Address middleware compatibility issue on FastAPI

Author: vishalbollu

pkg/workloads/cortex/serve/serve.py

@@ -25,11 +25,13 @@
 
 from fastapi import Body, FastAPI
 from fastapi.exceptions import RequestValidationError
-from fastapi.middleware.cors import CORSMiddleware
 from starlette.requests import Request
 from starlette.responses import Response
 from starlette.background import BackgroundTasks
 from starlette.exceptions import HTTPException as StarletteHTTPException
+from starlette.applications import Starlette
+from starlette.middleware import Middleware
+from starlette.middleware.cors import CORSMiddleware
 
 from cortex import consts
 from cortex.lib import util
@@ -55,15 +57,17 @@
     ThreadPoolExecutor(max_workers=int(os.environ["CORTEX_THREADS_PER_WORKER"]))
 )
 
-app = FastAPI()
-
-app.add_middleware(
-    CORSMiddleware,
-    allow_origins=["*"],
-    allow_credentials=True,
-    allow_methods=["*"],
-    allow_headers=["*"],
-)
+middleware = [
+    Middleware(
+        CORSMiddleware,
+        allow_origins=["*"],
+        allow_credentials=True,
+        allow_methods=["*"],
+        allow_headers=["*"],
+    )
+]
+
+app = FastAPI(middleware=middleware)
 
 local_cache = {"api": None, "predictor_impl": None, "client": None, "class_set": set()}