Extract shared adapter validation helpers

dns_sync/adapter_support.py

@@ -0,0 +1,41 @@
+from .adapters import Endpoint, NormalizedObject, PlanAction
+
+
+def require_endpoint_plugin(
+    endpoint: Endpoint,
+    plugin_name: str,
+) -> None:
+    expected = plugin_name.strip().lower()
+
+    if not expected:
+        raise ValueError("Adapter plugin name cannot be empty")
+
+    if endpoint.plugin != expected:
+        raise RuntimeError(
+            f"Adapter {expected!r} cannot use endpoint "
+            f"{endpoint.identity!r}"
+        )
+
+
+def require_action_endpoint(
+    action: PlanAction,
+    endpoint: Endpoint,
+) -> None:
+    if action.endpoint_id != endpoint.identity:
+        raise RuntimeError(
+            f"Plan action for {action.endpoint_id!r} does not belong "
+            f"to adapter endpoint {endpoint.identity!r}"
+        )
+
+
+def require_desired(
+    action: PlanAction,
+    *,
+    context: str = "Adapter apply",
+) -> NormalizedObject:
+    if action.desired is None:
+        raise RuntimeError(
+            f"{context} requires desired state"
+        )
+
+    return action.desired