feat: add function to retrieve object by path

Signed-off-by: Nikita Pivkin <[email protected]>

lib/cloud/metadata.rego

@@ -0,0 +1,19 @@
+# METADATA
+# custom:
+#   library: true
+package lib.cloud.metadata
+
+import rego.v1
+
+# Returns the object found by the given path
+# if child object is not found, returns the last found object
+obj_by_path(obj, str_path) := res if {
+	path := split(str_path, ".")
+	occurrenses := {obj_path: child_object |
+		walk(obj, [obj_path, child_object])
+		child_object.__defsec_metadata
+		object.subset(path, obj_path)
+	}
+
+	res := occurrenses[max(object.keys(occurrenses))]
+} else := obj

lib/cloud/metadata_test.rego

@@ -0,0 +1,34 @@
+package lib.cloud.metadata_test
+
+import rego.v1
+
+import data.lib.cloud.metadata
+
+test_obj_by_path_happy if {
+	bar := with_meta({"value": 1})
+	obj := with_meta({"foo": with_meta({"bar": bar})})
+
+	metadata.obj_by_path(obj, "foo.bar") == bar
+}
+
+test_obj_by_path_when_target_not_found_then_return_last_found if {
+	foo := with_meta({"bar": with_meta({"value": 1})})
+	obj := with_meta({"foo": foo})
+
+	metadata.obj_by_path(obj, "foo.baz") == foo
+}
+
+test_obj_by_path_when_target_not_found_then_return_obj if {
+	foo := with_meta({"bar": with_meta({"value": 1})})
+	obj := with_meta({"foo": foo})
+
+	metadata.obj_by_path(obj, "baz") == obj
+}
+
+test_obj_by_path_skip_without_metadata if {
+	obj := with_meta({"foo": {"bar": with_meta({"value": 1})}})
+
+	metadata.obj_by_path(obj, "foo.baz") == obj
+}
+
+with_meta(obj) := object.union(obj, {"__defsec_metadata": {}})