[Feat][Router]: Add automatic retry with exponential backoff and jitter

src/tests/test_audio_speech_routing.py

@@ -14,6 +14,7 @@
 from vllm_router.routers.routing_logic import (
     RoundRobinRouter,
 )
+from vllm_router.services.request_service.retry import RetryConfig
 from vllm_router.utils import SingletonABCMeta
 
 
@@ -48,7 +49,6 @@ def cleanup_singletons():
 def setup():
     """Yield a (request, router) pair with all app-state dependencies patched."""
     router = RoundRobinRouter()
-    router.max_instance_failover_reroute_attempts = 0
 
     sd = MagicMock()
     sd.get_endpoint_info.return_value = ENDPOINTS
@@ -63,6 +63,7 @@ def setup():
     state.semantic_cache_available = False
     state.callbacks = None
     state.external_provider_registry = None
+    state.retry_config = RetryConfig(max_attempts=1)
 
     req = MagicMock()
     req.headers = {"content-type": "application/json"}

src/tests/test_multipart_proxy.py

@@ -78,7 +78,6 @@ async def router_client(backend_url, model=AUDIO_MODEL):
 
         router = initialize_routing_logic(
             RoutingLogic.ROUND_ROBIN,
-            max_instance_failover_reroute_attempts=0,
         )
         stack.callback(cleanup_routing_logic)