From b5b18278934847dc7fe8b90fabf889808d094586 Mon Sep 17 00:00:00 2001
From: Arthur <worldnomad@gmail.com>
Date: Tue, 25 Mar 2025 13:04:06 -0700
Subject: [PATCH] 18981 Make Device Roles Hierarchical

---
 netbox/dcim/graphql/types.py                  |  2 +
 .../migrations/0203_device_role_nested.py     | 56 +++++++++++++++++++
 .../migrations/0204_device_role_rebuild.py    | 22 ++++++++
 netbox/dcim/models/devices.py                 | 11 +++-
 4 files changed, 90 insertions(+), 1 deletion(-)
 create mode 100644 netbox/dcim/migrations/0203_device_role_nested.py
 create mode 100644 netbox/dcim/migrations/0204_device_role_rebuild.py

diff --git a/netbox/dcim/graphql/types.py b/netbox/dcim/graphql/types.py
index 9554a9f60..24fa16263 100644
--- a/netbox/dcim/graphql/types.py
+++ b/netbox/dcim/graphql/types.py
@@ -338,6 +338,8 @@ class InventoryItemTemplateType(ComponentTemplateType):
     pagination=True
 )
 class DeviceRoleType(OrganizationalObjectType):
+    parent: Annotated['DeviceRoleType', strawberry.lazy('dcim.graphql.types')] | None
+    children: List[Annotated['DeviceRoleType', strawberry.lazy('dcim.graphql.types')]]
     color: str
     config_template: Annotated["ConfigTemplateType", strawberry.lazy('extras.graphql.types')] | None
 
diff --git a/netbox/dcim/migrations/0203_device_role_nested.py b/netbox/dcim/migrations/0203_device_role_nested.py
new file mode 100644
index 000000000..c935f789f
--- /dev/null
+++ b/netbox/dcim/migrations/0203_device_role_nested.py
@@ -0,0 +1,56 @@
+# Generated by Django 5.1.7 on 2025-03-25 18:06
+
+import django.db.models.manager
+import mptt.fields
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('dcim', '0202_location_comments_region_comments_sitegroup_comments'),
+    ]
+
+    operations = [
+        migrations.AlterModelManagers(
+            name='devicerole',
+            managers=[
+                ('_tree_manager', django.db.models.manager.Manager()),
+            ],
+        ),
+        migrations.AddField(
+            model_name='devicerole',
+            name='level',
+            field=models.PositiveIntegerField(default=0, editable=False),
+            preserve_default=False,
+        ),
+        migrations.AddField(
+            model_name='devicerole',
+            name='lft',
+            field=models.PositiveIntegerField(default=0, editable=False),
+            preserve_default=False,
+        ),
+        migrations.AddField(
+            model_name='devicerole',
+            name='rght',
+            field=models.PositiveIntegerField(default=0, editable=False),
+            preserve_default=False,
+        ),
+        migrations.AddField(
+            model_name='devicerole',
+            name='tree_id',
+            field=models.PositiveIntegerField(db_index=True, default=0, editable=False),
+            preserve_default=False,
+        ),
+        migrations.AddField(
+            model_name='devicerole',
+            name='parent',
+            field=mptt.fields.TreeForeignKey(
+                blank=True,
+                null=True,
+                on_delete=django.db.models.deletion.CASCADE,
+                related_name='children',
+                to='dcim.devicerole',
+            ),
+        ),
+    ]
diff --git a/netbox/dcim/migrations/0204_device_role_rebuild.py b/netbox/dcim/migrations/0204_device_role_rebuild.py
new file mode 100644
index 000000000..69837c522
--- /dev/null
+++ b/netbox/dcim/migrations/0204_device_role_rebuild.py
@@ -0,0 +1,22 @@
+from django.db import migrations
+import mptt
+import mptt.managers
+
+
+def rebuild_mptt(apps, schema_editor):
+    manager = mptt.managers.TreeManager()
+    DeviceRole = apps.get_model('dcim', 'DeviceRole')
+    manager.model = DeviceRole
+    mptt.register(DeviceRole)
+    manager.contribute_to_class(DeviceRole, 'objects')
+    manager.rebuild()
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ('dcim', '0203_device_role_nested'),
+    ]
+
+    operations = [
+        migrations.RunPython(code=rebuild_mptt, reverse_code=migrations.RunPython.noop),
+    ]
diff --git a/netbox/dcim/models/devices.py b/netbox/dcim/models/devices.py
index 2acd98801..601eb770d 100644
--- a/netbox/dcim/models/devices.py
+++ b/netbox/dcim/models/devices.py
@@ -21,6 +21,7 @@ from dcim.constants import *
 from dcim.fields import MACAddressField
 from extras.models import ConfigContextModel, CustomField
 from extras.querysets import ConfigContextModelQuerySet
+from mptt.models import MPTTModel, TreeForeignKey
 from netbox.choices import ColorChoices
 from netbox.config import ConfigItem
 from netbox.models import OrganizationalModel, PrimaryModel
@@ -468,12 +469,20 @@ class ModuleType(ImageAttachmentsMixin, PrimaryModel, WeightMixin):
 # Devices
 #
 
-class DeviceRole(OrganizationalModel):
+class DeviceRole(OrganizationalModel, MPTTModel):
     """
     Devices are organized by functional role; for example, "Core Switch" or "File Server". Each DeviceRole is assigned a
     color to be used when displaying rack elevations. The vm_role field determines whether the role is applicable to
     virtual machines as well.
     """
+    parent = TreeForeignKey(
+        to='self',
+        on_delete=models.CASCADE,
+        related_name='children',
+        blank=True,
+        null=True,
+        db_index=True
+    )
     color = ColorField(
         verbose_name=_('color'),
         default=ColorChoices.COLOR_GREY