chore: import upstream snapshot with attribution

python/ray/serve/tests/test_failure_2.py

@@ -0,0 +1,61 @@
+import sys
+
+import httpx
+import pytest
+
+import ray
+from ray import serve
+from ray._common.test_utils import SignalActor
+
+
+def test_no_available_replicas_does_not_block_proxy(serve_instance):
+    """Test that handle blocking waiting for replicas doesn't block proxy.
+
+    This is essential so that other requests and health checks can pass while a
+    deployment is deploying/updating.
+
+    See https://github.com/ray-project/ray/issues/36460.
+    """
+
+    @serve.deployment
+    class SlowStarter:
+        def __init__(self, starting_actor, finish_starting_actor):
+            ray.get(starting_actor.send.remote())
+            ray.get(finish_starting_actor.wait.remote())
+
+        def __call__(self):
+            return "hi"
+
+    @ray.remote
+    def make_blocked_request():
+        r = httpx.get("http://localhost:8000/")
+        r.raise_for_status()
+        return r.text
+
+    # Loop twice: first iteration tests deploying from nothing, second iteration
+    # tests updating the replicas of an existing deployment.
+    for _ in range(2):
+        starting_actor = SignalActor.remote()
+        finish_starting_actor = SignalActor.remote()
+        serve._run(
+            SlowStarter.bind(starting_actor, finish_starting_actor), _blocking=False
+        )
+
+        # Ensure that the replica has been started (we use _blocking=False).
+        ray.get(starting_actor.wait.remote())
+
+        # The request shouldn't complete until the replica has finished started.
+        blocked_ref = make_blocked_request.remote()
+        with pytest.raises(TimeoutError):
+            ray.get(blocked_ref, timeout=1)
+        # If the proxy's loop was blocked, these would hang.
+        httpx.get("http://localhost:8000/-/routes").raise_for_status()
+        httpx.get("http://localhost:8000/-/healthz").raise_for_status()
+
+        # Signal the replica to finish starting; request should complete.
+        ray.get(finish_starting_actor.send.remote())
+        assert ray.get(blocked_ref) == "hi"
+
+
+if __name__ == "__main__":
+    sys.exit(pytest.main(["-v", "-s", __file__]))