Add object and database support for host_status API

This is initial object and database support for the API discovering and
exposing the state of an instance's host.

Related to blueprint get-valid-server-state

Change-Id: Id6e59065bc2784d376d569591583d9572fc9597f
Co-Authored-By: Dan Smith <dansmith@redhat.com>

nova/db/sqlalchemy/models.py

@@ -103,6 +103,15 @@ class Service(BASE, NovaBase, models.SoftDeleteMixin):
     forced_down = Column(Boolean, default=False)
     version = Column(Integer, default=0)
 
+    instance = orm.relationship(
+        "Instance",
+        backref='services',
+        primaryjoin='and_(Service.host == Instance.host,'
+                    'Service.binary == "nova-compute",'
+                    'Instance.deleted == 0)',
+        foreign_keys=host,
+    )
+
 
 class ComputeNode(BASE, NovaBase, models.SoftDeleteMixin):
     """Represents a running compute service on a host."""

nova/objects/fields.py

@@ -420,6 +420,20 @@ class MonitorMetricType(Enum):
             valid_values=MonitorMetricType.ALL)
 
 
+class HostStatus(Enum):
+
+    UP = "UP"  # The nova-compute is up.
+    DOWN = "DOWN"  # The nova-compute is forced_down.
+    MAINTENANCE = "MAINTENANCE"  # The nova-compute is disabled.
+    UNKNOWN = "UNKNOWN"  # The nova-compute has not reported.
+
+    ALL = (UP, DOWN, MAINTENANCE, UNKNOWN)
+
+    def __init__(self):
+        super(HostStatus, self).__init__(
+            valid_values=HostStatus.ALL)
+
+
 class PciDeviceStatus(Enum):
 
     AVAILABLE = "available"

nova/objects/instance.py

@@ -19,6 +19,7 @@ from oslo_db import exception as db_exc
 from oslo_log import log as logging
 from oslo_serialization import jsonutils
 from oslo_utils import timeutils
+from oslo_utils import versionutils
 
 from nova.cells import opts as cells_opts
 from nova.cells import rpcapi as cells_rpcapi
@@ -40,7 +41,7 @@ LOG = logging.getLogger(__name__)
 # List of fields that can be joined in DB layer.
 _INSTANCE_OPTIONAL_JOINED_FIELDS = ['metadata', 'system_metadata',
                                     'info_cache', 'security_groups',
-                                    'pci_devices', 'tags']
+                                    'pci_devices', 'tags', 'services']
 # These are fields that are optional but don't translate to db columns
 _INSTANCE_OPTIONAL_NON_COLUMN_FIELDS = ['fault', 'flavor', 'old_flavor',
                                         'new_flavor', 'ec2_ids']
@@ -86,7 +87,8 @@ _NO_DATA_SENTINEL = object()
 class Instance(base.NovaPersistentObject, base.NovaObject,
                base.NovaObjectDictCompat):
     # Version 2.0: Initial version
-    VERSION = '2.0'
+    # Version 2.1: Added services
+    VERSION = '2.1'
 
     fields = {
         'id': fields.IntegerField(),
@@ -107,6 +109,8 @@ class Instance(base.NovaPersistentObject, base.NovaObject,
         'vm_state': fields.StringField(nullable=True),
         'task_state': fields.StringField(nullable=True),
 
+        'services': fields.ObjectField('ServiceList'),
+
         'memory_mb': fields.IntegerField(nullable=True),
         'vcpus': fields.IntegerField(nullable=True),
         'root_gb': fields.IntegerField(nullable=True),
@@ -187,6 +191,12 @@ class Instance(base.NovaPersistentObject, base.NovaObject,
 
     obj_extra_fields = ['name']
 
+    def obj_make_compatible(self, primitive, target_version):
+        super(Instance, self).obj_make_compatible(primitive, target_version)
+        target_version = versionutils.convert_version_to_tuple(target_version)
+        if target_version < (2, 1) and 'services' in primitive:
+            del primitive['services']
+
     def __init__(self, *args, **kwargs):
         super(Instance, self).__init__(*args, **kwargs)
         self._reset_metadata_tracking()
@@ -360,6 +370,12 @@ class Instance(base.NovaPersistentObject, base.NovaObject,
                 objects.Tag, db_inst['tags'])
             instance['tags'] = tags
 
+        if 'services' in expected_attrs:
+            services = base.obj_make_list(
+                    context, objects.ServiceList(context),
+                    objects.Service, db_inst['services'])
+            instance['services'] = services
+
         instance.obj_reset_changes()
         return instance
 

nova/tests/unit/fake_instance.py

@@ -74,7 +74,8 @@ def fake_db_instance(**updates):
                   'numa_topology': None,
                   'vcpu_model': None,
                  },
-        'tags': []
+        'tags': [],
+        'services': []
         }
 
     for name, field in objects.Instance.fields.items():

nova/tests/unit/objects/test_instance.py

@@ -153,7 +153,16 @@ class _TestInstanceObject(object):
             test_vcpu_model.fake_vcpumodel.obj_to_primitive())
         fake_mig_context = jsonutils.dumps(
             test_mig_ctxt.fake_migration_context_obj.obj_to_primitive())
+        fake_service = {'created_at': None, 'updated_at': None,
+                        'deleted_at': None, 'deleted': False, 'id': 123,
+                        'host': 'fake-host', 'binary': 'nova-fake',
+                        'topic': 'fake-service-topic', 'report_count': 1,
+                        'forced_down': False, 'disabled': False,
+                        'disabled_reason': None, 'last_seen_up': None,
+                        'version': 1,
+                    }
         fake_instance = dict(self.fake_instance,
+                             services=[fake_service],
                              extra={
                                  'numa_topology': fake_topology,
                                  'pci_requests': fake_requests,
@@ -177,6 +186,7 @@ class _TestInstanceObject(object):
             expected_attrs=instance.INSTANCE_OPTIONAL_ATTRS)
         for attr in instance.INSTANCE_OPTIONAL_ATTRS:
             self.assertTrue(inst.obj_attr_is_set(attr))
+        self.assertEqual(123, inst.services[0].id)
 
     def test_get_by_id(self):
         self.mox.StubOutWithMock(db, 'instance_get')

nova/tests/unit/objects/test_objects.py

@@ -1134,7 +1134,7 @@ object_data = {
     'HVSpec': '1.2-db672e73304da86139086d003f3977e7',
     'ImageMeta': '1.8-642d1b2eb3e880a367f37d72dd76162d',
     'ImageMetaProps': '1.11-96aa14a8ba226701bbd22e63557a63ea',
-    'Instance': '2.0-ff56804dce87d81d9a04834d4bd1e3d2',
+    'Instance': '2.1-416fdd0dfc33dfa12ff2cfdd8cc32e17',
     'InstanceAction': '1.1-f9f293e526b66fca0d05c3b3a2d13914',
     'InstanceActionEvent': '1.1-e56a64fa4710e43ef7af2ad9d6028b33',
     'InstanceActionEventList': '1.1-13d92fb953030cdbfee56481756e02be',