# Copyright (c) 2010 OpenStack Foundation
# Copyright 2010 United States Government as represented by the
# Administrator of the National Aeronautics and Space Administration.
# 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.

"""
Scheduler Service
"""

from oslo.config import cfg
from oslo import messaging

from nova.compute import rpcapi as compute_rpcapi
from nova.compute import task_states
from nova.compute import utils as compute_utils
from nova.compute import vm_states
from nova.conductor import api as conductor_api
from nova.conductor.tasks import live_migrate
from nova import exception
from nova import manager
from nova.objects import instance as instance_obj
from nova.openstack.common import excutils
from nova.openstack.common import importutils
from nova.openstack.common import jsonutils
from nova.openstack.common import log as logging
from nova.openstack.common import periodic_task
from nova import quota
from nova.scheduler import utils as scheduler_utils


LOG = logging.getLogger(__name__)

scheduler_driver_opts = [
    cfg.StrOpt('scheduler_driver',
               default='nova.scheduler.filter_scheduler.FilterScheduler',
               help='Default driver to use for the scheduler'),
    cfg.IntOpt('scheduler_driver_task_period',
               default=60,
               help='How often (in seconds) to run periodic tasks in '
                    'the scheduler driver of your choice. '
                    'Please note this is likely to interact with the value '
                    'of service_down_time, but exactly how they interact '
                    'will depend on your choice of scheduler driver.'),
]
CONF = cfg.CONF
CONF.register_opts(scheduler_driver_opts)

QUOTAS = quota.QUOTAS


class SchedulerManager(manager.Manager):
    """Chooses a host to run instances on."""

    target = messaging.Target(version='2.9')

    def __init__(self, scheduler_driver=None, *args, **kwargs):
        if not scheduler_driver:
            scheduler_driver = CONF.scheduler_driver
        self.driver = importutils.import_object(scheduler_driver)
        self.compute_rpcapi = compute_rpcapi.ComputeAPI()
        super(SchedulerManager, self).__init__(service_name='scheduler',
                                               *args, **kwargs)
        self.additional_endpoints.append(_SchedulerManagerV3Proxy(self))

    def create_volume(self, context, volume_id, snapshot_id,
                      reservations=None, image_id=None):
        #function removed in RPC API 2.3
        pass

    @messaging.expected_exceptions(exception.NoValidHost,
                                   exception.ComputeServiceUnavailable,
                                   exception.InvalidHypervisorType,
                                   exception.UnableToMigrateToSelf,
                                   exception.DestinationHypervisorTooOld,
                                   exception.InvalidLocalStorage,
                                   exception.InvalidSharedStorage,
                                   exception.MigrationPreCheckError)
    def live_migration(self, context, instance, dest,
                       block_migration, disk_over_commit, pclm):
        try:
            self._schedule_live_migration(context, instance, dest,
                    block_migration, disk_over_commit, pclm)
        except (exception.NoValidHost,
                exception.ComputeServiceUnavailable,
                exception.InvalidHypervisorType,
                exception.UnableToMigrateToSelf,
                exception.DestinationHypervisorTooOld,
                exception.InvalidLocalStorage,
                exception.InvalidSharedStorage,
                exception.MigrationPreCheckError) as ex:
            request_spec = {'instance_properties': {
                'uuid': instance['uuid'], },
            }
            with excutils.save_and_reraise_exception():
                self._set_vm_state_and_notify('live_migration',
                            dict(vm_state=instance['vm_state'],
                                 task_state=None,
                                 expected_task_state=task_states.MIGRATING,),
                                              context, ex, request_spec)
        except Exception as ex:
            request_spec = {'instance_properties': {
                'uuid': instance['uuid'], },
            }
            with excutils.save_and_reraise_exception():
                self._set_vm_state_and_notify('live_migration',
                                             {'vm_state': vm_states.ERROR},
                                             context, ex, request_spec)

    def _schedule_live_migration(self, context, instance, dest,
            block_migration, disk_over_commit, pclm):
        task = live_migrate.LiveMigrationTask(context, instance,
                    dest, block_migration, disk_over_commit, pclm)
        return task.execute()

    def run_instance(self, context, request_spec, admin_password,
            injected_files, requested_networks, is_first_time,
            filter_properties, legacy_bdm_in_spec=True):
        """Tries to call schedule_run_instance on the driver.
        Sets instance vm_state to ERROR on exceptions
        """
        instance_uuids = request_spec['instance_uuids']
        with compute_utils.EventReporter(context, conductor_api.LocalAPI(),
                                         'schedule', *instance_uuids):
            try:
                return self.driver.schedule_run_instance(context,