refactor: create redis fields before altering

instance/migrations/0143_add_redis_server.py

@@ -7,15 +7,6 @@
 import instance.models.utils
 
 
-def generate_credentials(apps, schema_editor):
-    RedisServer = apps.get_model('instance', 'RedisServer')
-    for row in RedisServer.objects.all():
-        row.redis_username = instance.models.mixins.redis.random_username()
-        row.redis_password = instance.models.mixins.redis.random_password()
-        row.save(update_fields=['redis_username', 'redis_password'])
-
-
-
 class Migration(migrations.Migration):
 
     dependencies = [
@@ -64,15 +55,4 @@ class Migration(migrations.Migration):
             name='redis_server',
             field=models.ForeignKey(blank=True, default=instance.models.mixins.redis.select_random_redis_server, null=True, on_delete=django.db.models.deletion.PROTECT, to='instance.RedisServer'),
         ),
-        migrations.RunPython(generate_credentials, reverse_code=migrations.RunPython.noop),
-        migrations.AlterField(
-            model_name='openedxinstance',
-            name='redis_username',
-            field=models.CharField(max_length=32, unique=True),
-        ),
-        migrations.AlterField(
-            model_name='openedxinstance',
-            name='redis_password',
-            field=models.CharField(max_length=64, null=False),
-        ),
     ]

instance/migrations/0144_make_redis_username_unique.py

@@ -0,0 +1,37 @@
+# Generated by Django 2.2.24 on 2021-08-13 08:53
+
+from django.db import migrations, models
+import django.db.models.deletion
+import django_extensions.db.fields
+import instance.models.mixins.redis
+import instance.models.utils
+
+
+def generate_credentials(apps, schema_editor):
+    RedisServer = apps.get_model('instance', 'RedisServer')
+    for row in RedisServer.objects.all():
+        row.redis_username = instance.models.mixins.redis.random_username()
+        row.redis_password = instance.models.mixins.redis.random_password()
+        row.save(update_fields=['redis_username', 'redis_password'])
+
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('instance', '0143_add_redis_server'),
+    ]
+
+    operations = [
+        migrations.RunPython(generate_credentials, reverse_code=migrations.RunPython.noop),
+        migrations.AlterField(
+            model_name='openedxinstance',
+            name='redis_username',
+            field=models.CharField(max_length=32, unique=True),
+        ),
+        migrations.AlterField(
+            model_name='openedxinstance',
+            name='redis_password',
+            field=models.CharField(max_length=64, null=False),
+        ),
+    ]