[placement] add error.code on a ConcurrentUpdateDetected

A pending api-sig guideline
I473918ce9c6b49c0b904e93b7140421525f4e7c0 reflects discussion amongst
various parties that adding error codes to structured error responses
should not be considered a breaking API change.

Given that, it is simply "okay" to add them. This change adds
errors.CONCURRENT_UPDATE wherever the ConcurrentUpdateDetected results
in an HTTPConflict (409) response.

In practice this means that if microversion 1.23 or beyond is being
used, there will be a code in any error response, and for some
409 responses that code will be `placement.concurrent_update`.

Note that because we haven't instrumented a way to cause a truly
concurrent update, we've never had real tests for this kind of
thing.

Change-Id: I5a164a0ee298846231113ad7b62b82a3e8f1f409

nova/api/openstack/placement/handlers/aggregate.py

@@ -17,6 +17,7 @@ from oslo_utils import encodeutils
 from oslo_utils import timeutils
 import webob
 
+from nova.api.openstack.placement import errors
 from nova.api.openstack.placement import exception
 from nova.api.openstack.placement import microversion
 from nova.api.openstack.placement.objects import resource_provider as rp_obj
@@ -69,8 +70,11 @@ def _set_aggregates(resource_provider, aggregate_uuids,
     try:
         resource_provider.set_aggregates(
             aggregate_uuids, increment_generation=increment_generation)
-    except (exception.ConcurrentUpdateDetected,
-            db_exc.DBDuplicateEntry) as exc:
+    except exception.ConcurrentUpdateDetected as exc:
+        raise webob.exc.HTTPConflict(
+            _('Update conflict: %(error)s') % {'error': exc},
+            comment=errors.CONCURRENT_UPDATE)
+    except db_exc.DBDuplicateEntry as exc:
         raise webob.exc.HTTPConflict(
             _('Update conflict: %(error)s') % {'error': exc})
 

nova/api/openstack/placement/handlers/inventory.py

@@ -202,7 +202,8 @@ def create_inventory(req):
     except (exception.ConcurrentUpdateDetected,
             db_exc.DBDuplicateEntry) as exc:
         raise webob.exc.HTTPConflict(
-            _('Update conflict: %(error)s') % {'error': exc})
+            _('Update conflict: %(error)s') % {'error': exc},
+            comment=errors.CONCURRENT_UPDATE)
     except (exception.InvalidInventoryCapacity,
             exception.NotFound) as exc:
         raise webob.exc.HTTPBadRequest(
@@ -239,7 +240,8 @@ def delete_inventory(req):
             exception.InventoryInUse) as exc:
         raise webob.exc.HTTPConflict(
             _('Unable to delete inventory of class %(class)s: %(error)s') %
-            {'class': resource_class, 'error': exc})
+            {'class': resource_class, 'error': exc},
+            comment=errors.CONCURRENT_UPDATE)
     except exception.NotFound as exc:
         raise webob.exc.HTTPNotFound(
             _('No inventory of class %(class)s found for delete: %(error)s') %
@@ -356,7 +358,8 @@ def set_inventories(req):
     except (exception.ConcurrentUpdateDetected,
             db_exc.DBDuplicateEntry) as exc:
         raise webob.exc.HTTPConflict(
-            _('update conflict: %(error)s') % {'error': exc})
+            _('update conflict: %(error)s') % {'error': exc},
+            comment=errors.CONCURRENT_UPDATE)
     except exception.InventoryInUse as exc:
         raise webob.exc.HTTPConflict(
             _('update conflict: %(error)s') % {'error': exc},
@@ -395,7 +398,8 @@ def delete_inventories(req):
             _('Unable to delete inventory for resource provider '
               '%(rp_uuid)s because the inventory was updated by '
               'another process. Please retry your request.')
-              % {'rp_uuid': resource_provider.uuid})
+              % {'rp_uuid': resource_provider.uuid},
+              comment=errors.CONCURRENT_UPDATE)
     except exception.InventoryInUse as ex:
         # NOTE(mriedem): This message cannot change without impacting the
         # nova.scheduler.client.report._RE_INV_IN_USE regex.
@@ -445,7 +449,8 @@ def update_inventory(req):
     except (exception.ConcurrentUpdateDetected,
             db_exc.DBDuplicateEntry) as exc:
         raise webob.exc.HTTPConflict(
-            _('update conflict: %(error)s') % {'error': exc})
+            _('update conflict: %(error)s') % {'error': exc},
+            comment=errors.CONCURRENT_UPDATE)
     except exception.InventoryWithResourceClassNotFound as exc:
         raise webob.exc.HTTPBadRequest(
             _('No inventory record with resource class for resource provider '

nova/api/openstack/placement/handlers/trait.py

@@ -17,6 +17,7 @@ from oslo_utils import encodeutils
 from oslo_utils import timeutils
 import webob
 
+from nova.api.openstack.placement import errors
 from nova.api.openstack.placement import exception
 from nova.api.openstack.placement import microversion
 from nova.api.openstack.placement.objects import resource_provider as rp_obj
@@ -260,7 +261,8 @@ def delete_traits_for_resource_provider(req):
     try:
         resource_provider.set_traits(rp_obj.TraitList(objects=[]))
     except exception.ConcurrentUpdateDetected as e:
-        raise webob.exc.HTTPConflict(e.format_message())
+        raise webob.exc.HTTPConflict(e.format_message(),
+                                     comment=errors.CONCURRENT_UPDATE)
 
     req.response.status = 204
     req.response.content_type = None