Deal with cinder-backup service absent

cinder-backup service is optional, and currently not discoverable with
non-admin scoped tokens.

This patch introduces a new config option `volumes.backups_enabled`
(defaults to True for backward compat).
When set to False, it will fail validation of stacks containing volume
resources with deletion_policy set to Snapshot,
as such stacks will be undeletable in the absence of cinder-backup
service.

Change-Id: I10c4787870e7b240d775aa5d66eb1d0a6d837d8d
Partial-Bug: #1595159

devstack/lib/heat

@@ -195,6 +195,10 @@ function configure_heat {
     iniset $HEAT_CONF cache enabled "True"
     iniset $HEAT_CONF cache backend "dogpile.cache.memory"
 
+    if ! is_service_enabled c-bak; then
+        iniset $HEAT_CONF volumes backups_enabled false
+    fi
+
     sudo install -d -o $STACK_USER $HEAT_ENV_DIR $HEAT_TEMPLATES_DIR
 
     # copy the default environment

heat/common/config.py

@@ -344,6 +344,14 @@ revision_opts = [
                       'separately, you can move this section to a different '
                       'file and add it as another config option.'))]
 
+volumes_group = cfg.OptGroup('volumes')
+volumes_opts = [
+    cfg.BoolOpt('backups_enabled',
+                default=True,
+                help=_("Indicate if cinder-backup service is enabled. "
+                       "This is a temporary workaround until cinder-backup "
+                       "service becomes discoverable, see LP#1334856."))]
+
 
 def startup_sanity_check():
     if (not cfg.CONF.stack_user_domain_id and
@@ -377,6 +385,7 @@ def list_opts():
     yield paste_deploy_group.name, paste_deploy_opts
     yield auth_password_group.name, auth_password_opts
     yield revision_group.name, revision_opts
+    yield volumes_group.name, volumes_opts
     yield profiler.list_opts()[0]
     yield 'clients', default_clients_opts
 

heat/engine/resources/volume_base.py

@@ -11,10 +11,13 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+from oslo_config import cfg
+
 from heat.common import exception
 from heat.common.i18n import _
 from heat.engine.clients import progress
 from heat.engine import resource
+from heat.engine import rsrc_defn
 
 
 class BaseVolume(resource.Resource):
@@ -159,6 +162,17 @@ class BaseVolume(resource.Resource):
                 return False
         return True
 
+    @classmethod
+    def validate_deletion_policy(cls, policy):
+        res = super(BaseVolume, cls).validate_deletion_policy(policy)
+        if res:
+            return res
+        if (policy == rsrc_defn.ResourceDefinition.SNAPSHOT and
+                not cfg.CONF.volumes.backups_enabled):
+            msg = _('"%s" deletion policy not supported - '
+                    'volume backup service is not enabled.') % policy
+            raise exception.StackValidationFailed(message=msg)
+
 
 class BaseVolumeAttachment(resource.Resource):
     """Base Volume Attachment Manager."""

heat/tests/aws/test_volume.py

@@ -736,3 +736,14 @@ class VolumeTest(vt_base.BaseVolumeTest):
                       six.text_type(ex))
         self.assertEqual((rsrc.UPDATE, rsrc.FAILED), rsrc.state)
         self.m.VerifyAll()
+
+    def test_vaildate_deletion_policy(self):
+        cfg.CONF.set_override('backups_enabled', False, group='volumes')
+        stack_name = 'test_volume_validate_deletion_policy'
+        self.t['Resources']['DataVolume']['DeletionPolicy'] = 'Snapshot'
+        stack = utils.parse_stack(self.t, stack_name=stack_name)
+        rsrc = self.get_volume(self.t, stack, 'DataVolume')
+        self.assertRaisesRegex(
+            exception.StackValidationFailed,
+            'volume backup service is not enabled',
+            rsrc.validate)

heat/tests/openstack/cinder/test_volume.py

@@ -16,6 +16,7 @@ import copy
 import json
 
 from cinderclient import exceptions as cinder_exp
+from oslo_config import cfg
 import six
 
 from heat.common import exception
@@ -1247,3 +1248,14 @@ class CinderVolumeTest(vt_base.BaseVolumeTest):
             stack.t.resource_definitions(stack)['volume'],
             stack)
         self.assertIsNone(rsrc.handle_delete_snapshot(mock_vs))
+
+    def test_vaildate_deletion_policy(self):
+        cfg.CONF.set_override('backups_enabled', False, group='volumes')
+        stack_name = 'test_volume_validate_deletion_policy'
+        self.t['resources']['volume']['deletion_policy'] = 'Snapshot'
+        stack = utils.parse_stack(self.t, stack_name=stack_name)
+        rsrc = self.get_volume(self.t, stack, 'volume')
+        self.assertRaisesRegex(
+            exception.StackValidationFailed,
+            'volume backup service is not enabled',
+            rsrc.validate)

heat/tests/openstack/cinder/test_volume_utils.py

@@ -64,16 +64,20 @@ class BaseVolumeTest(common.HeatTestCase):
         self.cinder_fc.volumes.get(fva.id).AndReturn(fv_ready)
         return fv_ready
 
-    def create_volume(self, t, stack, resource_name):
+    def get_volume(self, t, stack, resource_name):
         if self.use_cinder:
             Volume = os_vol.CinderVolume
         else:
             data = t['Resources'][resource_name]
             data['Properties']['AvailabilityZone'] = 'nova'
             Volume = aws_vol.Volume
-        rsrc = Volume(resource_name,
+        vol = Volume(resource_name,
                      stack.t.resource_definitions(stack)[resource_name],
                      stack)
+        return vol
+
+    def create_volume(self, t, stack, resource_name):
+        rsrc = self.get_volume(t, stack, resource_name)
         self.assertIsNone(rsrc.validate())
         scheduler.TaskRunner(rsrc.create)()
         self.assertEqual((rsrc.CREATE, rsrc.COMPLETE), rsrc.state)