🐛 fix(manager.py): change threading.Lock to threading.RLock to allow reentrant locking and prevent deadlocks

🔀 merge(manager.py): refactor _get method to extract logic into _get_without_lock method for code reuse and readability
🔀 merge(manager.py): refactor set method to use _get_without_lock method for code reuse and readability
🔀 merge(manager.py): add lock acquisition in delete method to ensure thread safety
🔀 merge(utils.py): add update_cache method to Memoize class for updating cache values

src/backend/langflow/services/cache/manager.py

@@ -43,7 +43,7 @@ class InMemoryCache(BaseCacheManager):
             expiration_time (int, optional): Time in seconds after which a cached item expires. Default is 1 hour.
         """
         self._cache = OrderedDict()
-        self._lock = threading.Lock()
+        self._lock = threading.RLock()
         self.max_size = max_size
         self.expiration_time = expiration_time
 
@@ -58,14 +58,19 @@ class InMemoryCache(BaseCacheManager):
             The value associated with the key, or None if the key is not found or the item has expired.
         """
         with self._lock:
-            if key in self._cache:
+            return self._get_without_lock(key)
-                item = self._cache.pop(key)
+
+    def _get_without_lock(self, key):
+        """
+        Retrieve an item from the cache without acquiring the lock.
+        """
+        if item := self._cache.get(key):
             if (
                 self.expiration_time is None
                 or time.time() - item["time"] < self.expiration_time
             ):
                 # Move the key to the end to make it recently used
-                    self._cache[key] = item
+                self._cache.move_to_end(key)
                 return item["value"]
             else:
                 self.delete(key)
@@ -100,7 +105,7 @@ class InMemoryCache(BaseCacheManager):
             value: The value to insert or update.
         """
         with self._lock:
-            existing_value = self.get(key)
+            existing_value = self._get_without_lock(key)
             if (
                 existing_value is not None
                 and isinstance(existing_value, dict)
@@ -135,7 +140,7 @@ class InMemoryCache(BaseCacheManager):
         Args:
             key: The key of the item to remove.
         """
-        # with self._lock:
+        with self._lock:
             self._cache.pop(key, None)
 
     def clear(self):

src/backend/langflow/services/cache/utils.py

@@ -212,6 +212,10 @@ class Memoize:
         cache_manager = self.get_cache_manager()
         return cache_manager.get(session_id)
 
+    def update_cache(self, session_id, value):
+        cache_manager = self.get_cache_manager()
+        cache_manager.set(session_id, value)
+
     def __call__(self, func: Callable[..., Any]):
         @functools.wraps(func)
         def wrapper(*args, **kwargs):
@@ -228,5 +232,6 @@ class Memoize:
             return result
 
         wrapper.clear_cache = self.clear_cache
+        wrapper.update_cache = self.update_cache
         wrapper.get_result_by_session_id = self.get_result_by_session_id
         return wrapper