Hand a finished runner's pod back as soon as its job is over (#4673)

charts/gha-runner-scale-set-controller/tests/template_test.go

@@ -866,6 +866,55 @@ func TestTemplate_ControllerDeployment_MaxConcurrentReconciles(t *testing.T) {
 	})
 }
 
+// TestTemplate_ControllerDeployment_TerminatedRunnerPodGracePeriod pins how the
+// grace period of a finished runner pod reaches the controller.
+//
+// Leaving the value unset has to render no flag at all, so the controller keeps
+// its own default of removing those pods immediately. Setting it is what a
+// cluster that wants finished pods to stay readable for a while does, and a
+// negative value is how it asks for the pod's own grace period instead.
+func TestTemplate_ControllerDeployment_TerminatedRunnerPodGracePeriod(t *testing.T) {
+	t.Parallel()
+
+	helmChartPath, err := filepath.Abs("../../gha-runner-scale-set-controller")
+	require.NoError(t, err)
+
+	releaseName := "test-arc"
+	namespaceName := "test-" + strings.ToLower(random.UniqueID())
+
+	renderArgs := func(t *testing.T, values map[string]string) []string {
+		options := &helm.Options{
+			Logger:         logger.Discard,
+			SetValues:      values,
+			KubectlOptions: k8s.NewKubectlOptions("", "", namespaceName),
+		}
+
+		output := helm.RenderTemplateContext(t, t.Context(), options, helmChartPath, releaseName, []string{"templates/deployment.yaml"})
+
+		var deployment appsv1.Deployment
+		helm.UnmarshalK8SYaml(t, output, &deployment)
+
+		require.Len(t, deployment.Spec.Template.Spec.Containers, 1)
+		return deployment.Spec.Template.Spec.Containers[0].Args
+	}
+
+	t.Run("no flag renders by default", func(t *testing.T) {
+		for _, arg := range renderArgs(t, nil) {
+			assert.NotContains(t, arg, "--terminated-runner-pod-grace-period-seconds")
+		}
+	})
+
+	t.Run("the flag renders when configured", func(t *testing.T) {
+		args := renderArgs(t, map[string]string{"flags.terminatedRunnerPodGracePeriodSeconds": "30"})
+		assert.Contains(t, args, "--terminated-runner-pod-grace-period-seconds=30")
+	})
+
+	t.Run("the flag renders when it hands the grace period back to the pod", func(t *testing.T) {
+		args := renderArgs(t, map[string]string{"flags.terminatedRunnerPodGracePeriodSeconds": "-1"})
+		assert.Contains(t, args, "--terminated-runner-pod-grace-period-seconds=-1")
+	})
+}
+
 func TestTemplate_ControllerContainerEnvironmentVariables(t *testing.T) {
 	t.Parallel()