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OpenStack Study: availability_zones.py**** CubicPower OpenStack Study **** def _get_cache(): global MC if MC is None: MC = memorycache.get_client() return MC
**** CubicPower OpenStack Study **** def reset_cache(): """Reset the cache, mainly for testing purposes and update availability_zone for host aggregate """ global MC MC = None
**** CubicPower OpenStack Study **** def _make_cache_key(host): return "azcache-%s" % host.encode('utf-8')
**** CubicPower OpenStack Study **** 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 update_host_availability_zone_cache(context, service['host'], az) service['availability_zone'] = az return services
**** CubicPower OpenStack Study **** 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
**** CubicPower OpenStack Study **** def update_host_availability_zone_cache(context, host, availability_zone=None): if not availability_zone: availability_zone = get_host_availability_zone(context, host) cache = _get_cache() cache_key = _make_cache_key(host) cache.delete(cache_key) cache.set(cache_key, availability_zone, AZ_CACHE_SECONDS)
**** CubicPower OpenStack Study **** def get_availability_zones(context, get_only_available=False): """Return available and unavailable zones on demand. :param get_only_available: flag to determine whether to return available zones only, default False indicates return both available zones and not available zones, True indicates return available zones only """ enabled_services = db.service_get_all(context, False) enabled_services = set_availability_zones(context, enabled_services) available_zones = [] for zone in [service['availability_zone'] for service in enabled_services]: if zone not in available_zones: available_zones.append(zone) if not get_only_available: disabled_services = db.service_get_all(context, True) disabled_services = set_availability_zones(context, disabled_services) 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) else: return available_zones
**** CubicPower OpenStack Study **** 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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