Closes #11559: Implement config template rendering (#11769)

* WIP

* Add config_template field to Device

* Pre-fetch referenced templates

* Correct up_to_date callable

* Add config_template FK to Device

* Update & merge migrations

* Add config_template FK to Platform

* Add tagging support for ConfigTemplate

* Catch exceptions when rendering device templates in UI

* Refactor ConfigTemplate.render()

* Add support for returning plain text content

* Add ConfigTemplate model documentation

* Add feature documentation for config rendering

netbox/extras/api/serializers.py

@@ -16,6 +16,7 @@ from extras.utils import FeatureQuery
 from netbox.api.exceptions import SerializerNotFound
 from netbox.api.fields import ChoiceField, ContentTypeField, SerializedPKRelatedField
 from netbox.api.serializers import BaseModelSerializer, NetBoxModelSerializer, ValidatedModelSerializer
+from netbox.api.serializers.features import TaggableModelSerializer
 from netbox.constants import NESTED_SERIALIZER_PREFIX
 from tenancy.api.nested_serializers import NestedTenantSerializer, NestedTenantGroupSerializer
 from tenancy.models import Tenant, TenantGroup
@@ -29,6 +30,7 @@ from .nested_serializers import *
 
 __all__ = (
     'ConfigContextSerializer',
+    'ConfigTemplateSerializer',
     'ContentTypeSerializer',
     'CustomFieldSerializer',
     'CustomLinkSerializer',
@@ -383,6 +385,27 @@ class ConfigContextSerializer(ValidatedModelSerializer):
         ]
 
 
+#
+# Config templates
+#
+
+class ConfigTemplateSerializer(TaggableModelSerializer, ValidatedModelSerializer):
+    url = serializers.HyperlinkedIdentityField(view_name='extras-api:configtemplate-detail')
+    data_source = NestedDataSourceSerializer(
+        required=False
+    )
+    data_file = NestedDataFileSerializer(
+        read_only=True
+    )
+
+    class Meta:
+        model = ConfigTemplate
+        fields = [
+            'id', 'url', 'display', 'name', 'description', 'environment_params', 'template_code', 'data_source',
+            'data_path', 'data_file', 'data_synced', 'tags', 'created', 'last_updated',
+        ]
+
+
 #
 # Job Results
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