fix: Stop FeatureStoreClientWrapper poller on close

ldclient/impl/datasystem/fdv2.py

@@ -228,6 +228,18 @@ def is_monitoring_enabled(self) -> bool:
             return False
 
         return monitoring_enabled()
+
+    def close(self):
+        """
+        Close the wrapper and stop the repeating task poller if it's running.
+        Also forwards the close call to the underlying store if it has a close method.
+        """
+        with self.__lock.write():
+            if self.__poller is not None:
+                self.__poller.stop()
+                self.__poller = None
+            if hasattr(self.store, "close"):
+                self.store.close()
 
 
 class FDv2(DataSystem):

ldclient/impl/datasystem/store.py

@@ -6,7 +6,6 @@
 ChangeSet applications and flag change notifications.
 """
 
-import threading
 from collections import defaultdict
 from typing import Any, Callable, Dict, List, Optional, Set
 
@@ -194,7 +193,7 @@ def __init__(
         self._selector = Selector.no_selector()
 
         # Thread synchronization
-        self._lock = threading.RLock()
+        self._lock = ReadWriteLock()
 
     def with_persistence(
         self,
@@ -213,7 +212,7 @@ def with_persistence(
         Returns:
             Self for method chaining
         """
-        with self._lock:
+        with self._lock.write():
             self._persistent_store = persistent_store
             self._persistent_store_writable = writable
             self._persistent_store_status_provider = status_provider
@@ -225,12 +224,12 @@ def with_persistence(
 
     def selector(self) -> Selector:
         """Returns the current selector."""
-        with self._lock:
+        with self._lock.read():
             return self._selector
 
     def close(self) -> Optional[Exception]:
         """Close the store and any persistent store if configured."""
-        with self._lock:
+        with self._lock.write():
             if self._persistent_store is not None:
                 try:
                     # Most FeatureStore implementations don't have close methods
@@ -251,7 +250,7 @@ def apply(self, change_set: ChangeSet, persist: bool) -> None:
         """
         collections = self._changes_to_store_data(change_set.changes)
 
-        with self._lock:
+        with self._lock.write():
             try:
                 if change_set.intent_code == IntentCode.TRANSFER_FULL:
                     self._set_basis(collections, change_set.selector, persist)
@@ -443,7 +442,7 @@ def __mapping(data: Dict[str, ModelEntity]) -> Dict[str, Dict[str, Any]]:
 
             return __mapping
 
-        with self._lock:
+        with self._lock.write():
             if self._should_persist():
                 try:
                     # Get all data from memory store and write to persistent store
@@ -457,7 +456,7 @@ def __mapping(data: Dict[str, ModelEntity]) -> Dict[str, Dict[str, Any]]:
 
     def get_active_store(self) -> ReadOnlyStore:
         """Get the currently active store for reading data."""
-        with self._lock:
+        with self._lock.read():
             return self._active_store
 
     def is_initialized(self) -> bool:
@@ -466,5 +465,5 @@ def is_initialized(self) -> bool:
 
     def get_data_store_status_provider(self) -> Optional[DataStoreStatusProvider]:
         """Get the data store status provider for the persistent store, if configured."""
-        with self._lock:
+        with self._lock.read():
             return self._persistent_store_status_provider

ldclient/interfaces.py

@@ -189,6 +189,28 @@ def initialized(self) -> bool:
     #     :return: true if the underlying data store is reachable
     #     """
 
+    # WARN: This isn't a required method on a FeatureStore. The SDK will
+    # check if the provided store responds to this method, and if it does,
+    # will call it during shutdown to release any resources (such as database
+    # connections or connection pools) that the store may be using.
+    #
+    # @abstractmethod
+    # def close(self):
+    #     """
+    #     Releases any resources used by the data store implementation.
+    #
+    #     This method will be called by the SDK during shutdown to ensure proper
+    #     cleanup of resources such as database connections, connection pools,
+    #     network sockets, or other resources that should be explicitly released.
+    #
+    #     Implementations should be idempotent - calling close() multiple times
+    #     should be safe and have no additional effect after the first call.
+    #
+    #     This is particularly important for persistent data stores that maintain
+    #     connection pools or other long-lived resources that should be properly
+    #     cleaned up when the SDK is shut down.
+    #     """
+
 
 class FeatureStoreCore:
     """