)
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annotations = {annotation: jsonutils.dumps(future_result)}
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data = jsonutils.dumps({
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'metadata': {
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'annotations': annotations}})
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url = self._k8s_root + self_link
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# TODO(devvesa): Use the aio package to convert this call into an
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# asynchornous one. Aio package does not support patch method yet.
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result = requests.patch(url, data=data, headers=patch_headers)
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if not result.ok:
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LOG.warn(_LW("PATCH request to %(url)s for annotation update "
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"%(data)s failed with error code %(error_code)s and "
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"reason %(reason)s"),
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{'url': url,
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'data': data,
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'error_code': result.status_code,
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'reason': result.json()})
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LOG.debug("Annotation update %(data)s succeded on resource %(url)s",
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{'data': data, 'url': url})
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async def _on_event(self, event):
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if not 'type' in event:
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LOG.warn(_LW('Received an event without "type":\n\n\t%(event)s'),
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{'event': event})
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return
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event_type = event['type']
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self_link = event['object']['metadata']['selfLink']
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LOG.info(_LI('Received an %(event_type)s event on a '
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'%(kind)s with link "%(link)s"'),
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{'event_type': event_type,
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'kind': event['object']['kind'],
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'link': self_link})
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# Dispatch the event on its method
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dispatch_map = {
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ADDED_EVENT: 'on_add',
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DELETED_EVENT: 'on_delete',
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MODIFIED_EVENT: 'on_modify'}
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if not event_type in dispatch_map:
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LOG.warning(_LW("Unhandled event type '%(event_type)s'"),
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{'event_type': event_type})
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return
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# Run the method on each of the translators defined on the config_map
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tasks = []
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for t_class in self._translators:
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translator = t_class()
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method = getattr(translator, dispatch_map[event_type])
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task = self._event_loop.create_task(method(event))
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task.add_done_callback(
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functools.partial(self._update_annotation, self_link,
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translator.get_annotation()))
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tasks.append(task)
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asyncio.wait(tasks)
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@property
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def api_endpoint(self):
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k8s_root = config.CONF.kubernetes.api_root
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return k8s_root + self.get_api_endpoint() + "?watch=true"
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@abc.abstractmethod
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def get_api_endpoint(self):
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pass
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async def watch(self):
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"""Watches the endpoint and calls the callback with its response.
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This is an endless task that keeps the event loop running forever
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"""
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connection = await self._get_chunked_connection()
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while True:
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content = await connection.read_line()
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LOG.debug('Received new event from %(watcher)s:\n\n\t'
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'%(event)s.\n\n',
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{'watcher': self.__class__.__name__,
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'event': str(content)})
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await self._on_event(content)
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class PodWatcher(AbstractBaseWatcher):
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"""Watch the Pod endpoints on K8s API."""
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ENDPOINT = "/api/v1/pods"
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def __init__(self, event_loop, translators):
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super().__init__(event_loop, translators)
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def get_api_endpoint(self):
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return self.ENDPOINT
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@ -1,123 +0,0 @@
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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
|
||||
# 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
|
||||
# under the License.
|
||||
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import abc
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import requests
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from kuryr.lib._i18n import _LE
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from oslo_log import log as logging
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from kuryr_kubernetes.aio import headers as aio_headers
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from kuryr_kubernetes.aio import methods as aio_methods
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from kuryr_kubernetes import config
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from kuryr_kubernetes import utils
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LOG = logging.getLogger(__name__)
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ADDED_EVENT = 'ADDED'
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DELETED_EVENT = 'DELETED'
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MODIFIED_EVENT = 'MODIFIED'
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class AbstractBaseWatcher(object):
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"""Base abstract watcher.
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This class implements the default interface for the KuryrK8sService task
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scheduler, which is the `watch` (no parameters) interface.
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It also define a serie of abstract methods that actual watchers have to
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implement in order to deal directly with events without worrying about
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connection and serialization details.
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These methods are:
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* get_endpoint(self): return a resource URL exposed on Kubernetes API
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as a string (such as "/api/v1/pods")
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* on_add/on_modify/on_delete: actions to do according to each event
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type.
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These methods have to follow the async/await python3.5 syntax
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"""
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def __init__(self, event_loop):
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self._event_loop = event_loop
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@abc.abstractmethod
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def get_api_endpoint(self):
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pass
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@property
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def api_endpoint(self):
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k8s_root = config.CONF.kubernetes.api_root
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return k8s_root + self.get_api_endpoint() + "?watch=true"
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async def _on_event(self, event): # flake8: noqa
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event_type = event['type']
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if event_type == ADDED_EVENT:
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await self.on_add(event)
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elif event_type == DELETED_EVENT:
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await self.on_delete(event)
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elif event_type == MODIFIED_EVENT:
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await self.on_modify(event)
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else:
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LOG.warning(_LW("Unhandled event type '%(event_type)s'"),
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{'event_type': event})
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|
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@abc.abstractmethod
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async def on_add(self, event):
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pass
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@abc.abstractmethod
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async def on_modify(self, event):
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pass
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@abc.abstractmethod
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async def on_delete(self, event):
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pass
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async def watch(self):
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"""Watches the endpoint and calls the callback with its response.
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|
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This is an endless task that keeps the event loop running forever
|
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"""
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response = await self._get_chunked_response()
|
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while True:
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content = await response.read_line()
|
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LOG.debug('Received new event from %(watcher)s:\n\n\t'
|
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'%(event)s.\n\n',
|
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{'watcher': self.__class__.__name__,
|
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'event': str(content)})
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await self._on_event(content)
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async def _get_chunked_response(self):
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"""Get the response from Kubernetes API."""
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response = await aio_methods.get(
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endpoint=self.api_endpoint,
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loop=self._event_loop,
|
||||
decoder=utils.utf8_json_decoder)
|
||||
|
||||
status, reason, hdrs = await response.read_headers()
|
||||
if status != requests.codes.ok: # Function returns 200
|
||||
LOG.error(_LE('GET request to endpoint %(ep)s failed with '
|
||||
'status %(status)s and reason %(reason)s'),
|
||||
{'ep': endpoint, 'status': status, 'reason': reason})
|
||||
raise requests.exceptions.HTTPError('{}: {}. Endpoint {}'.format(
|
||||
status, reason, endpoint))
|
||||
if hdrs.get(aio_headers.TRANSFER_ENCODING) != 'chunked':
|
||||
LOG.error(_LE('watcher GET request to endpoint %(ep)s is not '
|
||||
'chunked. headers: %(hdrs)s'),
|
||||
{'ep': endpoint, 'hdrs': hdrs})
|
||||
raise IOError(_('Can only watch endpoints that returned chunked '
|
||||
'encoded transfers'))
|
||||
|
||||
return response
|
||||
Loading…
Reference in New Issue