[bug 1139713] Fix received_ts migration

fjord/heartbeat/migrations/0007_auto_20150305_1119.py

@@ -38,7 +38,6 @@ def set_received_ts(apps, schema_editor):
 
         ans.received_ts = dt
         ans.save()
-        break
 
 
 class Migration(migrations.Migration):

fjord/heartbeat/migrations/0008_auto_20150305_1442.py

@@ -0,0 +1,56 @@
+# -*- coding: utf-8 -*-
+"""Set received_ts using the value in updated_ts. It's not the same
+thing, but it's "close enough" for an initial value where we don't
+have anything better to base it on.
+
+This is just like 0007, but since I screwed that one up, we have to
+do it again.
+
+"""
+from __future__ import unicode_literals
+
+from datetime import datetime
+
+from django.conf import settings
+from django.db import models, migrations
+
+import pytz
+
+
+def no_op(apps, schema_editor):
+    pass
+
+
+def set_received_ts(apps, schema_editor):
+    """Sets received_ts based on updated_ts"""
+    Answer = apps.get_model('heartbeat', 'Answer')
+
+    qs = Answer.objects.filter(received_ts=datetime(2011, 9, 1, 9, 0))
+    for ans in qs:
+        # Note: Answer.updated_ts is milliseconds since epoch. We're
+        # assuming it's in UTC, so we convert it to server time.
+        dt = datetime.fromtimestamp(ans.updated_ts / 1000)
+
+        # Apply UTC
+        utc_tz = pytz.timezone('UTC')
+        dt = utc_tz.localize(dt)
+
+        # Then switch to server time
+        local_tz = pytz.timezone(settings.TIME_ZONE)
+        dt = dt.astimezone(local_tz)
+
+        ans.received_ts = dt
+        ans.save()
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('heartbeat', '0007_auto_20150305_1119'),
+    ]
+
+    operations = [
+        # Note: This can't be backed out, but for the sake of testing
+        # and convenience, we provide a no-op.
+        migrations.RunPython(set_received_ts, reverse_code=no_op),
+    ]