[Del]remove Singleton

vnpy/trader/engine.py

@@ -24,7 +24,7 @@ from .event import (
 from .gateway import BaseGateway
 from .object import CancelRequest, LogData, OrderRequest, SubscribeRequest
 from .setting import SETTINGS
-from .utility import Singleton, get_folder_path
+from .utility import get_folder_path
 
 
 class MainEngine:
@@ -197,7 +197,7 @@ class BaseEngine(ABC):
         pass
 
 
-class LogEngine(BaseEngine, metaclass=Singleton):
+class LogEngine(BaseEngine):
     """
     Processes log event and output with logging module.
     """

vnpy/trader/utility.py

@@ -12,25 +12,6 @@ import talib
 from .object import BarData, TickData
 
 
-class Singleton(type):
-    """
-    Singleton metaclass,
-
-    usage:
-    class A(metaclass=Singleton):
-        ...
-    """
-    _instances = {}
-
-    def __call__(cls, *args, **kwargs):
-        """"""
-        if cls not in cls._instances:
-            cls._instances[cls] = super(Singleton, cls).__call__(
-                *args, **kwargs
-            )
-        return cls._instances[cls]
-
-
 def _get_trader_dir(temp_name: str):
     """
     Get path where trader is running in.