Update created_at column of ft_billing to be non-nullable

`created_at` was added previously and made nullable temporarily. This
commit now populates the column, ensures that it will always have a
value, and makes `created_at` non-nullable.

app/commands.py

@@ -412,10 +412,10 @@ def migrate_data_to_ft_billing(start_date, end_date):
         sql = \
             """
             insert into ft_billing (bst_date, template_id, service_id, notification_type, provider, rate_multiplier,
-                international, billable_units, notifications_sent, rate)
+                international, billable_units, notifications_sent, rate, created_at)
                 select bst_date, template_id, service_id, notification_type, provider, rate_multiplier, international,
                     sum(billable_units) as billable_units, sum(notifications_sent) as notification_sent,
-                    case when notification_type = 'sms' then sms_rate else letter_rate end as rate
+                    case when notification_type = 'sms' then sms_rate else letter_rate end as rate, created_at
                 from (
                     select
                         n.id,
@@ -441,7 +441,8 @@ def migrate_data_to_ft_billing(start_date, end_date):
                         and s.crown = l.crown and n.notification_type='letter'), 0) as letter_rate,
                         coalesce(n.international, false) as international,
                         n.billable_units,
-                        1 as notifications_sent
+                        1 as notifications_sent,
+                        now() as created_at
                     from public.notification_history n
                     left join services s on s.id = n.service_id
                     where n.key_type!='test'
@@ -452,12 +453,13 @@ def migrate_data_to_ft_billing(start_date, end_date):
                         and n.created_at < (date :end + time '00:00:00') at time zone 'Europe/London' at time zone 'UTC'
                     ) as individual_record
                 group by bst_date, template_id, service_id, notification_type, provider, rate_multiplier, international,
-                    sms_rate, letter_rate
+                    sms_rate, letter_rate, created_at
                 order by bst_date
             on conflict on constraint ft_billing_pkey do update set
              billable_units = excluded.billable_units,
              notifications_sent = excluded.notifications_sent,
-             rate = excluded.rate
+             rate = excluded.rate,
+             updated_at = now()
             """
 
         result = db.session.execute(sql, {"start": process_date, "end": process_date + timedelta(days=1)})

app/dao/fact_billing_dao.py

@@ -229,7 +229,8 @@ def update_fact_billing(data, process_day):
     stmt = stmt.on_conflict_do_update(
         constraint="ft_billing_pkey",
         set_={"notifications_sent": stmt.excluded.notifications_sent,
-              "billable_units": stmt.excluded.billable_units
+              "billable_units": stmt.excluded.billable_units,
+              "updated_at": datetime.utcnow()
               }
     )
     db.session.connection().execute(stmt)

app/models.py

@@ -1774,7 +1774,7 @@ class FactBilling(db.Model):
     rate = db.Column(db.Numeric(), nullable=True)
     billable_units = db.Column(db.Integer(), nullable=True)
     notifications_sent = db.Column(db.Integer(), nullable=True)
-    created_at = db.Column(db.DateTime, nullable=True, default=datetime.datetime.utcnow)
+    created_at = db.Column(db.DateTime, nullable=False, default=datetime.datetime.utcnow)
     updated_at = db.Column(db.DateTime, nullable=True, onupdate=datetime.datetime.utcnow)
 
 

migrations/versions/0194_ft_billing_created_at.py

@@ -0,0 +1,23 @@
+"""
+
+Revision ID: 0194_ft_billing_created_at
+Revises: 0193_add_ft_billing_timestamps
+Create Date: 2018-05-22 14:34:27.852096
+
+"""
+from alembic import op
+import sqlalchemy as sa
+from sqlalchemy.dialects import postgresql
+
+revision = '0194_ft_billing_created_at'
+down_revision = '0193_add_ft_billing_timestamps'
+
+
+def upgrade():
+    op.execute("UPDATE ft_billing SET created_at = NOW()")
+    op.alter_column('ft_billing', 'created_at', nullable=False)
+
+
+def downgrade():
+    op.alter_column('ft_billing', 'created_at', nullable=True)
+    op.execute("UPDATE ft_billing SET created_at = null")

tests/app/celery/test_reporting_tasks.py

@@ -447,6 +447,7 @@ def test_create_nightly_billing_update_when_record_exists(
     assert len(records) == 1
     assert records[0].bst_date == date(2018, 1, 14)
     assert records[0].billable_units == 1
+    assert not records[0].updated_at
 
     sample_notification(
         notify_db,
@@ -465,3 +466,4 @@ def test_create_nightly_billing_update_when_record_exists(
     create_nightly_billing()
     assert len(records) == 1
     assert records[0].billable_units == 2
+    assert records[0].updated_at