Fix compatibility with oslo.db 12.1.0

oslo.db 12.1.0 has changed the default value for the 'autocommit'
parameter of 'LegacyEngineFacade' from 'True' to 'False'. This is a
necessary step to ensure compatibility with SQLAlchemy 2.0. However, we
are currently relying on the autocommit behavior and need changes to
explicitly manage sessions. Until that happens, we need to override the
default.

This also moves the watcher queue declaration from the pipeline level
(where it is no longer valid) to the project level.

Co-Authored-By: Thierry Carrez <thierry@openstack.org>
Co-Authored-By: Stephen Finucane <stephenfin@redhat.com>
(cherry picked from commit 5d70c207cd)
Change-Id: I7db39d958d087322bfa0aad70dfbd04de9228dd7

.zuul.yaml

@@ -1,4 +1,5 @@
 - project:
+    queue: watcher
     templates:
       - check-requirements
       - openstack-cover-jobs
@@ -14,7 +15,6 @@
         - watcherclient-tempest-functional
         - watcher-tempest-functional-ipv6-only
     gate:
-      queue: watcher
       jobs:
         - watcher-tempest-functional
         - watcher-tempest-functional-ipv6-only

watcher/db/sqlalchemy/api.py

@@ -44,7 +44,11 @@ _FACADE = None
 def _create_facade_lazily():
     global _FACADE
     if _FACADE is None:
-        _FACADE = db_session.EngineFacade.from_config(CONF)
+        # FIXME(amoralej): Remove autocommit=True (and ideally use of
+        # LegacyEngineFacade) asap since it's not compatible with SQLAlchemy
+        # 2.0.
+        _FACADE = db_session.EngineFacade.from_config(CONF,
+                                                      autocommit=True)
     return _FACADE