Merge branch 'main' into logo

Author: luis5tb

docs/rate-limiting.md

@@ -182,4 +182,5 @@ Rate limiting happens **before** the request is processed (at the middleware lay
 
 - Rate limits are enforced across replicas as long as they share the same Redis instance.
 - The service verifies Redis connectivity at startup and fails fast when Redis is unavailable.
+- **Fail-open behaviour**: If Redis becomes unreachable at runtime, requests are allowed through without rate limiting (with a warning log). This prevents a Redis outage from causing a self-inflicted denial of service.
 - **In-transit encryption (TLS)**: Cloud Memorystore instances are created with `--transit-encryption-mode=SERVER_AUTHENTICATION`. Use the `rediss://` URL scheme and set `RATE_LIMIT_REDIS_CA_CERT` to the path of the mounted server CA certificate. See [Cloud Run Deployment — Redis Setup](../deploy/cloudrun/README.md#4-redis-setup-for-rate-limiting) for setup instructions.

src/lightspeed_agent/ratelimit/middleware.py

@@ -271,17 +271,16 @@ async def dispatch(
         try:
             allowed, status = await self._limiter.is_allowed(principal_keys=principals)
         except RuntimeError:
-            logger.error(
-                "Rate limiter backend unavailable, returning 503 (principals=%s)",
+            # Fail open: allow the request through when Redis is unavailable.
+            # Blocking all traffic on a rate-limiter outage would be a
+            # self-inflicted denial of service.
+            logger.warning(
+                "Rate limiter backend unavailable, allowing request (fail-open). "
+                "principals=%s",
                 principals,
             )
-            return JSONResponse(
-                status_code=503,
-                content={
-                    "error": "rate_limiter_unavailable",
-                    "message": "Rate limiter backend unavailable",
-                },
-            )
+            response = await call_next(request)
+            return response
 
         if not allowed:
             logger.warning(