# Copyright 2011 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.
"""
Tests For Filter Scheduler.
"""

import mock

from nova import exception
from nova import objects
from nova.scheduler import filter_scheduler
from nova.scheduler import host_manager
from nova.scheduler import utils as scheduler_utils
from nova.scheduler import weights
from nova import test  # noqa
from nova.tests.unit.scheduler import fakes
from nova.tests.unit.scheduler import test_scheduler


def fake_get_filtered_hosts(hosts, filter_properties, index):
    return list(hosts)


class FilterSchedulerTestCase(test_scheduler.SchedulerTestCase):
    """Test case for Filter Scheduler."""

    driver_cls = filter_scheduler.FilterScheduler

    @mock.patch('nova.objects.ServiceList.get_by_binary',
                return_value=fakes.SERVICES)
    @mock.patch('nova.objects.InstanceList.get_by_host')
    @mock.patch('nova.objects.ComputeNodeList.get_all',
                return_value=fakes.COMPUTE_NODES)
    @mock.patch('nova.db.instance_extra_get_by_instance_uuid',
                return_value={'numa_topology': None,
                              'pci_requests': None})
    def test_schedule_happy_day(self, mock_get_extra, mock_get_all,
                                mock_by_host, mock_get_by_binary):
        """Make sure there's nothing glaringly wrong with _schedule()
        by doing a happy day pass through.
        """

        self.next_weight = 1.0

        def _fake_weigh_objects(_self, functions, hosts, options):
            self.next_weight += 2.0
            host_state = hosts[0]
            return [weights.WeighedHost(host_state, self.next_weight)]

        self.stub_out('nova.scheduler.weights.HostWeightHandler.'
                'get_weighed_objects', _fake_weigh_objects)

        spec_obj = objects.RequestSpec(
            num_instances=10,
            flavor=objects.Flavor(memory_mb=512,
                                  root_gb=512,
                                  ephemeral_gb=0,
                                  vcpus=1),
            project_id=1,
            os_type='Linux',
            uuid='fake-uuid',
            pci_requests=None,
            numa_topology=None,
            instance_group=None)

        with mock.patch.object(self.driver.host_manager,
                               'get_filtered_hosts') as mock_get_hosts:
            mock_get_hosts.side_effect = fake_get_filtered_hosts
            weighed_hosts = self.driver._schedule(self.context, spec_obj)

        self.assertEqual(len(weighed_hosts), 10)
        for weighed_host in weighed_hosts:
            self.assertIsNotNone(weighed_host.obj)

    def test_add_retry_host(self):
        retry = dict(num_attempts=1, hosts=[])
        filter_properties = dict(retry=retry)
        host = "fakehost"
        node = "fakenode"

        scheduler_utils._add_retry_host(filter_properties, host, node)

        hosts = filter_properties['retry']['hosts']
        self.assertEqual(1, len(hosts))
        self.assertEqual([host, node], hosts[0])

    def test_post_select_populate(self):
        # Test addition of certain filter props after a node is selected.
        retry = {'hosts': [], 'num_attempts': 1}
        filter_properties = {'retry': retry}

        host_state = host_manager.HostState('host', 'node')
        host_state.limits['vcpu'] = 5
        scheduler_utils.populate_filter_properties(filter_properties,
                host_state)

        self.assertEqual(['host', 'node'],
                         filter_properties['retry']['hosts'][0])

        self.assertEqual({'vcpu': 5}, host_state.limits)

    @mock.patch('nova.objects.ServiceList.get_by_binary',
                return_value=fakes.SERVICES)
    @mock.patch('nova.objects.InstanceList.get_by_host')
    @mock.patch('nova.objects.ComputeNodeList.get_all',
                return_value=fakes.COMPUTE_NODES)
    @mock.patch('nova.db.instance_extra_get_by_instance_uuid',
                return_value={'numa_topology': None,
                              'pci_requests': None})
    def test_schedule_host_pool(self, mock_get_extra, mock_get_all,
                                mock_by_host, mock_get_by_binary):
        """Make sure the scheduler_host_subset_size property works properly."""

        self.flags(scheduler_host_subset_size=2)

        spec_obj = objects.RequestSpec(
            num_instances=1,
            project_id=1,
            os_type='Linux',
            uuid='fake-uuid',
            flavor=objects.Flavor(root_gb=512,
                                  memory_mb=512,
                                  ephemeral_gb=0,
                                  vcpus=1),
            pci_requests=None,
            numa_topology=None,
            instance_group=None)

        with mock.patch.object(self.driver.host_manager,
                               'get_filtered_hosts') as mock_get_hosts:
            mock_get_hosts.side_effect = fake_get_filtered_hosts
            hosts = self.driver._schedule(self.context, spec_obj)

        # one host should be chosen
        self.assertEqual(len(hosts), 1)

    @mock.patch('nova.objects.ServiceList.get_by_binary',
                return_value=fakes.SERVICES)
    @mock.patch('nova.objects.InstanceList.get_by_host')
    @mock.patch('nova.objects.ComputeNodeList.get_all',
                return_value=fakes.COMPUTE_NODES)
    @mock.patch('nova.db.instance_extra_get_by_instance_uuid',
                return_value={'numa_topology': None,
                              'pci_requests': None})
    def test_schedule_large_host_pool(self, mock_get_extra, mock_get_all,
                                      mock_by_host, mock_get_by_binary):
        """Hosts should still be chosen if pool size
        is larger than number of filtered hosts.
        """

        self.flags(scheduler_host_subset_size=20)

        spec_obj = objects.RequestSpec(
            num_instances=1,
            project_id=1,
            os_type='Linux',
            uuid='fake-uuid',
            flavor=objects.Flavor(root_gb=512,
                                  memory_mb=512,
                                  ephemeral_gb=0,
                                  vcpus=1),
            pci_requests=None,
            numa_topology=None,
            instance_group=None)

        with mock.patch.object(self.driver.host_manager,
                               'get_filtered_hosts') as mock_get_hosts:
            mock_get_hosts.side_effect = fake_get_filtered_hosts
            hosts = self.driver._schedule(self.context, spec_obj)

        # one host should be chosen
        self.assertEqual(len(hosts), 1)

    @mock.patch('nova.scheduler.host_manager.HostManager._get_instance_info')
    @mock.patch('nova.objects.ServiceList.get_by_binary',
                return_value=fakes.SERVICES)
    @mock.patch('nova.objects.ComputeNodeList.get_all',
                return_value=fakes.COMPUTE_NODES)
    @mock.patch('nova.db.instance_extra_get_by_instance_uuid',
                return_value={'numa_topology': None,
                              'pci_requests': None})
    def test_schedule_chooses_best_host(self, mock_get_extra, mock_cn_get_all,
                                        mock_get_by_binary,
                                        mock_get_inst_info):
        """If scheduler_host_subset_size is 1, the largest host with greatest
        weight should be returned.
        """

        self.flags(scheduler_host_subset_size=1)
        self.next_weight = 50

        def _fake_weigh_objects(_self, functions, hosts, options):
            this_weight = self.next_weight
            self.next_weight = 0
            host_state = hosts[0]
            return [weights.WeighedHost(host_state, this_weight)]

        self.stub_out('nova.scheduler.weights.HostWeightHandler.'
                'get_weighed_objects', _fake_weigh_objects)

        spec_obj = objects.RequestSpec(
            num_instances=1,
            project_id=1,
            os_type='Linux',
            uuid='fake-uuid',
            flavor=objects.Flavor(root_gb=512,
                                  memory_mb=512,
                                  ephemeral_gb=0,
                                  vcpus=1),
            pci_requests=None,
            numa_topology=None,
            instance_group=None)

        with mock.patch.object(self.driver.host_manager,
                               'get_filtered_hosts') as mock_get_hosts:
            mock_get_hosts.side_effect = fake_get_filtered_hosts
            hosts = self.driver._schedule(self.context, spec_obj)

        # one host should be chosen
        self.assertEqual(1, len(hosts))

        self.assertEqual(50, hosts[0].weight)

    @mock.patch('nova.objects.ServiceList.get_by_binary',
                return_value=fakes.SERVICES)
    @mock.patch('nova.objects.InstanceList.get_by_host')
    @mock.patch('nova.objects.ComputeNodeList.get_all',
                return_value=fakes.COMPUTE_NODES)
    @mock.patch('nova.db.instance_extra_get_by_instance_uuid',
                return_value={'numa_topology': None,
                              'pci_requests': None})
    def test_select_destinations(self, mock_get_extra, mock_get_all,
                                 mock_by_host, mock_get_by_binary):
        """select_destinations is basically a wrapper around _schedule().

        Similar to the _schedule tests, this just does a happy path test to
        ensure there is nothing glaringly wrong.
        """

        self.next_weight = 1.0

        selected_hosts = []
        selected_nodes = []

        def _fake_weigh_objects(_self, functions, hosts, options):
            self.next_weight += 2.0
            host_state = hosts[0]
            selected_hosts.append(host_state.host)
            selected_nodes.append(host_state.nodename)
            return [weights.WeighedHost(host_state, self.next_weight)]

        self.stub_out('nova.scheduler.weights.HostWeightHandler.'
                'get_weighed_objects', _fake_weigh_objects)

        spec_obj = objects.RequestSpec(
            flavor=objects.Flavor(memory_mb=512,
                                  root_gb=512,
                                  ephemeral_gb=0,
                                  vcpus=1),
            project_id=1,
            os_type='Linux',
            instance_uuid='fake-uuid',
            num_instances=1,
            pci_requests=None,
            numa_topology=None,
            instance_group=None)

        with mock.patch.object(self.driver.host_manager,
                               'get_filtered_hosts') as mock_get_hosts:
            mock_get_hosts.side_effect = fake_get_filtered_hosts
            dests = self.driver.select_destinations(self.context, spec_obj)

        (host, node) = (dests[0]['host'], dests[0]['nodename'])
        self.assertEqual(host, selected_hosts[0])
        self.assertEqual(node, selected_nodes[0])

    @mock.patch.object(filter_scheduler.FilterScheduler, '_schedule')
    def test_select_destinations_notifications(self, mock_schedule):
        mock_schedule.return_value = [mock.Mock()]

        with mock.patch.object(self.driver.notifier, 'info') as mock_info:
            expected = {'num_instances': 1,
                        'instance_properties': {'uuid': 'uuid1'},
                        'instance_type': {},
                        'image': {}}
            spec_obj = objects.RequestSpec(num_instances=1,
                                           instance_uuid='uuid1')

            self.driver.select_destinations(self.context, spec_obj)

            expected = [
                mock.call(self.context, 'scheduler.select_destinations.start',
                 dict(request_spec=expected)),
                mock.call(self.context, 'scheduler.select_destinations.end',
                 dict(request_spec=expected))]
            self.assertEqual(expected, mock_info.call_args_list)

    @mock.patch.object(filter_scheduler.FilterScheduler, '_schedule')
    def test_select_destinations_no_valid_host(self, mock_schedule):
        mock_schedule.return_value = []
        self.assertRaises(exception.NoValidHost,
                self.driver.select_destinations, self.context,
                objects.RequestSpec(num_instances=1))

    def test_select_destinations_no_valid_host_not_enough(self):
        # Tests that we have fewer hosts available than number of instances
        # requested to build.
        consumed_hosts = [mock.MagicMock(), mock.MagicMock()]
        with mock.patch.object(self.driver, '_schedule',
                               return_value=consumed_hosts):
            try:
                self.driver.select_destinations(
                    self.context, objects.RequestSpec(num_instances=3))
                self.fail('Expected NoValidHost to be raised.')
            except exception.NoValidHost as e:
                # Make sure that we provided a reason why NoValidHost.
                self.assertIn('reason', e.kwargs)
                self.assertTrue(len(e.kwargs['reason']) > 0)
                # Make sure that the consumed hosts have chance to be reverted.
                for host in consumed_hosts:
                    self.assertIsNone(host.obj.updated)
