Set primary key to UUID to fix API bug

While objects were routinely cleaned, the auto-incrementing ID field
went past the limit of IntegerField. The UUID field is unique and can
be used instead.

data_import/migrations/0025_auto_20201222_1934.py

@@ -0,0 +1,24 @@
+# Generated by Django 2.2.13 on 2020-12-22 19:34
+
+from django.db import migrations, models
+import uuid
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [("data_import", "0024_auto_20201222_1757")]
+
+    operations = [
+        migrations.RemoveField(model_name="datafilekey", name="id"),
+        migrations.AlterField(
+            model_name="datafilekey",
+            name="key",
+            field=models.CharField(
+                default=uuid.uuid4,
+                max_length=36,
+                primary_key=True,
+                serialize=False,
+                unique=True,
+            ),
+        ),
+    ]

data_import/models.py

@@ -43,7 +43,9 @@ class DataFileKey(models.Model):
     """
 
     created = models.DateTimeField(auto_now_add=True)
-    key = models.CharField(max_length=36, blank=False, unique=True, default=uuid.uuid4)
+    key = models.CharField(
+        max_length=36, blank=False, unique=True, default=uuid.uuid4, primary_key=True
+    )
     datafile_id = models.BigIntegerField()
     ip_address = models.GenericIPAddressField(null=True)
     access_token = models.CharField(max_length=64, null=True)
@@ -112,12 +114,10 @@ def generate_key(self, request):
         Generate new link expiration key
         """
         new_key = DataFileKey(datafile_id=self.id)
-        new_key.save()
 
         if request:
             # Log the entity that is requesting the key be generated
             new_key.ip_address = get_ip(request)
-            new_key.save()
 
             try:
                 new_key.access_token = request.query_params.get("access_token", None)
@@ -128,8 +128,8 @@ def generate_key(self, request):
             except AttributeError:
                 # We do not have an accessing project
                 new_key.project_id = None
-            new_key.save()
 
+        new_key.save()
         return new_key.key
 
     @property