chore: Update FDv2 memory store to be atomic

Author: keelerm84

ldclient/client.py

@@ -53,7 +53,8 @@
     DataStoreStatusProvider,
     DataStoreUpdateSink,
     FeatureStore,
-    FlagTracker
+    FlagTracker,
+    ReadOnlyStore
 )
 from ldclient.migrations import OpTracker, Stage
 from ldclient.plugin import (
@@ -272,7 +273,7 @@ def __start_up(self, start_wait: float):
             self._data_system.data_source_status_provider
         )
         self.__flag_tracker = self._data_system.flag_tracker
-        self._store: FeatureStore = self._data_system.store  # type: ignore
+        self._store: ReadOnlyStore = self._data_system.store
 
         big_segment_store_manager = BigSegmentStoreManager(self._config.big_segments)
         self.__big_segment_store_manager = big_segment_store_manager

ldclient/impl/datasystem/__init__.py

@@ -16,7 +16,8 @@
     DataSourceState,
     DataSourceStatusProvider,
     DataStoreStatusProvider,
-    FlagTracker
+    FlagTracker,
+    ReadOnlyStore
 )
 
 
@@ -141,6 +142,14 @@ def target_availability(self) -> DataAvailability:
         """
         raise NotImplementedError
 
+    @property
+    @abstractmethod
+    def store(self) -> ReadOnlyStore:
+        """
+        Returns the data store used by the data system.
+        """
+        raise NotImplementedError
+
 
 class SelectorStore(Protocol):
     """

ldclient/impl/datasystem/fdv1.py

@@ -24,6 +24,7 @@
     DataStoreStatusProvider,
     FeatureStore,
     FlagTracker,
+    ReadOnlyStore,
     UpdateProcessor
 )
 
@@ -110,7 +111,7 @@ def stop(self):
             self._update_processor.stop()
 
     @property
-    def store(self) -> FeatureStore:
+    def store(self) -> ReadOnlyStore:
         return self._store_wrapper
 
     def set_flag_value_eval_fn(self, eval_fn):

ldclient/impl/datasystem/fdv2.py

@@ -24,7 +24,8 @@
     DataStoreStatus,
     DataStoreStatusProvider,
     FeatureStore,
-    FlagTracker
+    FlagTracker,
+    ReadOnlyStore
 )
 from ldclient.versioned_data_kind import VersionedDataKind
 
@@ -500,7 +501,7 @@ def _recovery_condition(self, status: DataSourceStatus) -> bool:
         return interrupted_at_runtime or healthy_for_too_long or cannot_initialize
 
     @property
-    def store(self) -> FeatureStore:
+    def store(self) -> ReadOnlyStore:
         """Get the underlying store for flag evaluation."""
         return self._store.get_active_store()
 

ldclient/impl/datasystem/protocolv2.py

@@ -458,9 +458,7 @@ class Change:
     kind: ObjectKind
     key: str
     version: int
-    object: Any = (
-        None  # TODO(fdv2): At some point, we should define a better type for this.
-    )
+    object: Optional[dict] = None
 
 
 @dataclass(frozen=True)