e2e: add cmd probe failover test with true/false command nodes

tests/e2e/probe_test.go

@@ -85,6 +85,21 @@ func (s *ProbeSuite) TestLowestLatencyProbe() {
 	}
 }
 
+// TestCmdProbeFailover verifies that the cmd probe detects a dead node via
+// shell exit code and marks it before real traffic, so FailFilter excludes it.
+func (s *ProbeSuite) TestCmdProbeFailover() {
+	gostC, err := RunGostContainerWithPorts(s.ctx, SharedNetworkName, "testdata/probe/cmd.yaml", "8080/tcp")
+	s.Require().NoError(err)
+	defer gostC.Terminate(s.ctx)
+
+	// The probe fires at startup; the dead node is already marked.
+	for range 10 {
+		code, body := s.proxyRequest(gostC, "8080")
+		s.Require().Equal(0, code, "all requests must succeed; dead cmd node pre-marked")
+		s.Require().Contains(body, "hello-gost")
+	}
+}
+
 func TestProbeSuite(t *testing.T) {
 	suite.Run(t, new(ProbeSuite))
 }

tests/e2e/testdata/probe/cmd.yaml

@@ -0,0 +1,43 @@
+services:
+- name: proxy
+  addr: :8080
+  handler:
+    type: http
+    chain: my-chain
+  listener:
+    type: tcp
+
+# Live relay: forwards to the echo server.
+- name: relay
+  addr: 127.0.0.1:18081
+  handler:
+    type: http
+  listener:
+    type: tcp
+
+chains:
+- name: my-chain
+  hops:
+  - name: hop-1
+    selector:
+      strategy: round
+      maxFails: 1
+      failTimeout: 10s
+    nodes:
+    - name: node-live
+      addr: 127.0.0.1:18081
+      connector:
+        type: http
+      probe:
+        type: cmd
+        command: "true"
+        interval: 5s
+    # This node's probe always fails → pre-marked dead → FailFilter excludes it.
+    - name: node-dead
+      addr: 127.0.0.1:18082
+      connector:
+        type: http
+      probe:
+        type: cmd
+        command: "false"
+        interval: 5s