Fix upgrade logic to allow for bundled changes

The upgrade path logic was built to force a developer pattern to break
things such as new tables and features across multiple patches, and
the status check *can* explicitly fail if we don't explicitly go
hint to it that we've added table. Yes, we have a hard coded list...

Anyway, a better pattern is allow the db sync process to do the
appropriate needful. Run the status check, if it fails, fallback
and update the schema.

Also handles the explicit failure error and tries to return a human
friendly error message for when the table is not present.

In the end this allows us to merge schema changes such as additional
tables with their underlying objects and properly handle things as
long as the schema update works as expected. This allows us to
leverage an operational model of performing upgrades.

Change-Id: Id5f2a8068bc064e1ed1e376524850e4739f79ef2

1 files changed, 10 insertions, 1 deletions

diff --git a/ironic/cmd/status.py b/ironic/cmd/status.py
index 37fdbaf7d..10c8a5bfd 100644
--- a/ironic/cmd/status.py
+++ b/ironic/cmd/status.py
@@ -19,6 +19,7 @@ from oslo_db.sqlalchemy import enginefacade
 from oslo_db.sqlalchemy import utils
 from oslo_upgradecheck import common_checks
 from oslo_upgradecheck import upgradecheck
+from sqlalchemy import exc as sa_exc
 
 from ironic.cmd import dbsync
 from ironic.common.i18n import _
@@ -44,7 +45,15 @@ class Checks(upgradecheck.UpgradeCommands):
         .version field in the database, with the expected versions
         of these objects.
         """
-        msg = dbsync.DBCommand().check_obj_versions(ignore_missing_tables=True)
+        try:
+            # NOTE(TheJulia): Seems an exception is raised by sqlalchemy
+            # when a table is missing, so lets catch it, since it is fatal.
+            msg = dbsync.DBCommand().check_obj_versions(
+                ignore_missing_tables=True)
+        except sa_exc.NoSuchTableError as e:
+            msg = ('Database table missing. Please ensure you have '
+                   'updated the database schema. Not Found: %s' % e)
+            return upgradecheck.Result(upgradecheck.Code.FAILURE, details=msg)
 
         if not msg:
             return upgradecheck.Result(upgradecheck.Code.SUCCESS)