Initial commit

netbox_services/engine/selectors.py

@@ -0,0 +1,104 @@
+"""Selectors resolve a specification into a queryset of matching NetBox objects."""
+
+import importlib
+
+from django.db.models import Q
+
+from .registry import register_selector
+
+
+def _get_filterset_for_model(model):
+    """Look up a model's FilterSet by convention: {app_label}.filtersets.{ModelName}FilterSet."""
+    app_label = model._meta.app_label
+    model_name = model._meta.model_name
+    class_name = f"{model.__name__}FilterSet"
+    try:
+        module = importlib.import_module(f"{app_label}.filtersets")
+        return getattr(module, class_name, None)
+    except (ImportError, AttributeError):
+        return None
+
+
+@register_selector("netbox_filter")
+class NetBoxFilterSelector:
+    """Select objects by applying NetBox filter parameters.
+
+    Spec shape::
+        {"type": "netbox_filter", "filters": {"role": "router", "site__in": ["hq"]}}
+    """
+
+    def __init__(self, spec):
+        self.spec = spec
+        self.filters = spec.get("filters", {})
+
+    def resolve(self, context, model):
+        qs = model.objects.all()
+        filterset_cls = _get_filterset_for_model(model)
+        if filterset_cls is not None:
+            fs = filterset_cls(self.filters, queryset=qs, request=None)
+            qs = fs.qs
+        else:
+            qs = qs.filter(**self._build_q(self.filters))
+        return qs
+
+    @staticmethod
+    def _build_q(filters):
+        """Best-effort: turn the filter dict into ORM kwargs (no fancy lookups)."""
+        return {k: v for k, v in filters.items()}
+
+
+@register_selector("reference")
+class ReferenceSelector:
+    """Select a single object via a dotted context path.
+
+    Spec shape::
+        {"type": "reference", "path": "parent.site"}
+    """
+
+    def __init__(self, spec):
+        self.spec = spec
+        self.path = spec.get("path")
+
+    def resolve(self, context, model):
+        obj = context.resolve_path(self.path)
+        if obj is None:
+            return model.objects.none()
+        if isinstance(obj, (list, tuple)):
+            return model.objects.filter(pk__in=[o.pk for o in obj])
+        return model.objects.filter(pk=obj.pk)
+
+
+@register_selector("prefix")
+class PrefixSelector:
+    """Select ipam.Prefix objects by filter or context reference.
+
+    Spec shape (filter)::
+        {"type": "prefix", "filters": {"site": "hq", "tag": "mgmt"}}
+
+    Spec shape (reference)::
+        {"type": "prefix", "path": "parent.site.management_prefix"}
+    """
+
+    def __init__(self, spec):
+        self.spec = spec
+        self.filters = spec.get("filters")
+        self.path = spec.get("path")
+
+    def resolve(self, context, model):
+        from ipam.models import Prefix
+
+        if self.path:
+            obj = context.resolve_path(self.path)
+            if obj is None:
+                return Prefix.objects.none()
+            return Prefix.objects.filter(pk=obj.pk)
+
+        if self.filters is not None:
+            filterset_cls = _get_filterset_for_model(Prefix)
+            qs = Prefix.objects.all()
+            if filterset_cls is not None:
+                fs = filterset_cls(self.filters, queryset=qs, request=None)
+                return fs.qs
+            return qs.filter(**self.filters)
+
+        return Prefix.objects.none()