added expiry for in-memory state store

Author: Kristian Nylund

text_2_sql/autogen/pyproject.toml

@@ -17,6 +17,7 @@ dependencies = [
     "text_2_sql_core",
     "sqlparse>=0.4.4",
     "nltk>=3.8.1",
+    "cachetools>=5.5.1",
 ]
 
 [dependency-groups]

text_2_sql/autogen/src/autogen_text_2_sql/__init__.py

@@ -1,6 +1,8 @@
 # Copyright (c) Microsoft Corporation.
 # Licensed under the MIT License.
 from autogen_text_2_sql.autogen_text_2_sql import AutoGenText2Sql
+from autogen_text_2_sql.state_store import InMemoryStateStore
+
 from text_2_sql_core.payloads.interaction_payloads import (
     UserMessagePayload,
     DismabiguationRequestsPayload,
@@ -16,4 +18,5 @@
     "AnswerWithSourcesPayload",
     "ProcessingUpdatePayload",
     "InteractionPayload",
+    "InMemoryStateStore",
 ]

text_2_sql/autogen/src/autogen_text_2_sql/state_store.py

@@ -1,4 +1,5 @@
 from abc import ABC, abstractmethod
+from cachetools import TTLCache
 
 class StateStore(ABC):
     @abstractmethod
@@ -12,8 +13,7 @@ def save_state(self, thread_id, state):
 
 class InMemoryStateStore(StateStore):
     def __init__(self):
-        # Replace with a caching library or something to have some sort of expiry for entries so this doesn't grow forever
-        self.cache = {}
+        self.cache = TTLCache(maxsize=1000, ttl=4*60*60)  # 4 hours
 
     def get_state(self, thread_id):
         return self.cache.get(thread_id)