Make instance object tolerate isotime strings

Any time we get a db object over RPC, the datetime has been
serialized to an isotime string. We have other legacy code that
needs to tolerate this, and those hacks would need to be
replicated in the objects transition. Instead, make the instance
object type function tolerate isotime-formatted strings so that
we can more easily convert RPC-transited database objects
until we're fully converted, at which time we could remove the
tolerance. Luckily, the objects still end up with a datetime
internally, which means the rest of the code can stop needing to
handle strings and datetimes gracefully.

Related to blueprint unified-object-model

Change-Id: I132559d3541d19353de6acc36a2740185e564105

3 files changed, 14 insertions, 6 deletions

diff --git a/nova/objects/base.py b/nova/objects/base.py
index abeebf990..0cfd08e6b 100644
--- a/nova/objects/base.py
+++ b/nova/objects/base.py
@@ -168,9 +168,9 @@ class NovaObject(object):
     # by subclasses, but that is a special case. Objects inheriting from
     # other objects will not receive this merging of fields contents.
     fields = {
-        'created_at': obj_utils.datetime_or_none,
-        'updated_at': obj_utils.datetime_or_none,
-        'deleted_at': obj_utils.datetime_or_none,
+        'created_at': obj_utils.datetime_or_str_or_none,
+        'updated_at': obj_utils.datetime_or_str_or_none,
+        'deleted_at': obj_utils.datetime_or_str_or_none,
         }
 
     def __init__(self):
diff --git a/nova/objects/instance.py b/nova/objects/instance.py
index 836d78c08..dbf9786df 100644
--- a/nova/objects/instance.py
+++ b/nova/objects/instance.py
@@ -58,9 +58,9 @@ class Instance(base.NovaObject):
 
         'reservation_id': obj_utils.str_or_none,
 
-        'scheduled_at': obj_utils.datetime_or_none,
-        'launched_at': obj_utils.datetime_or_none,
-        'terminated_at': obj_utils.datetime_or_none,
+        'scheduled_at': obj_utils.datetime_or_str_or_none,
+        'launched_at': obj_utils.datetime_or_str_or_none,
+        'terminated_at': obj_utils.datetime_or_str_or_none,
 
         'availability_zone': obj_utils.str_or_none,
 
diff --git a/nova/objects/utils.py b/nova/objects/utils.py
index 042b7b36e..dd654045c 100644
--- a/nova/objects/utils.py
+++ b/nova/objects/utils.py
@@ -27,6 +27,14 @@ def datetime_or_none(dt):
     raise ValueError('A datetime.datetime is required here')
 
 
+# NOTE(danms): Being tolerant of isotime strings here will help us
+# during our objects transition
+def datetime_or_str_or_none(val):
+    if isinstance(val, basestring):
+        return timeutils.parse_isotime(val)
+    return datetime_or_none(val)
+
+
 def int_or_none(val):
     """Attempt to parse an integer value, or None."""
     if val is None: