fix: Offline handler not used as fallback for local evaluation mode during init (#100)

Author: khvn26

flagsmith/flagsmith.py

@@ -159,8 +159,10 @@ def __init__(
                 )
 
     def _initialise_local_evaluation(self) -> None:
+        # To ensure that the environment is set before allowing subsequent
+        # method calls, update the environment manually.
+        self.update_environment()
         if self.enable_realtime_updates:
-            self.update_environment()
             if not self._environment:
                 raise ValueError("Unable to get environment from API key")
 
@@ -175,9 +177,6 @@ def _initialise_local_evaluation(self) -> None:
             self.event_stream_thread.start()
 
         else:
-            # To ensure that the environment is set before allowing subsequent
-            # method calls, update the environment manually.
-            self.update_environment()
             self.environment_data_polling_manager_thread = (
                 EnvironmentDataPollingManager(
                     main=self,
@@ -281,7 +280,10 @@ def get_identity_segments(
         return [Segment(id=sm.id, name=sm.name) for sm in segment_models]
 
     def update_environment(self) -> None:
-        self._environment = self._get_environment_from_api()
+        try:
+            self._environment = self._get_environment_from_api()
+        except (FlagsmithAPIError, requests.RequestException):
+            logger.exception("Error updating environment")
         self._update_overrides()
 
     def _update_overrides(self) -> None:

flagsmith/polling_manager.py

@@ -5,10 +5,6 @@
 import time
 import typing
 
-import requests
-
-from flagsmith.exceptions import FlagsmithAPIError
-
 if typing.TYPE_CHECKING:
     from flagsmith import Flagsmith
 
@@ -30,10 +26,7 @@ def __init__(
 
     def run(self) -> None:
         while not self._stop_event.is_set():
-            try:
-                self.main.update_environment()
-            except (FlagsmithAPIError, requests.RequestException):
-                logger.exception("Failed to update environment")
+            self.main.update_environment()
             time.sleep(self.refresh_interval_seconds)
 
     def stop(self) -> None:

flagsmith/streaming_manager.py

@@ -1,15 +1,10 @@
-import logging
 import threading
 import typing
 from typing import Callable, Generator, Optional, Protocol, cast
 
 import requests
 import sseclient
 
-from flagsmith.exceptions import FlagsmithAPIError
-
-logger = logging.getLogger(__name__)
-
 
 class StreamEvent(Protocol):
     data: str
@@ -48,9 +43,6 @@ def run(self) -> None:
             except requests.exceptions.ReadTimeout:
                 pass
 
-            except (FlagsmithAPIError, requests.RequestException):
-                logger.exception("Error handling event stream")
-
     def stop(self) -> None:
         self._stop_event.set()
 

tests/test_flagsmith.py

@@ -526,6 +526,44 @@ def test_flagsmith_uses_offline_handler_if_set_and_no_api_response(
     assert identity_flags.get_feature_value("some_feature") == "some-value"
 
 
+@responses.activate()
+def test_offline_mode__local_evaluation__correct_fallback(
+    mocker: MockerFixture,
+    environment_model: EnvironmentModel,
+    caplog: pytest.LogCaptureFixture,
+) -> None:
+    # Given
+    api_url = "http://some.flagsmith.com/api/v1/"
+    mock_offline_handler = mocker.MagicMock(spec=BaseOfflineHandler)
+    mock_offline_handler.get_environment.return_value = environment_model
+
+    flagsmith = Flagsmith(
+        environment_key="ser.some-key",
+        api_url=api_url,
+        enable_local_evaluation=True,
+        offline_handler=mock_offline_handler,
+    )
+
+    responses.get(flagsmith.environment_url, status=500)
+
+    # When
+    environment_flags = flagsmith.get_environment_flags()
+    identity_flags = flagsmith.get_identity_flags("identity", traits={})
+
+    # Then
+    mock_offline_handler.get_environment.assert_called_once_with()
+
+    assert environment_flags.is_feature_enabled("some_feature") is True
+    assert environment_flags.get_feature_value("some_feature") == "some-value"
+
+    assert identity_flags.is_feature_enabled("some_feature") is True
+    assert identity_flags.get_feature_value("some_feature") == "some-value"
+
+    [error_log_record] = caplog.records
+    assert error_log_record.levelname == "ERROR"
+    assert error_log_record.message == "Error updating environment"
+
+
 def test_cannot_use_offline_mode_without_offline_handler() -> None:
     with pytest.raises(ValueError) as e:
         # When

tests/test_streaming_manager.py

@@ -36,36 +36,6 @@ def test_stream_manager_handles_timeout(
     streaming_manager.stop()
 
 
-def test_stream_manager_handles_request_exception(
-    mocked_responses: responses.RequestsMock,
-    caplog: pytest.LogCaptureFixture,
-) -> None:
-    stream_url = (
-        "https://realtime.flagsmith.com/sse/environments/B62qaMZNwfiqT76p38ggrQ/stream"
-    )
-
-    mocked_responses.get(stream_url, body=requests.RequestException())
-    mocked_responses.get(stream_url, body=FlagsmithAPIError())
-
-    streaming_manager = EventStreamManager(
-        stream_url=stream_url,
-        on_event=MagicMock(),
-        daemon=True,
-    )
-
-    streaming_manager.start()
-
-    time.sleep(0.01)
-
-    assert streaming_manager.is_alive()
-
-    streaming_manager.stop()
-
-    for record in caplog.records:
-        assert record.levelname == "ERROR"
-        assert record.message == "Error handling event stream"
-
-
 def test_environment_updates_on_recent_event(
     server_api_key: str, mocker: MockerFixture
 ) -> None: