db: Don't use legacy calling style of select()

Resolve the following RemovedIn20Warning warning:

  The legacy calling style of select() is deprecated and will be removed
  in SQLAlchemy 2.0.  Please use the new calling style described at
  select().

Change-Id: I3a944dedc43502183726797279e1db3b1d5cb98d
Signed-off-by: Stephen Finucane <stephenfin@redhat.com>

cinder/db/sqlalchemy/api.py

@@ -3361,7 +3361,7 @@ def volume_qos_allows_retype(new_vol_type):
     specifies anything other than the back-end in any of the 2 volume_types.
     """
     # Query to get the qos of the volume type new_vol_type
-    q = sql.select([models.VolumeType.qos_specs_id]).where(
+    q = sql.select(models.VolumeType.qos_specs_id).where(
         and_(~models.VolumeType.deleted, models.VolumeType.id == new_vol_type)
     )
     # Construct the filter to check qos when volume is 'in-use'
@@ -7216,7 +7216,7 @@ def cg_creating_from_src(cg_id=None, cgsnapshot_id=None):
     # subquery to trick MySQL into using the same table in the update and the
     # where clause.
     subq = (
-        sql.select([models.ConsistencyGroup])
+        sql.select(models.ConsistencyGroup)
         .where(
             and_(
                 ~models.ConsistencyGroup.deleted,
@@ -7608,7 +7608,7 @@ def group_creating_from_src(group_id=None, group_snapshot_id=None):
     # subquery to trick MySQL into using the same table in the update and the
     # where clause.
     subq = (
-        sql.select([models.Group])
+        sql.select(models.Group)
         .where(and_(~models.Group.deleted, models.Group.status == 'creating'))
         .alias('group2')
     )
@@ -7624,7 +7624,7 @@ def group_creating_from_src(group_id=None, group_snapshot_id=None):
         )
         raise exception.ProgrammingError(reason=msg)
 
-    return sql.exists([subq]).where(match_id)
+    return sql.exists(subq).where(match_id)
 
 
 @require_admin_context

cinder/db/sqlalchemy/models.py

@@ -150,7 +150,7 @@ class Cluster(BASE, CinderBase):
     # Last heartbeat reported by any of the services of this cluster.  This is
     # not deferred since we always want to load this field.
     last_heartbeat = column_property(
-        sa.select([func.max(Service.updated_at)])
+        sa.select(func.max(Service.updated_at))
         .where(sa.and_(Service.cluster_name == name, ~Service.deleted))
         .correlate_except(Service)
         .scalar_subquery(),
@@ -159,7 +159,7 @@ class Cluster(BASE, CinderBase):
 
     # Number of existing services for this cluster
     num_hosts = column_property(
-        sa.select([func.count(Service.id)])
+        sa.select(func.count(Service.id))
         .where(sa.and_(Service.cluster_name == name, ~Service.deleted))
         .correlate_except(Service)
         .scalar_subquery(),
@@ -169,7 +169,7 @@ class Cluster(BASE, CinderBase):
 
     # Number of services that are down for this cluster
     num_down_hosts = column_property(
-        sa.select([func.count(Service.id)])
+        sa.select(func.count(Service.id))
         .where(
             sa.and_(
                 Service.cluster_name == name,

cinder/tests/fixtures.py

@@ -218,13 +218,6 @@ class WarningsFixture(fixtures.Fixture):
             category=sqla_exc.SADeprecationWarning,
         )
 
-        warnings.filterwarnings(
-            'ignore',
-            module='cinder',
-            message=r'The legacy calling style of select\(\) is deprecated ',
-            category=sqla_exc.SADeprecationWarning,
-        )
-
         self.addCleanup(self._reset_warning_filters)
 
     def _reset_warning_filters(self):

doc/source/contributor/api_conditional_updates.rst

@@ -458,9 +458,12 @@ these filters using the select subquery method like this:
 .. code:: python
 
     def cg_creating_from_src(cg_id):
-       subq = sql.select([models.ConsistencyGroup]).where(and_(
-           ~model.deleted,
-           model.status == 'creating')).alias('cg2')
+       subq = sql.select(models.ConsistencyGroup).where(
+           and_(
+               ~model.deleted,
+               model.status == 'creating'
+           )
+       ).alias('cg2')
 
        return sql.exists([subq]).where(subq.c.source_cgid == cgid)