# 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.

from nova.tests.functional import integrated_helpers


class FinishResizeErrorAllocationCleanupTestCase(
        integrated_helpers.ProviderUsageBaseTestCase):
    """Test for bug 1825537 introduced in Rocky and backported down to Pike.

    Tests a scenario where finish_resize fails on the dest compute during a
    resize and ensures resource provider allocations are properly cleaned up
    in placement.
    """

    compute_driver = 'fake.FakeFinishMigrationFailDriver'

    def setUp(self):
        super(FinishResizeErrorAllocationCleanupTestCase, self).setUp()
        # Get the flavors we're going to use.
        flavors = self.api.get_flavors()
        self.flavor1 = flavors[0]
        self.flavor2 = flavors[1]

    def _resize_and_assert_error(self, server, dest_host):
        # Now resize the server and wait for it to go to ERROR status because
        # the finish_migration virt driver method in host2 should fail.
        req = {'resize': {'flavorRef': self.flavor2['id']}}
        self.api.post_server_action(server['id'], req)
        # The instance is set to ERROR status before the fault is recorded so
        # to avoid a race we need to wait for the task_state to change
        # to None which happens after the fault is recorded.
        server = self._wait_for_server_parameter(
            self.admin_api, server,
            {'status': 'ERROR', 'OS-EXT-STS:task_state': None})
        # The server should be pointing at $dest_host because resize_instance
        # will have updated the host/node value on the instance before casting
        # to the finish_resize method on the dest compute.
        self.assertEqual(dest_host, server['OS-EXT-SRV-ATTR:host'])
        # In this case the FakeFinishMigrationFailDriver.finish_migration
        # method raises VirtualInterfaceCreateException.
        self.assertIn('Virtual Interface creation failed',
                      server['fault']['message'])

    def test_finish_resize_fails_allocation_cleanup(self):
        # Start two computes so we can resize across hosts.
        self._start_compute('host1')
        self._start_compute('host2')

        # Create a server on host1.
        server = self._boot_and_check_allocations(self.flavor1, 'host1')

        # Resize to host2 which should fail.
        self._resize_and_assert_error(server, 'host2')

        # Check the resource provider allocations. Since the server is pointed
        # at the dest host in the DB now, the dest node resource provider
        # allocations should still exist with the new flavor.
        source_rp_uuid = self._get_provider_uuid_by_host('host1')
        dest_rp_uuid = self._get_provider_uuid_by_host('host2')
        # FIXME(mriedem): This is bug 1825537 where the allocations are
        # reverted when finish_resize fails so the dest node resource provider
        # does not have any allocations and the instance allocations are for
        # the old flavor on the source node resource provider even though the
        # instance is not running on the source host nor pointed at the source
        # host in the DB.
        # self.assertFlavorMatchesAllocation(
        #     self.flavor2, server['id'], dest_rp_uuid)
        dest_rp_usages = self._get_provider_usages(dest_rp_uuid)
        no_usage = {'VCPU': 0, 'MEMORY_MB': 0, 'DISK_GB': 0}
        self.assertEqual(no_usage, dest_rp_usages)
        source_usages = self._get_provider_usages(source_rp_uuid)
        self.assertFlavorMatchesAllocation(self.flavor1, source_usages)