Files
lijiaoqiao/llm-gateway-competitors/litellm-wheel-src/litellm/proxy/middleware/prometheus_auth_middleware.py
2026-03-26 20:06:14 +08:00

74 lines
2.5 KiB
Python

"""
Prometheus Auth Middleware - Pure ASGI implementation
"""
import json
from fastapi import Request
from starlette.types import ASGIApp, Receive, Scope, Send
import litellm
from litellm.proxy._types import SpecialHeaders
from litellm.proxy.auth.user_api_key_auth import user_api_key_auth
# Cache the header name at module level to avoid repeated enum attribute access
_AUTHORIZATION_HEADER = SpecialHeaders.openai_authorization.value # "Authorization"
class PrometheusAuthMiddleware:
"""
Middleware to authenticate requests to the metrics endpoint.
By default, auth is not run on the metrics endpoint.
Enabled by setting the following in proxy_config.yaml:
```yaml
litellm_settings:
require_auth_for_metrics_endpoint: true
```
"""
def __init__(self, app: ASGIApp) -> None:
self.app = app
async def __call__(self, scope: Scope, receive: Receive, send: Send) -> None:
# Fast path: only inspect HTTP requests; pass through websocket/lifespan immediately
if scope["type"] != "http" or "/metrics" not in scope.get("path", ""):
await self.app(scope, receive, send)
return
# Only run auth if configured to do so
if litellm.require_auth_for_metrics_endpoint is True:
# Construct Request only when auth is actually needed
request = Request(scope, receive)
api_key = request.headers.get(_AUTHORIZATION_HEADER) or ""
try:
await user_api_key_auth(request=request, api_key=api_key)
except Exception as e:
# Send 401 response directly via ASGI protocol
error_message = getattr(e, "message", str(e))
body = json.dumps(
f"Unauthorized access to metrics endpoint: {error_message}"
).encode("utf-8")
await send(
{
"type": "http.response.start",
"status": 401,
"headers": [
[b"content-type", b"application/json"],
[b"content-length", str(len(body)).encode("ascii")],
],
}
)
await send(
{
"type": "http.response.body",
"body": body,
}
)
return
# Pass through to the inner application
await self.app(scope, receive, send)