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# Copyright (c) 2012 OpenStack Foundation
# 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.
"""Availability zone helper functions."""
from oslo.config import cfg
from nova import db
from nova.openstack.common import memorycache
# NOTE(vish): azs don't change that often, so cache them for an hour to
# avoid hitting the db multiple times on every request.
AZ_CACHE_SECONDS = 60 * 60
MC = None
availability_zone_opts = [
cfg.StrOpt('internal_service_availability_zone',
default='internal',
help='availability_zone to show internal services under'),
cfg.StrOpt('default_availability_zone',
default='nova',
help='default compute node availability_zone'),
]
CONF = cfg.CONF
CONF.register_opts(availability_zone_opts)
def _get_cache():
global MC
if MC is None:
MC = memorycache.get_client()
return MC
def _reset_cache():
"""Reset the cache, mainly for testing purposes."""
global MC
MC = None
def _make_cache_key(host):
return "azcache-%s" % host
def set_availability_zones(context, services):
# Makes sure services isn't a sqlalchemy object
services = [dict(service.iteritems()) for service in services]
metadata = db.aggregate_host_get_by_metadata_key(context,
key='availability_zone')
for service in services:
az = CONF.internal_service_availability_zone
if service['topic'] == "compute":
if metadata.get(service['host']):
az = u','.join(list(metadata[service['host']]))
else:
az = CONF.default_availability_zone
# update the cache
cache = _get_cache()
cache_key = _make_cache_key(service['host'])
cache.delete(cache_key)
cache.set(cache_key, az, AZ_CACHE_SECONDS)
service['availability_zone'] = az
return services
def get_host_availability_zone(context, host, conductor_api=None):
if conductor_api:
metadata = conductor_api.aggregate_metadata_get_by_host(
context, host, key='availability_zone')
else:
metadata = db.aggregate_metadata_get_by_host(
context, host, key='availability_zone')
if 'availability_zone' in metadata:
az = list(metadata['availability_zone'])[0]
else:
az = CONF.default_availability_zone
return az
def get_availability_zones(context):
"""Return available and unavailable zones."""
enabled_services = db.service_get_all(context, False)
disabled_services = db.service_get_all(context, True)
enabled_services = set_availability_zones(context, enabled_services)
disabled_services = set_availability_zones(context, disabled_services)
available_zones = []
for zone in [service['availability_zone'] for service
in enabled_services]:
if zone not in available_zones:
available_zones.append(zone)
not_available_zones = []
zones = [service['availability_zone'] for service in disabled_services
if service['availability_zone'] not in available_zones]
for zone in zones:
if zone not in not_available_zones:
not_available_zones.append(zone)
return (available_zones, not_available_zones)
def get_instance_availability_zone(context, instance):
"""Return availability zone of specified instance."""
host = str(instance.get('host'))
if not host:
return None
cache_key = _make_cache_key(host)
cache = _get_cache()
az = cache.get(cache_key)
if not az:
elevated = context.elevated()
az = get_host_availability_zone(elevated, host)
cache.set(cache_key, az, AZ_CACHE_SECONDS)
return az
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