Add selectable PostgreSQL monitor backends

daemon/registry.py

@@ -84,6 +84,20 @@ class Plugin:
                 + ", ".join(missing)
             )
 
+        plugin_validator = getattr(
+            self.module,
+            "validate_config",
+            None,
+        )
+
+        if plugin_validator is not None:
+            try:
+                plugin_validator(config)
+            except (TypeError, ValueError) as exc:
+                raise RegistryError(
+                    f"invalid plugin configuration: {exc}"
+                ) from exc
+
     def execute(
         self,
         action,