Lazy load the executor

Author: hectorcast-db

databricks/sdk/oauth.py

@@ -205,9 +205,19 @@ class _TokenState(Enum):
 class Refreshable(TokenSource):
     """A token source that supports refreshing expired tokens."""
 
-    _EXECUTOR = ThreadPoolExecutor(max_workers=10)
+    _EXECUTOR = None
+    _EXECUTOR_LOCK = threading.Lock()
     _DEFAULT_STALE_DURATION = timedelta(minutes=3)
 
+    @classmethod
+    def _get_executor(cls):
+        """Lazy initialization of the ThreadPoolExecutor."""
+        if cls._EXECUTOR is None:
+            with cls._EXECUTOR_LOCK:
+                if cls._EXECUTOR is None:
+                    cls._EXECUTOR = ThreadPoolExecutor(max_workers=10)
+        return cls._EXECUTOR
+
     def __init__(self,
                  token: Token = None,
                  disable_async: bool = True,
@@ -289,7 +299,7 @@ def _refresh_internal():
         with self._lock:
             if not self._is_refreshing and not self._refresh_err:
                 self._is_refreshing = True
-                self._EXECUTOR.submit(_refresh_internal)
+                Refreshable._get_executor().submit(_refresh_internal)
 
     @abstractmethod
     def refresh(self) -> Token: