Add started_at attribute to container

In Virtual-kubelet, we need to implement a kubelet
driver for Zun, just the same with ACI. Since Pod
will use the sandbox container start time as the
Pod start time, for align with Pod, we need to record
container started_at time field to record this.

Ref: https://github.com/virtual-kubelet/virtual-kubelet/blob/master/providers/azure/aci.go#L744

Part of blueprint golang-client

Change-Id: Iefedcd828b1b2935892bbe46729cdac8963c1d9a
Signed-off-by: Kevin Zhao <kevin.zhao@arm.com>

zun/db/sqlalchemy/alembic/versions/271c7f45982d_add_started_at_to_container.py

@@ -0,0 +1,34 @@
+#    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.
+
+"""add started_at to containers
+
+Revision ID: 271c7f45982d
+Revises: cff60402dd86
+Create Date: 2018-05-03 11:27:00.722445
+
+"""
+
+# revision identifiers, used by Alembic.
+revision = '271c7f45982d'
+down_revision = 'cff60402dd86'
+branch_labels = None
+depends_on = None
+
+from alembic import op
+import sqlalchemy as sa
+
+
+def upgrade():
+    op.add_column('container',
+                  sa.Column('started_at', sa.DateTime(),
+                            nullable=True))

zun/db/sqlalchemy/models.py

@@ -169,6 +169,7 @@ class Container(Base):
     auto_heal = Column(Boolean, default=False)
     capsule_id = Column(Integer,
                         ForeignKey('capsule.id', ondelete='CASCADE'))
+    started_at = Column(DateTime, default=timeutils.utcnow)
 
 
 class VolumeMapping(Base):

zun/objects/container.py

@@ -59,7 +59,8 @@ class Container(base.ZunPersistentObject, base.ZunObject):
     # Version 1.28: Add 'Dead' to ContainerStatus
     # Version 1.29: Add 'Restarting' to ContainerStatus
     # Version 1.30: Add capsule_id attribute
-    VERSION = '1.30'
+    # Version 1.31: Add 'started_at' attribute
+    VERSION = '1.31'
 
     fields = {
         'id': fields.IntegerField(),
@@ -98,6 +99,7 @@ class Container(base.ZunPersistentObject, base.ZunObject):
         'disk': fields.IntegerField(nullable=True),
         'auto_heal': fields.BooleanField(nullable=True),
         'capsule_id': fields.IntegerField(nullable=True),
+        'started_at': fields.DateTimeField(nullable=True),
     }
 
     @staticmethod

zun/tests/unit/db/utils.py

@@ -101,6 +101,7 @@ def get_test_container(**kwargs):
         'disk': kwargs.get('disk', 20),
         'auto_heal': kwargs.get('auto_heal', False),
         'capsule_id': kwargs.get('capsule_id', 42),
+        'started_at': kwargs.get('started_at'),
     }
 
 

zun/tests/unit/objects/test_objects.py

@@ -344,7 +344,7 @@ class TestObject(test_base.TestCase, _TestObject):
 # For more information on object version testing, read
 # https://docs.openstack.org/zun/latest/
 object_data = {
-    'Container': '1.30-fc17da52173f258245d424c9a5cf99c7',
+    'Container': '1.31-4e1f27e1326bc42c7fa7ca0681bbe883',
     'VolumeMapping': '1.1-50df6202f7846a136a91444c38eba841',
     'Image': '1.1-330e6205c80b99b59717e1cfc6a79935',
     'MyObj': '1.0-34c4b1aadefd177b13f9a2f894cc23cd',