cache http_v2_enabled

Author: YunchuWang

azure-functions-extension-base/azure/functions/extension/base/web.py

@@ -1,19 +1,22 @@
 from abc import abstractmethod
 from enum import Enum
 import inspect
-from typing import Callable
+from typing import Callable, Optional
 
-base_extension_module = __name__
+BASE_EXTENSION_MODULE = __name__
+
+
+class Cache:
+    _http_v2_enabled: Optional[bool] = None
 
 
-# Base extension pkg
 class ModuleTrackerMeta(type):
     _module = None
 
     def __new__(cls, name, bases, dct, **kwargs):
         new_class = super().__new__(cls, name, bases, dct)
         new_module = dct.get('__module__')
-        if new_module != base_extension_module:
+        if new_module != BASE_EXTENSION_MODULE:
             if cls._module is None:
                 cls._module = new_module
             elif cls._module != new_module:
@@ -117,7 +120,9 @@ async def serve(self):
 
 
 def http_v2_enabled() -> bool:
-    return ModuleTrackerMeta.module_imported()
+    if Cache._http_v2_enabled is None:
+        Cache._http_v2_enabled = ModuleTrackerMeta.module_imported()
+    return Cache._http_v2_enabled
 
 
 class ResponseLabels(Enum):