Use an inner join on aggregate_hosts in aggregate_get_by_host

Fixes bug 1187708

By default, sqlalchemy.orm.joinedload does a left outer join.  But in
aggregate_get_by_host, we only want to get aggregates rows with
aggregate_hosts rows that match the host, and a left outer join also
gave us aggregates rows with no matching aggregate_hosts row.

Also improve test_aggregate_get_by_host to catch this bug.

Change-Id: Ida9647af02ab58229abe3c50dc3d2c7ec9792a5e

nova/db/sqlalchemy/api.py

@@ -4614,12 +4614,19 @@ def aggregate_get(context, aggregate_id):
 
 @require_admin_context
 def aggregate_get_by_host(context, host, key=None):
-    query = _aggregate_get_query(context, models.Aggregate,
-            models.AggregateHost.host, host)
+    """Return rows that match host (mandatory) and metadata key (optional).
+
+    :param host matches host, and is required.
+    :param key Matches metadata key, if not None.
+    """
+    query = model_query(context, models.Aggregate)
+    query = query.options(joinedload('_hosts', innerjoin=True))
+    query = query.options(joinedload('_metadata'))
+    query = query.filter(models.AggregateHost.host == host)
 
     if key:
         query = query.join("_metadata").filter(
-        models.AggregateMetadata.key == key)
+            models.AggregateMetadata.key == key)
     return query.all()
 
 

nova/tests/db/test_db_api.py

@@ -1435,17 +1435,22 @@ def test_aggregate_get(self):
     def test_aggregate_get_by_host(self):
         ctxt = context.get_admin_context()
         values = {'name': 'fake_aggregate2'}
+        values2 = {'name': 'fake_aggregate4'}
         a1 = _create_aggregate_with_hosts(context=ctxt)
         a2 = _create_aggregate_with_hosts(context=ctxt, values=values)
+        # a3 has no hosts and should not be in the results.
+        a3 = _create_aggregate(context=ctxt, values=values2)
         r1 = db.aggregate_get_by_host(ctxt, 'foo.openstack.org')
         self.assertEqual([a1['id'], a2['id']], [x['id'] for x in r1])
 
     def test_aggregate_get_by_host_with_key(self):
         ctxt = context.get_admin_context()
         values = {'name': 'fake_aggregate2'}
+        values2 = {'name': 'fake_aggregate4'}
         a1 = _create_aggregate_with_hosts(context=ctxt,
                                           metadata={'goodkey': 'good'})
         a2 = _create_aggregate_with_hosts(context=ctxt, values=values)
+        a3 = _create_aggregate(context=ctxt, values=values2)
         # filter result by key
         r1 = db.aggregate_get_by_host(ctxt, 'foo.openstack.org', key='goodkey')
         self.assertEqual([a1['id']], [x['id'] for x in r1])