Make HostingOrder not mandatory in MonthlyHostingBill

hosting/migrations/0053_auto_20190415_1952.py

@@ -0,0 +1,21 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.9.4 on 2019-04-15 19:52
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('hosting', '0052_hostingbilllineitem'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='monthlyhostingbill',
+            name='order',
+            field=models.ForeignKey(blank=True, default=None, null=True, on_delete=django.db.models.deletion.SET_NULL, to='hosting.HostingOrder'),
+        ),
+    ]

hosting/models.py

@@ -240,7 +240,10 @@ class MonthlyHostingBill(AssignPermissionsMixin, models.Model):
     Corresponds to Invoice object of Stripe
     """
     customer = models.ForeignKey(StripeCustomer)
-    order = models.ForeignKey(HostingOrder)
+    order = models.ForeignKey(
+        HostingOrder, null=True, blank=True, default=None,
+        on_delete=models.SET_NULL
+    )
     created = models.DateTimeField(help_text="When the invoice was created")
     receipt_number = models.CharField(
         help_text="The receipt number that is generated on Stripe",
@@ -274,9 +277,15 @@ class MonthlyHostingBill(AssignPermissionsMixin, models.Model):
         if len(args['subscription_ids_csv']) > 0:
             sub_ids = [sub_id.strip() for sub_id in args['subscription_ids_csv'].split(",")]
             if len(sub_ids) == 1:
-                args['order'] = HostingOrder.objects.get(
-                    subscription_id=sub_ids[0]
-                )
+                try:
+                    args['order'] = HostingOrder.objects.get(
+                        subscription_id=sub_ids[0]
+                    )
+                except HostingOrder.DoesNotExist as dne:
+                    logger.error("Hosting order for {} doesn't exist".format(
+                        sub_ids[0]
+                    ))
+                    args['order'] = None
             else:
                 logger.debug(
                     "More than one subscriptions"