Add service supervisor
This patch set adds supervisor mechanism for Watcher services to get ability to track states. Partially-Implements: blueprint watcher-service-list Change-Id: Iab1cefb971c79ed27b22b6a5d1bed8698e35f9a4
This commit is contained in:
Alexander Chadin
263
watcher/api/controllers/v1/service.py
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263
watcher/api/controllers/v1/service.py
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# -*- encoding: utf-8 -*-
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# Copyright (c) 2016 Servionica
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain 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,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
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# implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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"""
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Service mechanism provides ability to monitor Watcher services state.
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"""
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import datetime
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import six
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from oslo_config import cfg
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from oslo_log import log
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from oslo_utils import timeutils
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import pecan
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from pecan import rest
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import wsme
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from wsme import types as wtypes
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import wsmeext.pecan as wsme_pecan
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from watcher._i18n import _LW
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from watcher.api.controllers import base
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from watcher.api.controllers import link
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from watcher.api.controllers.v1 import collection
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from watcher.api.controllers.v1 import utils as api_utils
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from watcher.common import exception
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from watcher.common import policy
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from watcher import objects
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CONF = cfg.CONF
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LOG = log.getLogger(__name__)
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class Service(base.APIBase):
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"""API representation of a service.
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This class enforces type checking and value constraints, and converts
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between the internal object model and the API representation of a service.
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"""
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_status = None
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def _get_status(self):
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return self._status
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def _set_status(self, name):
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service = objects.Service.get_by_name(pecan.request.context, name)
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last_heartbeat = (service.last_seen_up or service.updated_at
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or service.created_at)
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if isinstance(last_heartbeat, six.string_types):
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# NOTE(russellb) If this service came in over rpc via
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# conductor, then the timestamp will be a string and needs to be
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# converted back to a datetime.
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last_heartbeat = timeutils.parse_strtime(last_heartbeat)
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else:
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# Objects have proper UTC timezones, but the timeutils comparison
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# below does not (and will fail)
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last_heartbeat = last_heartbeat.replace(tzinfo=None)
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elapsed = timeutils.delta_seconds(last_heartbeat, timeutils.utcnow())
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is_up = abs(elapsed) <= CONF.service_down_time
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if not is_up:
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LOG.warning(_LW('Seems service %(name)s on host %(host)s is down. '
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'Last heartbeat was %(lhb)s.'
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'Elapsed time is %(el)s'),
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{'name': service.name,
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'host': service.host,
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'lhb': str(last_heartbeat), 'el': str(elapsed)})
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self._status = objects.service.ServiceStatus.FAILED
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else:
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self._status = objects.service.ServiceStatus.ACTIVE
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id = wsme.wsattr(int, readonly=True)
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"""ID for this service."""
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name = wtypes.text
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"""Name of the service."""
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host = wtypes.text
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"""Host where service is placed on."""
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last_seen_up = wsme.wsattr(datetime.datetime, readonly=True)
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"""Time when Watcher service sent latest heartbeat."""
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status = wsme.wsproperty(wtypes.text, _get_status, _set_status,
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mandatory=True)
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links = wsme.wsattr([link.Link], readonly=True)
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"""A list containing a self link."""
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def __init__(self, **kwargs):
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super(Service, self).__init__()
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fields = list(objects.Service.fields.keys()) + ['status']
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self.fields = []
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for field in fields:
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self.fields.append(field)
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setattr(self, field, kwargs.get(
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field if field != 'status' else 'name', wtypes.Unset))
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@staticmethod
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def _convert_with_links(service, url, expand=True):
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if not expand:
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service.unset_fields_except(
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['id', 'name', 'host', 'status'])
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service.links = [
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link.Link.make_link('self', url, 'services', str(service.id)),
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link.Link.make_link('bookmark', url, 'services', str(service.id),
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bookmark=True)]
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return service
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@classmethod
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def convert_with_links(cls, service, expand=True):
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service = Service(**service.as_dict())
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return cls._convert_with_links(
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service, pecan.request.host_url, expand)
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@classmethod
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def sample(cls, expand=True):
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sample = cls(id=1,
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name='watcher-applier',
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host='Controller',
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last_seen_up=datetime.datetime(2016, 1, 1))
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return cls._convert_with_links(sample, 'http://localhost:9322', expand)
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class ServiceCollection(collection.Collection):
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"""API representation of a collection of services."""
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services = [Service]
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"""A list containing services objects"""
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def __init__(self, **kwargs):
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super(ServiceCollection, self).__init__()
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self._type = 'services'
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@staticmethod
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def convert_with_links(services, limit, url=None, expand=False,
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**kwargs):
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service_collection = ServiceCollection()
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service_collection.services = [
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Service.convert_with_links(g, expand) for g in services]
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if 'sort_key' in kwargs:
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reverse = False
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if kwargs['sort_key'] == 'service':
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if 'sort_dir' in kwargs:
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reverse = True if kwargs['sort_dir'] == 'desc' else False
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service_collection.services = sorted(
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service_collection.services,
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key=lambda service: service.id,
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reverse=reverse)
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service_collection.next = service_collection.get_next(
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limit, url=url, marker_field='id', **kwargs)
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return service_collection
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@classmethod
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def sample(cls):
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sample = cls()
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sample.services = [Service.sample(expand=False)]
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return sample
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class ServicesController(rest.RestController):
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"""REST controller for Services."""
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def __init__(self):
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super(ServicesController, self).__init__()
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from_services = False
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"""A flag to indicate if the requests to this controller are coming
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from the top-level resource Services."""
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_custom_actions = {
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'detail': ['GET'],
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}
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def _get_services_collection(self, marker, limit, sort_key, sort_dir,
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expand=False, resource_url=None):
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limit = api_utils.validate_limit(limit)
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api_utils.validate_sort_dir(sort_dir)
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sort_db_key = (sort_key if sort_key in objects.Service.fields.keys()
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else None)
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marker_obj = None
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if marker:
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marker_obj = objects.Service.get(
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pecan.request.context, marker)
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services = objects.Service.list(
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pecan.request.context, limit, marker_obj,
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sort_key=sort_db_key, sort_dir=sort_dir)
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return ServiceCollection.convert_with_links(
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services, limit, url=resource_url, expand=expand,
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sort_key=sort_key, sort_dir=sort_dir)
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@wsme_pecan.wsexpose(ServiceCollection, int, int, wtypes.text, wtypes.text)
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def get_all(self, marker=None, limit=None, sort_key='id', sort_dir='asc'):
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"""Retrieve a list of services.
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:param marker: pagination marker for large data sets.
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:param limit: maximum number of resources to return in a single result.
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:param sort_key: column to sort results by. Default: id.
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:param sort_dir: direction to sort. "asc" or "desc". Default: asc.
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"""
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context = pecan.request.context
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policy.enforce(context, 'service:get_all',
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action='service:get_all')
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return self._get_services_collection(marker, limit, sort_key, sort_dir)
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@wsme_pecan.wsexpose(ServiceCollection, int, int, wtypes.text, wtypes.text)
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def detail(self, marker=None, limit=None, sort_key='id', sort_dir='asc'):
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"""Retrieve a list of services with detail.
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:param marker: pagination marker for large data sets.
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:param limit: maximum number of resources to return in a single result.
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:param sort_key: column to sort results by. Default: id.
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:param sort_dir: direction to sort. "asc" or "desc". Default: asc.
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"""
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context = pecan.request.context
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policy.enforce(context, 'service:detail',
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action='service:detail')
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# NOTE(lucasagomes): /detail should only work agaist collections
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parent = pecan.request.path.split('/')[:-1][-1]
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if parent != "services":
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raise exception.HTTPNotFound
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expand = True
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resource_url = '/'.join(['services', 'detail'])
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return self._get_services_collection(
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marker, limit, sort_key, sort_dir, expand, resource_url)
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@wsme_pecan.wsexpose(Service, wtypes.text)
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def get_one(self, service):
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"""Retrieve information about the given service.
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:param service: ID or name of the service.
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"""
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if self.from_services:
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raise exception.OperationNotPermitted
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context = pecan.request.context
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rpc_service = api_utils.get_resource('Service', service)
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policy.enforce(context, 'service:get', rpc_service,
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action='service:get')
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return Service.convert_with_links(rpc_service)
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