Auto add timestamp fields into db model

Created new class ModelBaseWithTimeStamp() to automatically handle
these timestamp fields: created_at and updated_at when user
create/update key-value pair in database.

Change-Id: I8fe69e2ec9866d0ccf020f3687af754d96242f46
Closes-Bug: #1652390

test-requirements.txt

@@ -5,6 +5,7 @@
 hacking<0.11,>=0.10.0
 
 coverage>=3.6
+freezegun>=0.3.6  # Apache-2.0
 python-subunit>=0.0.18
 sphinx!=1.2.0,!=1.3b1,<1.3,>=1.1.2
 oslosphinx>=2.5.0 # Apache-2.0

valence/db/models.py

@@ -11,6 +11,7 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+import datetime
 import json
 import os
 
@@ -80,7 +81,47 @@ class ModelBase(base.ObjectBase):
         client.delete(path)
 
 
-class PodManager(ModelBase):
+class ModelBaseWithTimeStamp(ModelBase):
+
+    def __init__(self, *args, **kwargs):
+        """Inject 'created_at' and 'updated_at' fields"""
+        timestamp_fields = {
+            'created_at': {
+                'validate': types.Text.validate
+            },
+            'updated_at': {
+                'validate': types.Text.validate
+            }
+        }
+        self.fields.update(timestamp_fields)
+
+        super(ModelBaseWithTimeStamp, self).__init__(*args, **kwargs)
+
+    def save(self, *args, **kwargs):
+        """Update all timestamp fields when save new object
+
+        Set current utc time to 'created_at' and 'updated_at' fields when
+        save this key-value pair at the first time.
+        """
+        utcnow = datetime.datetime.utcnow().strftime("%Y-%m-%d %H:%M:%S UTC")
+        self.created_at = utcnow
+        self.updated_at = utcnow
+
+        super(ModelBaseWithTimeStamp, self).save(*args, **kwargs)
+
+    def update(self, *args, **kwargs):
+        """Update 'updated_at' timestamp when udpate object
+
+        Set current utc time to 'updated_at' field when update this
+        key-value pair.
+        """
+        utcnow = datetime.datetime.utcnow().strftime("%Y-%m-%d %H:%M:%S UTC")
+        self.updated_at = utcnow
+
+        super(ModelBaseWithTimeStamp, self).update(*args, **kwargs)
+
+
+class PodManager(ModelBaseWithTimeStamp):
 
     path = "/pod_managers"
 
@@ -111,11 +152,5 @@ class PodManager(ModelBase):
         },
         'bookmark_link': {
             'validate': types.Text.validate
-        },
-        'created_at': {
-            'validate': types.Text.validate
-        },
-        'updated_at': {
-            'validate': types.Text.validate
         }
     }

valence/tests/unit/db/test_db_api.py

@@ -16,6 +16,7 @@ import mock
 import unittest
 
 import etcd
+import freezegun
 
 from valence.db import api as db_api
 from valence.tests.unit.db import utils
@@ -23,10 +24,14 @@ from valence.tests.unit.db import utils
 
 class TestDBAPI(unittest.TestCase):
 
+    @freezegun.freeze_time("2017-01-01")
     @mock.patch('etcd.Client.write')
     @mock.patch('etcd.Client.read')
     def test_create_podmanager(self, mock_etcd_read, mock_etcd_write):
         podmanager = utils.get_test_podmanager()
+        fake_utcnow = '2017-01-01 00:00:00 UTC'
+        podmanager['created_at'] = fake_utcnow
+        podmanager['updated_at'] = fake_utcnow
 
         # Mark this uuid don't exist in etcd db
         mock_etcd_read.side_effect = etcd.EtcdKeyNotFound
@@ -76,6 +81,7 @@ class TestDBAPI(unittest.TestCase):
         mock_etcd_delete.assert_called_with(
             '/pod_managers/' + podmanager['uuid'])
 
+    @freezegun.freeze_time("2017-01-01")
     @mock.patch('etcd.Client.write')
     @mock.patch('etcd.Client.read')
     def test_update_podmanager(self, mock_etcd_read, mock_etcd_write):
@@ -84,7 +90,10 @@ class TestDBAPI(unittest.TestCase):
         mock_etcd_read.return_value = utils.get_etcd_read_result(
             podmanager['uuid'], json.dumps(podmanager))
 
+        fake_utcnow = '2017-01-01 00:00:00 UTC'
+        podmanager['updated_at'] = fake_utcnow
         podmanager.update({'url': 'new_url'})
+
         result = db_api.Connection.update_podmanager(
             podmanager['uuid'], {'url': 'new_url'})
 

valence/tests/unit/db/utils.py

@@ -53,6 +53,6 @@ def get_test_podmanager(**kwargs):
         'location': kwargs.get('location', 'fake_location'),
         'redfish_link': kwargs.get('redfish_link', 'fake_redfish_link'),
         'bookmark_link': kwargs.get('bookmark_link', 'fake_bookmark_link'),
-        'created_at': kwargs.get('created_at', '2017-01-01 00:0:00'),
+        'created_at': kwargs.get('created_at', '2016-01-01 00:00:00 UTC'),
-        'updated_at': kwargs.get('updated_at', '2017-01-01 00:0:00'),
+        'updated_at': kwargs.get('updated_at', '2016-01-01 00:00:00 UTC'),
     }