Python: T7740: Update dict_search to return optional default value

python/vyos/utils/dict.py

@@ -145,24 +145,33 @@ def get_sub_dict(source, lpath, get_first_key=False):
 
     return ret
 
-def dict_search(path, dict_object):
+def dict_search(path, dict_object, default=None):
     """ Traverse Python dictionary (dict_object) delimited by dot (.).
-    Return value of key if found, None otherwise.
+
+    Args:
+        path (str): Dot-delimited key path, e.g. "foo.bar.baz".
+        dict_object (dict): The dictionary to search.
+        default (Any, optional): Value to return if the path is not found
+            or if dict_object is not a dict. Defaults to None.
+
+    Returns:
+        Any: The value found at the given path, or None if not found. Optionally,
+            a default value can be provided to be returned.
 
     This is faster implementation then jmespath.search('foo.bar', dict_object)"""
     if not isinstance(dict_object, dict) or not path:
-        return None
+        return default
 
     parts = path.split('.')
     inside = parts[:-1]
     if not inside:
         if path not in dict_object:
-            return None
+            return default
         return dict_object[path]
     c = dict_object
     for p in parts[:-1]:
         c = c.get(p, {})
-    return c.get(parts[-1], None)
+    return c.get(parts[-1], default)
 
 def dict_search_args(dict_object, *path):
     # Traverse dictionary using variable arguments

src/tests/test_dict_search.py

@@ -44,6 +44,14 @@ def test_non_existing_keys(self):
         self.assertEqual(dict_search('non_existing', data), None)
         self.assertEqual(dict_search('non.existing.fancy.key', data), None)
 
+    def test_non_existing_keys_with_default_positional(self):
+        # TestDictSearch: Return a default value when querying for non-existent key (positional arg)
+        self.assertEqual(dict_search('non.existing.fancy.key', data, 'test'), 'test')
+
+    def test_non_existing_keys_with_default_named(self):
+        # TestDictSearch: Return a default value when querying for non-existent key (named arg)
+        self.assertEqual(dict_search('non.existing.fancy.key', data, default='test'), 'test')
+
     def test_string(self):
         # TestDictSearch: Return value when querying string
         self.assertEqual(dict_search('string', data), data['string'])