feat: add thread safety to local cache (#224)

- thread safety in LocalLRUCache since by default the cachetools classes
are not threadsafe:
https://cachetools.readthedocs.io/en/latest/#cache-implementations
- option to clear all instances in singleton metaclass

---------

Signed-off-by: Avik Basu <[email protected]>

numalogic/registry/localcache.py

@@ -10,6 +10,7 @@
 # limitations under the License.
 
 from copy import deepcopy
+from threading import Lock
 from typing import Optional
 
 from cachetools import TTLCache
@@ -19,7 +20,7 @@
 
 
 class LocalLRUCache(ArtifactCache, metaclass=Singleton):
- r"""A local in-memory LRU cache with per item Time-to-live support.
+ r"""A local in-memory LRU cache registry with per artifact Time-to-live support.
 
  Args:
  ----
@@ -34,6 +35,7 @@ def __init__(self, cachesize: int = 512, ttl: int = 300):
  super().__init__(cachesize, ttl)
  if not self.__cache:
  self.__cache = TTLCache(maxsize=cachesize, ttl=ttl)
+ self.__lock = Lock()
 
  def __contains__(self, artifact_key: str) -> bool:
  """Check if an artifact is in the cache."""
@@ -51,7 +53,8 @@ def load(self, artifact_key: str) -> Optional[ArtifactData]:
  -------
  The artifact data instance if found, None otherwise.
  """
- return self.__cache.get(artifact_key)
+ with self.__lock:
+ return self.__cache.get(artifact_key)
 
  def save(self, key: str, artifact: ArtifactData) -> None:
  """
@@ -64,7 +67,8 @@ def save(self, key: str, artifact: ArtifactData) -> None:
  """
  artifact = deepcopy(artifact)
  artifact.extras["source"] = self._STORETYPE
- self.__cache[key] = artifact
+ with self.__lock:
+ self.__cache[key] = artifact
 
  def delete(self, key: str) -> Optional[ArtifactData]:
  """
@@ -78,11 +82,13 @@ def delete(self, key: str) -> Optional[ArtifactData]:
  -------
  The deleted artifact data instance if found, None otherwise.
  """
- return self.__cache.pop(key, default=None)
+ with self.__lock:
+ return self.__cache.pop(key, default=None)
 
  def clear(self) -> None:
  """Clears the whole cache."""
- self.__cache.clear()
+ with self.__lock:
+ self.__cache.clear()
 
  def keys(self) -> list[str]:
  """Returns the current keys of the cache."""

numalogic/tools/types.py

@@ -49,3 +49,7 @@ def __call__(cls, *args, **kwargs):
  if cls not in cls._instances:
  cls._instances[cls] = super().__call__(*args, **kwargs)
  return cls._instances[cls]
+
+ @classmethod
+ def clear_instances(cls):
+ cls._instances = {}