Handle isotime deprecation in oslo_utils.timeutils

oslo_utils.timeutils is deprecating isotime(). In reality they are
deprecating some other things as well but Trove doesn't (currently)
use any of those things.

Much has been written on the subject of this deprecation. I think the
proposal to merely replace isotime with datetime.datetime.isoformat()
is a little simplistic. Well intentioned, but nonetheless I believe
that it is simplistic.

The primary issue I could find with oslo_utils.timeutils.isotime() was
the fact that it was naive. I think it could well have been fixed in
oslo_utils but for whatever reason(s) oslo decided not to want to go
that route.

The primary challenge from Trove's perspective is that I want to
respect the existing API contract while at the same time get an
implementation of time handling that is not identical in its flaws
with oslo_utils.timeutils.isotime().

This change set attempts to address that by making
trove.common.timeutils.isotime() that is aware. It also implements a
utcnow_aware() function that is aware.

ISO 8601 allows for four representations of timezone and those are

<time>Z
<time>[+-]hh:mm
<time>[+-]hhmm
<time>[+-]hh

Trove conventionally used the first one, even if the time wasn't
really a UTC time. That's one of the things being fixed here.

In review cp16net asked whether this change removes the 'Z' at the end
of time strings generated by the isotime() function. The answer is
NO. The new isotime() function performs identical to the old and now
deprecated function in oslo_utils.timeutils for UTC (Z) times.

There was a utcnow() function in trove.common.utils which just wrapped
datetime.datetime.utcnow(). That has been moved now to
trove.common.timeutils with the other new time related functions.

There were a couple of places in Trove where code was using
datetime.now() which was not ideal. Those have been corrected now as
well.

Unit tests have been proposed for the new routines.

Closes-Bug: #1532120
Change-Id: Ic5abf6669edd4f1a9fd62e61f437565aa887aebe

26 files changed, 287 insertions, 90 deletions

diff --git a/trove/common/notification.py b/trove/common/notification.py
index 73ec7990..49a3aad5 100644
--- a/trove/common/notification.py
+++ b/trove/common/notification.py
@@ -18,11 +18,11 @@ import copy
 import traceback
 
 from oslo_log import log as logging
-from oslo_utils import timeutils
 
 from trove.common import cfg
 from trove.common.exception import TroveError
 from trove.common.i18n import _
+from trove.common import timeutils
 from trove.conductor import api as conductor_api
 from trove import rpc
 
diff --git a/trove/common/timeutils.py b/trove/common/timeutils.py
new file mode 100644
index 00000000..44a0b9ff
--- /dev/null
+++ b/trove/common/timeutils.py
@@ -0,0 +1,84 @@
+# Copyright 2016 Tesora Inc.
+# All Rights Reserved.
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+from datetime import datetime
+from datetime import timedelta
+from datetime import tzinfo
+
+
+class zulutime(tzinfo):
+    """A tzinfo class for zulu time"""
+
+    def utcoffset(self, dt):
+        return timedelta(0)
+
+    def tzname(self, dt):
+        return "Z"
+
+    def dst(self, dt):
+        return timedelta(0)
+
+
+def utcnow_aware():
+    """An aware utcnow() that uses zulutime for the tzinfo."""
+    return datetime.now(zulutime())
+
+
+def utcnow():
+    """A wrapper around datetime.datetime.utcnow(). We're doing this
+       because it is mock'ed in some places.
+    """
+    return datetime.utcnow()
+
+
+def isotime(tm=None, subsecond=False):
+    """Stringify a time and return it in an ISO 8601 format. Subsecond
+       information is only provided if the subsecond parameter is set
+       to True (default: False).
+
+       If a time (tm) is provided, it will be stringified. If tm is
+       not provided, the current UTC time is used instead.
+
+       The timezone for UTC time will be provided as 'Z' and not
+       [+-]00:00. Time zone differential for non UTC times will be
+       provided as the full six character string format provided by
+       datetime.datetime.isoformat() namely [+-]NN:NN.
+
+       If an invalid time is provided such that tm.utcoffset() causes
+       a ValueError, that exception will be propagated.
+    """
+
+    _dt = tm if tm else utcnow_aware()
+
+    if not subsecond:
+        _dt = _dt.replace(microsecond=0)
+
+    # might cause an exception if _dt has a bad utcoffset.
+    delta = _dt.utcoffset() if _dt.utcoffset() else timedelta(0)
+
+    ts = None
+
+    if delta == timedelta(0):
+        # either we are provided a naive time (tm) or no tm, or an
+        # aware UTC time. In any event, we want to use 'Z' for the
+        # timezone rather than the full 6 character offset.
+        _dt = _dt.replace(tzinfo=None)
+        ts = _dt.isoformat()
+        ts += 'Z'
+    else:
+        # an aware non-UTC time was provided
+        ts = _dt.isoformat()
+
+    return ts
diff --git a/trove/common/utils.py b/trove/common/utils.py
index 9a81be45..774cfc66 100644
--- a/trove/common/utils.py
+++ b/trove/common/utils.py
@@ -15,7 +15,6 @@
 """I totally stole most of this from melange, thx guys!!!"""
 
 import collections
-import datetime
 import inspect
 import os
 import shutil
@@ -29,7 +28,6 @@ from oslo_log import log as logging
 from oslo_service import loopingcall
 from oslo_utils import importutils
 from oslo_utils import strutils
-from oslo_utils import timeutils
 from passlib import pwd
 import six
 import six.moves.urllib.parse as urlparse
@@ -46,7 +44,6 @@ import_object = importutils.import_object
 import_module = importutils.import_module
 bool_from_string = strutils.bool_from_string
 execute = processutils.execute
-isotime = timeutils.isotime
 
 
 def build_jinja_environment():
@@ -99,10 +96,6 @@ def generate_uuid():
     return str(uuid.uuid4())
 
 
-def utcnow():
-    return datetime.datetime.utcnow()
-
-
 def raise_if_process_errored(process, exception):
     try:
         err = process.stderr.read()
diff --git a/trove/configuration/models.py b/trove/configuration/models.py
index 3ca3c2bd..599a1501 100644
--- a/trove/configuration/models.py
+++ b/trove/configuration/models.py
@@ -13,7 +13,6 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
-from datetime import datetime
 import json
 
 from oslo_log import log as logging
@@ -22,6 +21,7 @@ from trove.common import cfg
 from trove.common import exception
 from trove.common.exception import ModelNotFoundError
 from trove.common.i18n import _
+from trove.common import timeutils
 from trove.common import utils
 from trove.datastore import models as dstore_models
 from trove.db import get_db_api
@@ -103,7 +103,7 @@ class Configuration(object):
 
     @staticmethod
     def delete(context, group):
-        deleted_at = datetime.utcnow()
+        deleted_at = timeutils.utcnow()
         Configuration.remove_all_items(context, group.id, deleted_at)
         group.deleted = True
         group.deleted_at = deleted_at
@@ -313,7 +313,7 @@ class DatastoreConfigurationParameters(object):
         config_param = DatastoreConfigurationParameters.load_parameter_by_name(
             version_id, config_param_name)
         config_param.deleted = True
-        config_param.deleted_at = datetime.utcnow()
+        config_param.deleted_at = timeutils.utcnow()
         config_param.save()
 
     @classmethod
diff --git a/trove/configuration/service.py b/trove/configuration/service.py
index 5cf9ff8b..463cae93 100644
--- a/trove/configuration/service.py
+++ b/trove/configuration/service.py
@@ -13,8 +13,6 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
-from datetime import datetime
-
 from oslo_log import log as logging
 import six
 
@@ -27,6 +25,7 @@ from trove.common import notification
 from trove.common.notification import StartNotification, EndNotification
 from trove.common import pagination
 from trove.common import policy
+from trove.common import timeutils
 from trove.common import wsgi
 from trove.configuration import models
 from trove.configuration.models import DBConfigurationParameter
@@ -194,7 +193,7 @@ class ConfigurationsController(wsgi.Controller):
                                name=group.name, description=group.description):
             items = self._configuration_items_list(group,
                                                    body['configuration'])
-            deleted_at = datetime.utcnow()
+            deleted_at = timeutils.utcnow()
             models.Configuration.remove_all_items(context, group.id,
                                                   deleted_at)
             models.Configuration.save(group, items)
diff --git a/trove/datastore/models.py b/trove/datastore/models.py
index 981489ed..e7a7a200 100644
--- a/trove/datastore/models.py
+++ b/trove/datastore/models.py
@@ -21,6 +21,7 @@ from trove.common import cfg
 from trove.common import exception
 from trove.common.i18n import _
 from trove.common.remote import create_nova_client
+from trove.common import timeutils
 from trove.common import utils
 from trove.db import get_db_api
 from trove.db import models as dbmodels
@@ -631,7 +632,7 @@ class DatastoreVersionMetadata(object):
                 key=key, value=value)
             if db_record.deleted == 1:
                 db_record.deleted = 0
-                db_record.updated_at = utils.utcnow()
+                db_record.updated_at = timeutils.utcnow()
                 db_record.save()
                 return
             else:
diff --git a/trove/db/models.py b/trove/db/models.py
index 0553bcfd..8d8c7ad5 100644
--- a/trove/db/models.py
+++ b/trove/db/models.py
@@ -19,6 +19,7 @@ from trove.common import exception
 from trove.common.i18n import _
 from trove.common import models
 from trove.common import pagination
+from trove.common import timeutils
 from trove.common import utils
 from trove.db import db_query
 from trove.db import get_db_api
@@ -33,7 +34,7 @@ class DatabaseModelBase(models.ModelBase):
     def create(cls, **values):
         init_vals = {
             'id': utils.generate_uuid(),
-            'created': utils.utcnow(),
+            'created': timeutils.utcnow(),
         }
         if hasattr(cls, 'deleted'):
             init_vals['deleted'] = False
@@ -58,20 +59,20 @@ class DatabaseModelBase(models.ModelBase):
     def save(self):
         if not self.is_valid():
             raise exception.InvalidModelError(errors=self.errors)
-        self['updated'] = utils.utcnow()
+        self['updated'] = timeutils.utcnow()
         LOG.debug("Saving %(name)s: %(dict)s",
                   {'name': self.__class__.__name__,
                    'dict': strutils.mask_dict_password(self.__dict__)})
         return self.db_api.save(self)
 
     def delete(self):
-        self['updated'] = utils.utcnow()
+        self['updated'] = timeutils.utcnow()
         LOG.debug("Deleting %(name)s: %(dict)s",
                   {'name': self.__class__.__name__,
                    'dict': strutils.mask_dict_password(self.__dict__)})
 
         if self.preserve_on_delete:
-            self['deleted_at'] = utils.utcnow()
+            self['deleted_at'] = timeutils.utcnow()
             self['deleted'] = True
             return self.db_api.save(self)
         else:
@@ -81,7 +82,7 @@ class DatabaseModelBase(models.ModelBase):
         for key in values:
             if hasattr(self, key):
                 setattr(self, key, values[key])
-        self['updated'] = utils.utcnow()
+        self['updated'] = timeutils.utcnow()
         return self.db_api.save(self)
 
     def __init__(self, **kwargs):
diff --git a/trove/extensions/common/models.py b/trove/extensions/common/models.py
index 4102a425..c67438d0 100644
--- a/trove/extensions/common/models.py
+++ b/trove/extensions/common/models.py
@@ -18,7 +18,7 @@ from oslo_log import log as logging
 from trove.common.db import models as guest_models
 from trove.common import exception
 from trove.common.remote import create_guest_client
-from trove.common import utils
+from trove.common import timeutils
 from trove.db import get_db_api
 from trove.instance import models as base_models
 
@@ -106,7 +106,7 @@ class RootHistory(object):
     def __init__(self, instance_id, user):
         self.id = instance_id
         self.user = user
-        self.created = utils.utcnow()
+        self.created = timeutils.utcnow()
 
     def save(self):
         LOG.debug("Saving %(name)s: %(dict)s",
diff --git a/trove/extensions/mgmt/instances/models.py b/trove/extensions/mgmt/instances/models.py
index b2b6fb0d..64da1a1e 100644
--- a/trove/extensions/mgmt/instances/models.py
+++ b/trove/extensions/mgmt/instances/models.py
@@ -19,7 +19,7 @@ from trove.common import cfg
 from trove.common import exception
 from trove.common.i18n import _
 from trove.common import remote
-from trove.common import utils
+from trove.common import timeutils
 from trove.extensions.mysql import models as mysql_models
 from trove.instance import models as instance_models
 from trove import rpc
@@ -186,12 +186,11 @@ class NotificationTransformer(object):
 
     @staticmethod
     def _get_audit_period():
-        now = datetime.datetime.now()
-        audit_start = utils.isotime(
-            now - datetime.timedelta(
-                seconds=CONF.exists_notification_interval),
-            subsecond=True)
-        audit_end = utils.isotime(now, subsecond=True)
+        now = timeutils.utcnow()
+        start_time = now - datetime.timedelta(
+            seconds=CONF.exists_notification_interval)
+        audit_start = timeutils.isotime(start_time)
+        audit_end = timeutils.isotime(now)
         return audit_start, audit_end
 
     def _get_service_id(self, datastore_manager, id_map):
diff --git a/trove/guestagent/backup/backupagent.py b/trove/guestagent/backup/backupagent.py
index 71ccaa52..9d13e746 100644
--- a/trove/guestagent/backup/backupagent.py
+++ b/trove/guestagent/backup/backupagent.py
@@ -15,13 +15,13 @@
 #
 
 from oslo_log import log as logging
+from oslo_utils import timeutils
 
 from trove.backup.state import BackupState
 from trove.common import cfg
 from trove.common.i18n import _
 from trove.common.strategies.storage import get_storage_strategy
 from trove.conductor import api as conductor_api
-from trove.guestagent.common import timeutils
 from trove.guestagent.dbaas import get_filesystem_volume_stats
 from trove.guestagent.strategies.backup.base import BackupError
 from trove.guestagent.strategies.backup.base import UnknownBackupType
@@ -74,7 +74,7 @@ class BackupAgent(object):
             'state': BackupState.BUILDING,
         }
         conductor.update_backup(CONF.guest_id,
-                                sent=timeutils.float_utcnow(),
+                                sent=timeutils.utcnow_ts(microsecond=True),
                                 **backup_state)
         LOG.debug("Updated state for %s to %s.", backup_id, backup_state)
 
@@ -120,7 +120,8 @@ class BackupAgent(object):
         finally:
             LOG.info(_("Completed backup %(backup_id)s."), backup_state)
             conductor.update_backup(CONF.guest_id,
-                                    sent=timeutils.float_utcnow(),
+                                    sent=timeutils.utcnow_ts(
+                                        microsecond=True),
                                     **backup_state)
             LOG.debug("Updated state for %s to %s.",
                       backup_id, backup_state)
diff --git a/trove/guestagent/common/timeutils.py b/trove/guestagent/common/timeutils.py
deleted file mode 100644
index e5895bd8..00000000
--- a/trove/guestagent/common/timeutils.py
+++ /dev/null
@@ -1,19 +0,0 @@
-#  Licensed under the Apache License, Version 2.0 (the "License"); you may
-#  not use this file except in compliance with the License. You may obtain
-#  a copy of the License at
-#
-#       http://www.apache.org/licenses/LICENSE-2.0
-#
-#  Unless required by applicable law or agreed to in writing, software
-#  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
-#  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
-#  License for the specific language governing permissions and limitations
-#  under the License.
-
-from datetime import datetime
-
-from oslo_utils import timeutils
-
-
-def float_utcnow():
-    return float(datetime.strftime(timeutils.utcnow(), "%s.%f"))
diff --git a/trove/guestagent/datastore/service.py b/trove/guestagent/datastore/service.py
index d03d87f8..bedd63c3 100644
--- a/trove/guestagent/datastore/service.py
+++ b/trove/guestagent/datastore/service.py
@@ -18,6 +18,7 @@ import os
 import time
 
 from oslo_log import log as logging
+from oslo_utils import timeutils
 
 from trove.common import cfg
 from trove.common import context as trove_context
@@ -26,7 +27,7 @@ from trove.common import instance
 from trove.conductor import api as conductor_api
 from trove.guestagent.common import guestagent_utils
 from trove.guestagent.common import operating_system
-from trove.guestagent.common import timeutils
+
 
 LOG = logging.getLogger(__name__)
 CONF = cfg.CONF
@@ -167,7 +168,8 @@ class BaseDbStatus(object):
 
             heartbeat = {'service_status': status.description}
             conductor_api.API(context).heartbeat(
-                CONF.guest_id, heartbeat, sent=timeutils.float_utcnow())
+                CONF.guest_id, heartbeat,
+                sent=timeutils.utcnow_ts(microsecond=True))
             LOG.debug("Successfully cast set_status.")
             self.status = status
         else:
diff --git a/trove/guestagent/guest_log.py b/trove/guestagent/guest_log.py
index 8e93e4a1..bc1cc000 100644
--- a/trove/guestagent/guest_log.py
+++ b/trove/guestagent/guest_log.py
@@ -12,7 +12,6 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
-from datetime import datetime
 import enum
 import hashlib
 import os
@@ -26,6 +25,7 @@ from trove.common import exception
 from trove.common.i18n import _
 from trove.common.remote import create_swift_client
 from trove.common import stream_codecs
+from trove.common import timeutils
 from trove.guestagent.common import operating_system
 from trove.guestagent.common.operating_system import FileMode
 
@@ -404,7 +404,7 @@ class GuestLog(object):
             'log': self._name}
 
     def _object_name(self):
-        return 'log-%s' % str(datetime.utcnow()).replace(' ', 'T')
+        return 'log-%s' % str(timeutils.utcnow()).replace(' ', 'T')
 
     def _get_meta_details(self):
         LOG.debug("Getting meta details for '%s'", self._name)
diff --git a/trove/guestagent/models.py b/trove/guestagent/models.py
index 4cdc4279..cdf64651 100644
--- a/trove/guestagent/models.py
+++ b/trove/guestagent/models.py
@@ -20,6 +20,7 @@ from oslo_log import log as logging
 from trove.common import cfg
 from trove.common import exception
 from trove.common.i18n import _
+from trove.common import timeutils
 from trove.common import utils
 from trove.db import get_db_api
 from trove.db import models as dbmodels
@@ -56,7 +57,7 @@ class AgentHeartBeat(dbmodels.DatabaseModelBase):
     def save(self):
         if not self.is_valid():
             raise exception.InvalidModelError(errors=self.errors)
-        self['updated_at'] = utils.utcnow()
+        self['updated_at'] = timeutils.utcnow()
         LOG.debug("Saving %(name)s: %(dict)s",
                   {'name': self.__class__.__name__, 'dict': self.__dict__})
         return get_db_api().save(self)
diff --git a/trove/instance/models.py b/trove/instance/models.py
index d1825ef5..922d3b06 100644
--- a/trove/instance/models.py
+++ b/trove/instance/models.py
@@ -39,6 +39,7 @@ from trove.common.remote import create_guest_client
 from trove.common.remote import create_nova_client
 from trove.common import server_group as srv_grp
 from trove.common import template
+from trove.common import timeutils
 from trove.common.trove_remote import create_trove_client
 from trove.common import utils
 from trove.configuration.models import Configuration
@@ -651,7 +652,7 @@ class BaseInstance(SimpleInstance):
         pass
 
     def delete_async(self):
-        deleted_at = datetime.utcnow()
+        deleted_at = timeutils.utcnow()
         self._delete_resources(deleted_at)
         LOG.debug("Setting instance %s to be deleted.", self.id)
         self.update_db(deleted=True, deleted_at=deleted_at,
@@ -1217,7 +1218,7 @@ class Instance(BuiltInstance):
             raise exception.BadRequest(_("Instance %s is not a replica"
                                        " source.") % self.id)
         service = InstanceServiceStatus.find_by(instance_id=self.id)
-        last_heartbeat_delta = datetime.utcnow() - service.updated_at
+        last_heartbeat_delta = timeutils.utcnow() - service.updated_at
         agent_expiry_interval = timedelta(seconds=CONF.agent_heartbeat_expiry)
         if last_heartbeat_delta < agent_expiry_interval:
             raise exception.BadRequest(_("Replica Source %s cannot be ejected"
@@ -1788,7 +1789,7 @@ class InstanceServiceStatus(dbmodels.DatabaseModelBase):
         self.status_description = value.description
 
     def save(self):
-        self['updated_at'] = utils.utcnow()
+        self['updated_at'] = timeutils.utcnow()
         return get_db_api().save(self)
 
     status = property(get_status, set_status)
diff --git a/trove/limits/views.py b/trove/limits/views.py
index 6c483c08..f381d1ca 100644
--- a/trove/limits/views.py
+++ b/trove/limits/views.py
@@ -14,7 +14,8 @@
 #    under the License.
 
 import datetime
-from oslo_utils import timeutils
+
+from trove.common import timeutils
 
 
 class LimitView(object):
@@ -27,7 +28,7 @@ class LimitView(object):
         next_avail = get_utc(self.rate_limit.get("resetTime", 0))
 
         return {"limit": {
-            "nextAvailable": timeutils.isotime(at=next_avail),
+            "nextAvailable": timeutils.isotime(next_avail),
             "remaining": self.rate_limit.get("remaining", 0),
             "unit": self.rate_limit.get("unit", ""),
             "value": self.rate_limit.get("value", ""),
diff --git a/trove/module/models.py b/trove/module/models.py
index dc9138bb..80df8cb7 100644
--- a/trove/module/models.py
+++ b/trove/module/models.py
@@ -16,7 +16,6 @@
 
 """Model classes that form the core of Module functionality."""
 
-from datetime import datetime
 import hashlib
 import six
 from sqlalchemy.sql.expression import or_
@@ -27,6 +26,7 @@ from trove.common import cfg
 from trove.common import crypto_utils
 from trove.common import exception
 from trove.common.i18n import _
+from trove.common import timeutils
 from trove.common import utils
 from trove.datastore import models as datastore_models
 from trove.db import models
@@ -266,7 +266,7 @@ class Module(object):
             module.priority_apply, None)
         Module.enforce_live_update(module.id, module.live_update, module.md5)
         module.deleted = True
-        module.deleted_at = datetime.utcnow()
+        module.deleted_at = timeutils.utcnow()
         module.save()
 
     @staticmethod
@@ -342,7 +342,7 @@ class Module(object):
         if module.datastore_version_id:
             module.datastore_version_id = ds_ver_id
 
-        module.updated = datetime.utcnow()
+        module.updated = timeutils.utcnow()
         DBModule.save(module)
 
     @staticmethod
@@ -424,7 +424,7 @@ class InstanceModule(object):
     @staticmethod
     def delete(context, instance_module):
         instance_module.deleted = True
-        instance_module.deleted_at = datetime.utcnow()
+        instance_module.deleted_at = timeutils.utcnow()
         instance_module.save()
 
     @staticmethod
@@ -440,7 +440,7 @@ class InstanceModule(object):
 
     @staticmethod
     def update(context, instance_module):
-        instance_module.updated = datetime.utcnow()
+        instance_module.updated = timeutils.utcnow()
         DBInstanceModule.save(instance_module)
 
 
diff --git a/trove/quota/models.py b/trove/quota/models.py
index 64e225c0..31b7542d 100644
--- a/trove/quota/models.py
+++ b/trove/quota/models.py
@@ -14,6 +14,7 @@
 
 
 from trove.common import cfg
+from trove.common import timeutils
 from trove.common import utils
 from trove.db import models as dbmodels
 
@@ -31,8 +32,8 @@ class Quota(dbmodels.DatabaseModelBase):
                     'hard_limit', 'id']
 
     def __init__(self, tenant_id, resource, hard_limit,
-                 id=utils.generate_uuid(), created=utils.utcnow(),
-                 update=utils.utcnow()):
+                 id=utils.generate_uuid(), created=timeutils.utcnow(),
+                 update=timeutils.utcnow()):
         self.tenant_id = tenant_id
         self.resource = resource
         self.hard_limit = hard_limit
diff --git a/trove/taskmanager/models.py b/trove/taskmanager/models.py
index e104df11..6e9272a3 100755
--- a/trove/taskmanager/models.py
+++ b/trove/taskmanager/models.py
@@ -21,7 +21,6 @@ from eventlet import greenthread
 from eventlet.timeout import Timeout
 from novaclient import exceptions as nova_exceptions
 from oslo_log import log as logging
-from oslo_utils import timeutils
 from swiftclient.client import ClientException
 
 from trove.backup import models as bkup_models
@@ -61,6 +60,7 @@ from trove.common.remote import create_guest_client
 from trove.common import server_group as srv_grp
 from trove.common.strategies.cluster import strategy
 from trove.common import template
+from trove.common import timeutils
 from trove.common import utils
 from trove.common.utils import try_recover
 from trove.extensions.mysql import models as mysql_models
@@ -315,7 +315,7 @@ class ClusterTasks(Cluster):
         LOG.debug("setting cluster %s as deleted.", cluster_id)
         cluster = DBCluster.find_by(id=cluster_id)
         cluster.deleted = True
-        cluster.deleted_at = utils.utcnow()
+        cluster.deleted_at = timeutils.utcnow()
         cluster.task_status = tasks.ClusterTasks.NONE
         cluster.save()
         LOG.debug("end delete_cluster for id: %s", cluster_id)
diff --git a/trove/tests/examples/snippets.py b/trove/tests/examples/snippets.py
index 8e539ebf..65d90198 100644
--- a/trove/tests/examples/snippets.py
+++ b/trove/tests/examples/snippets.py
@@ -71,8 +71,9 @@ def set_fake_stuff(uuid=None, minute=None, unique_id=None):
 def monkey_patch_uuid_and_date():
     import uuid
     uuid.uuid4 = get_uuid
+    from trove.common import timeutils
     from trove.common import utils
-    utils.utcnow = get_now
+    timeutils.utcnow = get_now
     utils.generate_uuid = get_uuid
 
 
diff --git a/trove/tests/scenario/runners/test_runners.py b/trove/tests/scenario/runners/test_runners.py
index a1f2fa1b..d858893d 100644
--- a/trove/tests/scenario/runners/test_runners.py
+++ b/trove/tests/scenario/runners/test_runners.py
@@ -31,6 +31,7 @@ from troveclient.compat import exceptions
 from trove.common import cfg
 from trove.common import exception
 from trove.common.strategies.strategy import Strategy
+from trove.common import timeutils
 from trove.common import utils
 from trove.common.utils import poll_until, build_polling_task
 from trove.tests.config import CONFIG
@@ -323,7 +324,7 @@ class TestRunner(object):
         self.def_timeout = timeout
 
         self.instance_info.name = "TEST_" + datetime.datetime.strftime(
-            datetime.datetime.now(), '%Y_%m_%d__%H_%M_%S')
+            timeutils.utcnow(), '%Y_%m_%d__%H_%M_%S')
         self.instance_info.dbaas_datastore = CONFIG.dbaas_datastore
         self.instance_info.dbaas_datastore_version = (
             CONFIG.dbaas_datastore_version)
diff --git a/trove/tests/unittests/backup/test_backup_models.py b/trove/tests/unittests/backup/test_backup_models.py
index 315a508e..a4964ae6 100644
--- a/trove/tests/unittests/backup/test_backup_models.py
+++ b/trove/tests/unittests/backup/test_backup_models.py
@@ -23,6 +23,7 @@ from trove.backup import state
 from trove.common import context
 from trove.common import exception
 from trove.common import remote
+from trove.common import timeutils
 from trove.common import utils
 from trove.db.models import DatabaseModelBase
 from trove.instance import models as instance_models
@@ -54,7 +55,7 @@ class BackupCreateTest(trove_testtools.TestCase):
     def setUp(self):
         super(BackupCreateTest, self).setUp()
         util.init_db()
-        self.context, self.instance_id = _prep_conf(utils.utcnow())
+        self.context, self.instance_id = _prep_conf(timeutils.utcnow())
         self.created = False
 
     def tearDown(self):
@@ -241,7 +242,7 @@ class BackupDeleteTest(trove_testtools.TestCase):
     def setUp(self):
         super(BackupDeleteTest, self).setUp()
         util.init_db()
-        self.context, self.instance_id = _prep_conf(utils.utcnow())
+        self.context, self.instance_id = _prep_conf(timeutils.utcnow())
 
     def tearDown(self):
         super(BackupDeleteTest, self).tearDown()
@@ -272,7 +273,7 @@ class BackupORMTest(trove_testtools.TestCase):
     def setUp(self):
         super(BackupORMTest, self).setUp()
         util.init_db()
-        self.context, self.instance_id = _prep_conf(utils.utcnow())
+        self.context, self.instance_id = _prep_conf(timeutils.utcnow())
         self.backup = models.DBBackup.create(tenant_id=self.context.tenant,
                                              name=BACKUP_NAME,
                                              state=BACKUP_STATE,
@@ -449,7 +450,7 @@ class PaginationTests(trove_testtools.TestCase):
     def setUp(self):
         super(PaginationTests, self).setUp()
         util.init_db()
-        self.context, self.instance_id = _prep_conf(utils.utcnow())
+        self.context, self.instance_id = _prep_conf(timeutils.utcnow())
         # Create a bunch of backups
         bkup_info = {
             'tenant_id': self.context.tenant,
@@ -507,7 +508,7 @@ class OrderingTests(trove_testtools.TestCase):
     def setUp(self):
         super(OrderingTests, self).setUp()
         util.init_db()
-        now = utils.utcnow()
+        now = timeutils.utcnow()
         self.context, self.instance_id = _prep_conf(now)
         info = {
             'tenant_id': self.context.tenant,
diff --git a/trove/tests/unittests/common/test_timeutils.py b/trove/tests/unittests/common/test_timeutils.py
new file mode 100644
index 00000000..6027b7c1
--- /dev/null
+++ b/trove/tests/unittests/common/test_timeutils.py
@@ -0,0 +1,129 @@
+# Copyright 2016 Tesora Inc.
+# All Rights Reserved.
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+from datetime import datetime
+from datetime import timedelta
+from datetime import tzinfo
+
+from trove.common import timeutils
+from trove.tests.unittests import trove_testtools
+
+
+class bogus_tzinfo(tzinfo):
+    """A bogus tzinfo class"""
+    def utcoffset(self, dt):
+        return timedelta(hours=2)
+
+    def tzname(self, dt):
+        return "BOGUS"
+
+    def dst(self, dt):
+        return timedelta(hours=1)
+
+
+class invalid_tzinfo(tzinfo):
+    """A bogus tzinfo class"""
+    def utcoffset(self, dt):
+        return timedelta(hours=25)
+
+    def tzname(self, dt):
+        return "INVALID"
+
+    def dst(self, dt):
+        return timedelta(hours=25)
+
+
+class TestTroveTimeutils(trove_testtools.TestCase):
+
+    def setUp(self):
+        super(TestTroveTimeutils, self).setUp()
+
+    def tearDown(self):
+        super(TestTroveTimeutils, self).tearDown()
+
+    def test_utcnow_tz(self):
+        dt = timeutils.utcnow()
+
+        self.assertIsNone(dt.tzinfo)
+
+    def test_utcnow_aware_tz(self):
+        dt = timeutils.utcnow_aware()
+
+        self.assertEqual(timedelta(0), dt.utcoffset())
+        self.assertEqual('Z', dt.tzname())
+
+    def test_isotime(self):
+        dt = timeutils.utcnow_aware()
+
+        expected = "%04d-%02d-%02dT%02d:%02d:%02dZ" % (
+            dt.year, dt.month, dt.day, dt.hour, dt.minute, dt.second)
+
+        self.assertEqual(expected, timeutils.isotime(dt))
+
+    def test_isotime_subsecond(self):
+        dt = timeutils.utcnow_aware()
+
+        expected = "%04d-%02d-%02dT%02d:%02d:%02d.%06dZ" % (
+            dt.year, dt.month, dt.day,
+            dt.hour, dt.minute, dt.second,
+            dt.microsecond)
+
+        self.assertEqual(expected, timeutils.isotime(dt, subsecond=True))
+
+    def test_isotime_unaware(self):
+        dt = timeutils.utcnow()
+
+        expected = "%04d-%02d-%02dT%02d:%02d:%02d.%06dZ" % (
+            dt.year, dt.month, dt.day,
+            dt.hour, dt.minute, dt.second,
+            dt.microsecond)
+
+        self.assertEqual(expected, timeutils.isotime(dt, subsecond=True))
+
+    def test_isotime_unaware_subsecond(self):
+        dt = timeutils.utcnow()
+
+        expected = "%04d-%02d-%02dT%02d:%02d:%02d.%06dZ" % (
+            dt.year, dt.month, dt.day,
+            dt.hour, dt.minute, dt.second,
+            dt.microsecond)
+
+        self.assertEqual(expected, timeutils.isotime(dt, subsecond=True))
+
+    def test_bogus_unaware(self):
+        dt = datetime.now(bogus_tzinfo())
+
+        expected = "%04d-%02d-%02dT%02d:%02d:%02d.%06d+02:00" % (
+            dt.year, dt.month, dt.day,
+            dt.hour, dt.minute, dt.second,
+            dt.microsecond)
+
+        self.assertEqual(expected, timeutils.isotime(dt, subsecond=True))
+
+    def test_bogus_unaware_subsecond(self):
+        dt = datetime.now(bogus_tzinfo())
+
+        expected = "%04d-%02d-%02dT%02d:%02d:%02d.%06d+02:00" % (
+            dt.year, dt.month, dt.day,
+            dt.hour, dt.minute, dt.second,
+            dt.microsecond)
+
+        self.assertEqual(expected, timeutils.isotime(dt, subsecond=True))
+
+    def test_throws_exception(self):
+        dt = datetime.now()
+        dt = dt.replace(tzinfo=invalid_tzinfo())
+
+        self.assertRaises(ValueError, timeutils.isotime, dt)
diff --git a/trove/tests/unittests/conductor/test_methods.py b/trove/tests/unittests/conductor/test_methods.py
index 86e6a832..56278adc 100644
--- a/trove/tests/unittests/conductor/test_methods.py
+++ b/trove/tests/unittests/conductor/test_methods.py
@@ -13,6 +13,7 @@
 #    under the License.
 
 from mock import patch
+from oslo_utils import timeutils
 
 from trove.backup import models as bkup_models
 from trove.backup import state
@@ -20,7 +21,6 @@ from trove.common import exception as t_exception
 from trove.common.instance import ServiceStatuses
 from trove.common import utils
 from trove.conductor import manager as conductor_manager
-from trove.guestagent.common import timeutils
 from trove.instance import models as t_models
 from trove.tests.unittests import trove_testtools
 from trove.tests.unittests.util import util
@@ -151,7 +151,7 @@ class ConductorMethodTests(trove_testtools.TestCase):
         build_p = {'service_status': ServiceStatuses.BUILDING.description}
         iss_id = self._create_iss()
         iss = self._get_iss(iss_id)
-        now = timeutils.float_utcnow()
+        now = timeutils.utcnow_ts(microsecond=True)
         future = now + 60
         self.cond_mgr.heartbeat(None, self.instance_id, new_p, sent=now)
         self.cond_mgr.heartbeat(None, self.instance_id, build_p, sent=future)
@@ -164,7 +164,7 @@ class ConductorMethodTests(trove_testtools.TestCase):
         build_p = {'service_status': ServiceStatuses.BUILDING.description}
         iss_id = self._create_iss()
         iss = self._get_iss(iss_id)
-        now = timeutils.float_utcnow()
+        now = timeutils.utcnow_ts(microsecond=True)
         past = now - 60
         self.cond_mgr.heartbeat(None, self.instance_id, new_p, sent=past)
         self.cond_mgr.heartbeat(None, self.instance_id, build_p, sent=past)
@@ -176,7 +176,7 @@ class ConductorMethodTests(trove_testtools.TestCase):
         new_name = "renamed"
         bkup_id = self._create_backup(old_name)
         bkup = self._get_backup(bkup_id)
-        now = timeutils.float_utcnow()
+        now = timeutils.utcnow_ts(microsecond=True)
         future = now + 60
         self.cond_mgr.update_backup(None, self.instance_id, bkup_id,
                                     sent=now, name=old_name)
@@ -190,7 +190,7 @@ class ConductorMethodTests(trove_testtools.TestCase):
         new_name = "renamed"
         bkup_id = self._create_backup(old_name)
         bkup = self._get_backup(bkup_id)
-        now = timeutils.float_utcnow()
+        now = timeutils.utcnow_ts(microsecond=True)
         past = now - 60
         self.cond_mgr.update_backup(None, self.instance_id, bkup_id,
                                     sent=now, name=old_name)
diff --git a/trove/tests/unittests/guestagent/test_models.py b/trove/tests/unittests/guestagent/test_models.py
index 783f8e20..6e45834b 100644
--- a/trove/tests/unittests/guestagent/test_models.py
+++ b/trove/tests/unittests/guestagent/test_models.py
@@ -16,6 +16,7 @@ from datetime import datetime
 
 from mock import Mock, MagicMock, patch
 
+from trove.common import timeutils
 from trove.common import utils
 from trove.db import models as dbmodels
 from trove.db.sqlalchemy import api as dbapi
@@ -27,7 +28,7 @@ class AgentHeartBeatTest(trove_testtools.TestCase):
     def setUp(self):
         super(AgentHeartBeatTest, self).setUp()
         self.origin_get_db_api = dbmodels.get_db_api
-        self.origin_utcnow = utils.utcnow
+        self.origin_utcnow = timeutils.utcnow
         self.origin_db_api_save = dbapi.save
         self.origin_is_valid = dbmodels.DatabaseModelBase.is_valid
         self.origin_generate_uuid = utils.generate_uuid
@@ -35,7 +36,7 @@ class AgentHeartBeatTest(trove_testtools.TestCase):
     def tearDown(self):
         super(AgentHeartBeatTest, self).tearDown()
         dbmodels.get_db_api = self.origin_get_db_api
-        utils.utcnow = self.origin_utcnow
+        timeutils.utcnow = self.origin_utcnow
         dbapi.save = self.origin_db_api_save
         dbmodels.DatabaseModelBase.is_valid = self.origin_is_valid
         utils.generate_uuid = self.origin_generate_uuid
@@ -52,14 +53,14 @@ class AgentHeartBeatTest(trove_testtools.TestCase):
 
     @patch('trove.db.models.DatabaseModelBase')
     def test_save(self, dmb_mock):
-        utils.utcnow = Mock()
+        timeutils.utcnow = Mock()
         dbmodels.get_db_api = MagicMock(
             return_value=dbmodels.DatabaseModelBase)
         dbapi.save = Mock()
         dbmodels.DatabaseModelBase.is_valid = Mock(return_value=True)
         self.heartBeat = models.AgentHeartBeat()
         self.heartBeat.save()
-        self.assertEqual(1, utils.utcnow.call_count)
+        self.assertEqual(1, timeutils.utcnow.call_count)
 
     def test_is_active(self):
         models.AGENT_HEARTBEAT = 10000000000
diff --git a/trove/tests/unittests/taskmanager/test_models.py b/trove/tests/unittests/taskmanager/test_models.py
index 7fbba5dd..53bed50d 100644
--- a/trove/tests/unittests/taskmanager/test_models.py
+++ b/trove/tests/unittests/taskmanager/test_models.py
@@ -11,7 +11,6 @@
 #    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 #    License for the specific language governing permissions and limitations
 #    under the License.
-import datetime
 import os
 from tempfile import NamedTemporaryFile
 import uuid
@@ -23,7 +22,6 @@ from mock import Mock, MagicMock, patch, PropertyMock, call
 from novaclient import exceptions as nova_exceptions
 import novaclient.v2.flavors
 import novaclient.v2.servers
-from oslo_utils import timeutils
 from swiftclient.client import ClientException
 from testtools.matchers import Equals, Is
 
@@ -39,6 +37,7 @@ from trove.common.instance import ServiceStatuses
 from trove.common.notification import TroveInstanceModifyVolume
 from trove.common import remote
 import trove.common.template as template
+from trove.common import timeutils
 from trove.common import utils
 from trove.datastore import models as datastore_models
 import trove.db.models
@@ -651,8 +650,8 @@ class BuiltInstanceTasksTest(trove_testtools.TestCase):
                                  datastore_id='id-1',
                                  flavor_id='6',
                                  manager='mysql',
-                                 created=datetime.datetime.utcnow(),
-                                 updated=datetime.datetime.utcnow(),
+                                 created=timeutils.utcnow(),
+                                 updated=timeutils.utcnow(),
                                  compute_instance_id='computeinst-id-1',
                                  tenant_id='testresize-tenant-id',
                                  volume_size='1',