Automatically create the directory path for a JSONTokenStorage (#998)

changelog.d/20240709_111157_derek_auto_create_json_token_path.rst

@@ -0,0 +1,6 @@
+
+Fixed
+~~~~~
+
+- When a JSONTokenStorage is used, the containing directory will be automatically be
+  created if it doesn't exist instead of erroring (on Mac).

src/globus_sdk/experimental/tokenstorage/json.py

@@ -1,6 +1,7 @@
 from __future__ import annotations
 
 import json
+import os
 import pathlib
 import typing as t
 
@@ -40,8 +41,15 @@ def __init__(self, filename: pathlib.Path | str, *, namespace: str = "DEFAULT"):
         :param namespace: A user-supplied namespace for partitioning token data
         """
         self.filename = str(filename)
+        self._ensure_containing_dir_exists()
         super().__init__(namespace=namespace)
 
+    def _ensure_containing_dir_exists(self) -> None:
+        """
+        Ensure that the directory containing the given filename exists.
+        """
+        os.makedirs(os.path.dirname(self.filename), exist_ok=True)
+
     def _invalid(self, msg: str) -> t.NoReturn:
         raise ValueError(
             f"{msg} while loading from '{self.filename}' for JSON Token Storage"