try to fix memory leak

database/__init__.py

@@ -1,7 +1,7 @@
 import datetime
 
 from core.elements import MessageSession
-from database.orm import session
+from database.orm import DBSession
 from database.tables import EnabledModules, SenderInfo, TargetAdmin, CommandTriggerTime
 
 
@@ -13,6 +13,9 @@ def convert_str_to_list(s: str) -> list:
     return s.split('|')
 
 
+session = DBSession().session
+
+
 class BotDBUtil:
     class Module:
         def __init__(self, msg: [MessageSession, str]):
@@ -20,6 +23,7 @@ class BotDBUtil:
                 self.targetId = str(msg.target.targetId)
             else:
                 self.targetId = msg
+
             self.query = session.query(EnabledModules).filter_by(targetId=self.targetId).first()
             self.enable_modules_list = convert_str_to_list(self.query.enabledModules) if self.query is not None else []
             self.need_insert = True if self.query is None else False

database/orm.py

@@ -6,8 +6,13 @@ from database.tables import *
 
 DB_LINK = Config('db_path')
 
-engine = create_engine(DB_LINK)
+class DBSession:
+    def __init__(self):
+        self.engine = engine = create_engine(DB_LINK)
+        Base.metadata.create_all(bind=engine, checkfirst=True)
+        self.Session = sessionmaker()
+        self.Session.configure(bind=self.engine)
 
-Base.metadata.create_all(bind=engine, checkfirst=True)
-
-session = sessionmaker(engine)()
+    @property
+    def session(self):
+        return self.Session()

modules/wiki/orm.py

@@ -2,10 +2,13 @@ from sqlalchemy import Column, String, Text, TIMESTAMP, text
 from sqlalchemy.dialects.mysql import LONGTEXT
 from sqlalchemy.ext.declarative import declarative_base
 
-from database.orm import engine, session
+from database.orm import DBSession
 
 Base = declarative_base()
 table_prefix = 'module_wiki_'
+db = DBSession()
+session = db.session
+engine = db.engine
 
 
 class WikiTargetSetInfo(Base):