Add CellMappingList.get_by_disabled() query method

This query methods helps us to query for either the enabled cells if
False is passed as the value to the disabled argument or the disabled
cells if True is passed as a value to the disabled argument in the call.

Related to blueprint cell-disable

Change-Id: I3e0e1da186e4b3531b42e699ebd466280702d588

nova/objects/cell_mapping.py

@@ -12,6 +12,8 @@
 
 from oslo_utils import versionutils
 from sqlalchemy.sql.expression import asc
+from sqlalchemy.sql import false
+from sqlalchemy.sql import true
 
 from nova.db.sqlalchemy import api as db_api
 from nova.db.sqlalchemy import api_models
@@ -130,7 +132,8 @@ def is_cell0(self):
 @base.NovaObjectRegistry.register
 class CellMappingList(base.ObjectListBase, base.NovaObject):
     # Version 1.0: Initial version
-    VERSION = '1.0'
+    # Version 1.1: Add get_by_disabled()
+    VERSION = '1.1'
 
     fields = {
         'objects': fields.ListOfObjectsField('CellMapping'),
@@ -146,3 +149,19 @@ def _get_all_from_db(context):
     def get_all(cls, context):
         db_mappings = cls._get_all_from_db(context)
         return base.obj_make_list(context, cls(), CellMapping, db_mappings)
+
+    @staticmethod
+    @db_api.api_context_manager.reader
+    def _get_by_disabled_from_db(context, disabled):
+        if disabled:
+            return context.session.query(api_models.CellMapping).filter_by(
+                disabled=true()).order_by(asc(api_models.CellMapping.id)).all()
+        else:
+            return context.session.query(api_models.CellMapping).filter_by(
+                disabled=false()).order_by(asc(
+                    api_models.CellMapping.id)).all()
+
+    @base.remotable_classmethod
+    def get_by_disabled(cls, context, disabled):
+        db_mappings = cls._get_by_disabled_from_db(context, disabled)
+        return base.obj_make_list(context, cls(), CellMapping, db_mappings)

nova/tests/functional/db/test_cell_mapping.py

@@ -100,3 +100,21 @@ def test_get_all(self):
             mapping = mappings[db_mapping.uuid]
             for key in cell_mapping.CellMapping.fields.keys():
                 self.assertEqual(db_mapping[key], mapping[key])
+
+    def test_get_by_disabled(self):
+        enabled_mapping = create_mapping(disabled=False)
+        disabled_mapping = create_mapping(disabled=True)
+
+        ctxt = context.RequestContext()
+        mappings = cell_mapping.CellMappingList.get_all(ctxt)
+        self.assertEqual(2, len(mappings))
+        self.assertEqual(enabled_mapping['uuid'], mappings[0].uuid)
+        self.assertEqual(disabled_mapping['uuid'], mappings[1].uuid)
+        mappings = cell_mapping.CellMappingList.get_by_disabled(ctxt,
+                                                                disabled=False)
+        self.assertEqual(1, len(mappings))
+        self.assertEqual(enabled_mapping['uuid'], mappings[0].uuid)
+        mappings = cell_mapping.CellMappingList.get_by_disabled(ctxt,
+                                                                disabled=True)
+        self.assertEqual(1, len(mappings))
+        self.assertEqual(disabled_mapping['uuid'], mappings[0].uuid)

nova/tests/unit/objects/test_cell_mapping.py

@@ -161,6 +161,35 @@ def test_get_all_sorted(self):
         # order
         self.assertEqual([1, 2, 3, 10], ids)
 
+    def test_get_by_disabled(self):
+        for ident in (4, 3):
+            # We start with id's 4 and 3 because we already have 2 enabled cell
+            # mappings in the base test case setup. 4 is before 3 to simply
+            # verify the sorting mechanism.
+            cm = objects.CellMapping(context=self.context,
+                                     id=ident,
+                                     uuid=getattr(uuids, 'cell%i' % ident),
+                                     transport_url='fake://%i' % ident,
+                                     database_connection='fake://%i' % ident,
+                                     disabled=True)
+            cm.create()
+        obj = objects.CellMappingList.get_all(self.context)
+        ids = [c.id for c in obj]
+        # Returns all the cells
+        self.assertEqual([1, 2, 3, 4], ids)
+
+        obj = objects.CellMappingList.get_by_disabled(self.context,
+                                                      disabled=False)
+        ids = [c.id for c in obj]
+        # Returns only the enabled ones
+        self.assertEqual([1, 2], ids)
+
+        obj = objects.CellMappingList.get_by_disabled(self.context,
+                                                      disabled=True)
+        ids = [c.id for c in obj]
+        # Returns only the disabled ones
+        self.assertEqual([3, 4], ids)
+
 
 class TestCellMappingListObject(test_objects._LocalTest,
                                 _TestCellMappingListObject):

nova/tests/unit/objects/test_objects.py

@@ -1065,7 +1065,7 @@ def obj_name(cls):
     'BuildRequest': '1.3-077dee42bed93f8a5b62be77657b7152',
     'BuildRequestList': '1.0-cd95608eccb89fbc702c8b52f38ec738',
     'CellMapping': '1.1-5d652928000a5bc369d79d5bde7e497d',
-    'CellMappingList': '1.0-4ee0d9efdfd681fed822da88376e04d2',
+    'CellMappingList': '1.1-496ef79bb2ab41041fff8bcb57996352',
     'ComputeNode': '1.18-431fafd8ac4a5f3559bd9b1f1332cc22',
     'ComputeNodeList': '1.17-52f3b0962b1c86b98590144463ebb192',
     'CpuDiagnostics': '1.0-d256f2e442d1b837735fd17dfe8e3d47',