Remove instances of the "diaper pattern"

Anywhere "except:" occurs, I tried to replace it with an explicit except on
known error types. If none were known, Except was used.

In the process I've been able to unearth a few evasive bugs and clean up some
adjacent code.

1 files changed, 8 insertions, 6 deletions

diff --git a/nova/db/sqlalchemy/api.py b/nova/db/sqlalchemy/api.py
index 4f1445217..ce12ba4e0 100644
--- a/nova/db/sqlalchemy/api.py
+++ b/nova/db/sqlalchemy/api.py
@@ -3178,8 +3178,9 @@ def instance_metadata_delete_all(context, instance_id):
 
 @require_context
 @require_instance_exists
-def instance_metadata_get_item(context, instance_id, key):
-    session = get_session()
+def instance_metadata_get_item(context, instance_id, key, session=None):
+    if not session:
+        session = get_session()
 
     meta_result = session.query(models.InstanceMetadata).\
                     filter_by(instance_id=instance_id).\
@@ -3205,7 +3206,7 @@ def instance_metadata_update_or_create(context, instance_id, metadata):
         try:
             meta_ref = instance_metadata_get_item(context, instance_id, key,
                                                         session)
-        except:
+        except exception.InstanceMetadataNotFound, e:
             meta_ref = models.InstanceMetadata()
         meta_ref.update({"key": key, "value": value,
                             "instance_id": instance_id,
@@ -3300,8 +3301,9 @@ def instance_type_extra_specs_delete(context, instance_type_id, key):
 
 
 @require_context
-def instance_type_extra_specs_get_item(context, instance_type_id, key):
-    session = get_session()
+def instance_type_extra_specs_get_item(context, instance_type_id, key, session=None):
+    if not session:
+        session = get_session()
 
     spec_result = session.query(models.InstanceTypeExtraSpecs).\
                     filter_by(instance_type_id=instance_type_id).\
@@ -3327,7 +3329,7 @@ def instance_type_extra_specs_update_or_create(context, instance_type_id,
                                                           instance_type_id,
                                                           key,
                                                           session)
-        except:
+        except exception.InstanceTypeExtraSpecsNotFound, e:
             spec_ref = models.InstanceTypeExtraSpecs()
         spec_ref.update({"key": key, "value": value,
                          "instance_type_id": instance_type_id,