Make nova-manage online migrations more verbose

This makes the online_data_migrations command for nova-manage a little
more verbose in what it is doing. Each time it is run, it will show you
all the migrations that need running and how many records remain for
each. Basically, you run this until you see all zeroes.

Change-Id: I78c6312ec8e226a6ef9185382b6180f246f8fe84

nova/cmd/manage.py

@@ -66,6 +66,7 @@ from oslo_log import log as logging
 import oslo_messaging as messaging
 from oslo_utils import importutils
 from oslo_utils import uuidutils
+import prettytable
 import six
 import six.moves.urllib.parse as urlparse
 
@@ -881,6 +882,7 @@ class DbCommands(object):
 
     def _run_migration(self, ctxt, max_count):
         ran = 0
+        migrations = {}
         for migration_meth in self.online_migrations:
             count = max_count - ran
             try:
@@ -890,16 +892,20 @@ class DbCommands(object):
                       method=migration_meth))
                 found = done = 0
 
+            name = migration_meth.__name__
             if found:
                 print(_('%(total)i rows matched query %(meth)s, %(done)i '
                         'migrated') % {'total': found,
-                                       'meth': migration_meth.__name__,
+                                       'meth': name,
                                        'done': done})
+            migrations.setdefault(name, (0, 0))
+            migrations[name] = (migrations[name][0] + found,
+                                migrations[name][1] + done)
             if max_count is not None:
                 ran += done
                 if ran >= max_count:
                     break
-        return ran
+        return migrations
 
     @args('--max-count', metavar='<number>', dest='max_count',
           help='Maximum number of objects to consider')
@@ -920,11 +926,22 @@ class DbCommands(object):
             print(_('Running batches of %i until complete') % max_count)
 
         ran = None
+        migration_info = {}
         while ran is None or ran != 0:
-            ran = self._run_migration(ctxt, max_count)
+            migrations = self._run_migration(ctxt, max_count)
+            migration_info.update(migrations)
+            ran = sum([done for found, done in migrations.values()])
             if not unlimited:
                 break
 
+        t = prettytable.PrettyTable([_('Migration'),
+                                     _('Total Needed'),
+                                     _('Completed')])
+        for name in sorted(migration_info.keys()):
+            info = migration_info[name]
+            t.add_row([name, info[0], info[1]])
+        print(t)
+
         return ran and 1 or 0
 
 

nova/tests/unit/test_nova_manage.py

@@ -592,12 +592,24 @@ class DBCommandsTestCase(test.NoDBTestCase):
 
     @mock.patch('nova.context.get_admin_context')
     def test_online_migrations(self, mock_get_context):
+        self.useFixture(fixtures.MonkeyPatch('sys.stdout', StringIO()))
         ctxt = mock_get_context.return_value
         command_cls = self._fake_db_command()
         command = command_cls()
         command.online_data_migrations(10)
         command_cls.online_migrations[0].assert_called_once_with(ctxt, 10)
         command_cls.online_migrations[1].assert_called_once_with(ctxt, 6)
+        expected = """\
+5 rows matched query mock_mig_1, 4 migrated
+6 rows matched query mock_mig_2, 6 migrated
++------------+--------------+-----------+
+| Migration  | Total Needed | Completed |
++------------+--------------+-----------+
+| mock_mig_1 |      5       |     4     |
+| mock_mig_2 |      6       |     6     |
++------------+--------------+-----------+
+"""
+        self.assertEqual(expected, sys.stdout.getvalue())
 
     @mock.patch('nova.context.get_admin_context')
     def test_online_migrations_no_max_count(self, mock_get_context):
@@ -622,6 +634,7 @@ class DBCommandsTestCase(test.NoDBTestCase):
     def test_online_migrations_error(self):
         fake_migration = mock.MagicMock()
         fake_migration.side_effect = Exception
+        fake_migration.__name__ = 'fake'
         command_cls = self._fake_db_command((fake_migration,))
         command = command_cls()
         command.online_data_migrations(None)
@@ -636,19 +649,19 @@ class DBCommandsTestCase(test.NoDBTestCase):
 
     def test_online_migrations_no_max(self):
         with mock.patch.object(self.commands, '_run_migration') as rm:
-            rm.return_value = 0
+            rm.return_value = {}
             self.assertEqual(0,
                              self.commands.online_data_migrations())
 
     def test_online_migrations_finished(self):
         with mock.patch.object(self.commands, '_run_migration') as rm:
-            rm.return_value = 0
+            rm.return_value = {}
             self.assertEqual(0,
                              self.commands.online_data_migrations(max_count=5))
 
     def test_online_migrations_not_finished(self):
         with mock.patch.object(self.commands, '_run_migration') as rm:
-            rm.return_value = 5
+            rm.return_value = {'mig': (10, 5)}
             self.assertEqual(1,
                              self.commands.online_data_migrations(max_count=5))
 

releasenotes/notes/verbose-online-migrations-bd6f57e43328d554.yaml

@@ -0,0 +1,6 @@
+---
+features:
+  - The nova-manage online_data_migrations command now prints a
+    tabular summary of completed and remaining records. The goal
+    here is to get all your numbers to zero. The previous execution
+    return code behavior is retained for scripting.