modified: netbox_services/engine/__init__.py

modified:   netbox_services/engine/allocators.py
modified:   netbox_services/engine/context.py
new file:   netbox_services/engine/mappers.py
modified:   netbox_services/engine/resolver.py
new file:   netbox_services/engine/templating.py
modified:   netbox_services/forms.py
modified:   netbox_services/models.py
modified:   netbox_services/tests/test_allocators.py
new file:   netbox_services/tests/test_mappers.py
modified:   netbox_services/tests/test_resolver.py
new file:   netbox_services/tests/test_templating.py
Simplify layout to template and service instances

netbox_services/engine/allocators.py

@@ -1,6 +1,68 @@
-"""Allocators create or acquire objects that don't exist yet (e.g. IP addresses)."""
+"""Allocators create or acquire objects that don't exist yet.
+
+Strategies:
+  - ``create``     — instantiate a new model instance from attrs (unsaved)
+  - ``first_free`` — allocate the first available IP from a prefix
+  - ``specific``   — use an existing object by address or context path
+"""
+
+from django.db.models import Model
 
 from .registry import register_allocator, get_selector
+from .templating import render_attrs
+
+
+@register_allocator("create")
+class CreateAllocator:
+    """Instantiate a new model instance from a dict of attrs.
+
+    The instance is returned **unsaved** — the resolver saves it after
+    applying the parent link (if any).
+
+    Attrs values may be:
+      - Plain literals (int, bool, list) — passed through
+      - Jinja2 strings with ``{{ }}`` — rendered with ``service``,
+        ``index``, ``p1`` (parent), ``p2`` (grandparent), etc.
+      - FK fields: the rendered value is treated as a **PK** and
+        resolved to the related model instance via ``.objects.get(pk=...)``
+
+    Spec shape::
+
+        {"strategy": "create", "attrs": {"name": "rtr-{{ service.tenant.slug }}-{{ index + 1 }}", "site": "{{ ..site.pk }}", "status": "active"}}
+    """
+
+    def __init__(self, spec):
+        self.spec = spec
+        self.attrs = spec.get("attrs", {})
+
+    def allocate(self, context, model=None, index=0, ancestors=None):
+        if model is None:
+            raise ValueError("CreateAllocator requires a model class.")
+
+        rendered = render_attrs(
+            self.attrs, context.service, ancestors or [], index,
+        )
+
+        kwargs = {}
+        for key, value in rendered.items():
+            try:
+                field = model._meta.get_field(key)
+            except Exception:
+                kwargs[key] = value
+                continue
+
+            if (
+                field.is_relation
+                and field.many_to_one
+                and not isinstance(value, Model)
+                and value is not None
+            ):
+                related = field.remote_field.model
+                kwargs[key] = related.objects.get(pk=int(value))
+            else:
+                kwargs[key] = value
+
+        return model(**kwargs)
 
 
 @register_allocator("first_free")
@@ -23,7 +85,7 @@ class FirstFreeIPAddressAllocator:
         qs = selector.resolve(context, Prefix)
         return qs.first()
 
-    def allocate(self, context):
+    def allocate(self, context, model=None, index=0, ancestors=None):
         from ipam.models import IPAddress
         from ipam.choices import IPAddressStatusChoices
 
@@ -62,7 +124,7 @@ class SpecificAllocator:
         self.path = spec.get("path")
         self.address = spec.get("address")
 
-    def allocate(self, context):
+    def allocate(self, context, model=None, index=0, ancestors=None):
         if self.address:
             from ipam.models import IPAddress
             from ipam.choices import IPAddressStatusChoices