feat: Add timing middleware

Author: alukach

src/stac_auth_proxy/app.py

@@ -11,12 +11,14 @@
 
 from .proxy import ReverseProxy
 from .config import Settings
+from .middleware import AddProcessTimeHeaderMiddleware
 
 
 def create_app(settings: Optional[Settings] = None) -> FastAPI:
     settings = settings or Settings()
 
     app = FastAPI(openapi_url=None)
+    app.add_middleware(AddProcessTimeHeaderMiddleware)
 
     open_id_connect_scheme = OpenIdConnect(
         openIdConnectUrl=str(settings.oidc_discovery_url),

src/stac_auth_proxy/middleware.py

@@ -0,0 +1,13 @@
+import time
+
+from fastapi import Request, Response
+from starlette.middleware.base import BaseHTTPMiddleware
+
+
+class AddProcessTimeHeaderMiddleware(BaseHTTPMiddleware):
+    async def dispatch(self, request: Request, call_next) -> Response:
+        start_time = time.perf_counter()
+        response = await call_next(request)
+        process_time = time.perf_counter() - start_time
+        response.headers["X-Process-Time"] = f"{process_time:.3f}"
+        return response