fix: CachingRegistry threading cache refresh (#179)

* add logging to CachingRegistry

* chore: formatting

* fix: add more logs to find what line is bringing down thread

* fix: delete added coverage files

* fix: switch to time.sleep in refresh thread

* fix: remove verbose logging and add exception handling

Author: zabarn

sdk/python/feast/infra/registry/caching_registry.py

@@ -1,6 +1,7 @@
 import atexit
 import logging
 import threading
+import time
 import warnings
 from abc import abstractmethod
 from datetime import timedelta
@@ -37,6 +38,8 @@ def __init__(self, project: str, cache_ttl_seconds: int, cache_mode: str):
         )
         self.cached_registry_proto = self.proto()
         self.cached_registry_proto_created = _utc_now()
+        self._stop_event = threading.Event()
+        logger.info(f"Registry initialized with cache mode: {cache_mode}")
         if cache_mode == "thread":
             self._start_thread_async_refresh(cache_ttl_seconds)
             atexit.register(self._exit_handler)
@@ -458,12 +461,29 @@ def _refresh_cached_registry_if_necessary(self):
     def _start_thread_async_refresh(self, cache_ttl_seconds):
         self.refresh()
         if cache_ttl_seconds <= 0:
+            logger.info("Registry cache refresh thread not started as TTL is 0")
             return
-        self.registry_refresh_thread = threading.Timer(
-            cache_ttl_seconds, self._start_thread_async_refresh, [cache_ttl_seconds]
-        )
-        self.registry_refresh_thread.daemon = True
-        self.registry_refresh_thread.start()
+
+        def refresh_loop():
+            while not self._stop_event.is_set():
+                try:
+                    time.sleep(cache_ttl_seconds)
+                    if not self._stop_event.is_set():
+                        self.refresh()
+                except Exception as e:
+                    logger.exception("Exception in refresh_loop: %s", e)
+
+        try:
+            self.registry_refresh_thread = threading.Thread(
+                target=refresh_loop, daemon=True
+            )
+            self.registry_refresh_thread.start()
+            logger.info(
+                f"Registry cache refresh thread started with TTL {cache_ttl_seconds}"
+            )
+        except Exception as e:
+            logger.exception("Failed to start registry refresh thread: %s", e)
 
     def _exit_handler(self):
-        self.registry_refresh_thread.cancel()
+        logger.info("Exiting, setting stop event for registry cache refresh thread")
+        self._stop_event.set()