test: fix testPrometheusUTF8LabelSupport for Prometheus V2

Assisted-By: Cursor
Signed-off-by: Jayapriya Pai <slashpai9@gmail.com>

test/e2e/prometheus_test.go

@@ -32,6 +32,7 @@ import (
 	"testing"
 	"time"
 
+	"github.com/blang/semver/v4"
 	"github.com/kylelemons/godebug/pretty"
 	"github.com/stretchr/testify/require"
 	"golang.org/x/net/http2"
@@ -5788,6 +5789,39 @@ func testPrometheusUTF8LabelSupport(t *testing.T) {
 	_, err = framework.KubeClient.CoreV1().Services(ns).Create(context.Background(), service, metav1.CreateOptions{})
 	require.NoError(t, err)
 
+	// Determine the Prometheus version that will be used.
+	promVersion := operator.DefaultPrometheusVersion
+	if os.Getenv("TEST_PROMETHEUS_V2") == "true" {
+		promVersion = operator.DefaultPrometheusV2
+	}
+
+	// Parse the version to check if it supports UTF-8.
+	parsedVersion, err := semver.ParseTolerant(promVersion)
+	require.NoError(t, err)
+
+	supportsUTF8 := parsedVersion.GTE(semver.MustParse("3.0.0"))
+
+	var relabelConfigs []monitoringv1.RelabelConfig
+	var expectedLabelName string
+
+	if supportsUTF8 {
+		// Use UTF-8 label for Prometheus 3.0+
+		relabelConfigs = []monitoringv1.RelabelConfig{{
+			SourceLabels: []monitoringv1.LabelName{"__meta_kubernetes_service_label_cluster"},
+			TargetLabel:  "service_clustér_label",
+			Action:       "replace",
+		}}
+		expectedLabelName = "service_clustér_label"
+	} else {
+		// Use ASCII-only label for Prometheus 2.x
+		relabelConfigs = []monitoringv1.RelabelConfig{{
+			SourceLabels: []monitoringv1.LabelName{"__meta_kubernetes_service_label_cluster"},
+			TargetLabel:  "service_cluster_label",
+			Action:       "replace",
+		}}
+		expectedLabelName = "service_cluster_label"
+	}
+
 	sm := &monitoringv1.ServiceMonitor{
 		ObjectMeta: metav1.ObjectMeta{
 			Name:      "utf8-servicemonitor",
@@ -5799,13 +5833,9 @@ func testPrometheusUTF8LabelSupport(t *testing.T) {
 				MatchLabels: map[string]string{"app.name": "instrumented-sample-app"},
 			},
 			Endpoints: []monitoringv1.Endpoint{{
-				Port:     "web",
+				Port:           "web",
-				Interval: "2s",
+				Interval:       "2s",
-				RelabelConfigs: []monitoringv1.RelabelConfig{{
+				RelabelConfigs: relabelConfigs,
-					SourceLabels: []monitoringv1.LabelName{"__meta_kubernetes_service_label_cluster"},
-					TargetLabel:  "service_clustér_label",
-					Action:       "replace",
-				}},
 				BasicAuth: &monitoringv1.BasicAuth{
 					Username: v1.SecretKeySelector{
 						LocalObjectReference: v1.LocalObjectReference{Name: "basic-auth"},
@@ -5847,26 +5877,32 @@ func testPrometheusUTF8LabelSupport(t *testing.T) {
 	// Default Prometheus service name is "prometheus-operated".
 	promSvcName := "prometheus-operated"
 
-	// Wait for the instrumented-sample-app target to be discovered
+	// Wait for the instrumented-sample-app target to be discovered.
 	err = framework.WaitForHealthyTargets(context.Background(), ns, promSvcName, 1)
 	require.NoError(t, err)
 
-	// Verify UTF8 labels work in queries.
+	// Verify label queries work based on the Prometheus version.
+	queryLabel := fmt.Sprintf(`{"%s"="dev"}`, expectedLabelName)
 	err = wait.PollUntilContextTimeout(context.Background(), 5*time.Second, 2*time.Minute, false, func(ctx context.Context) (bool, error) {
-		results, err := framework.PrometheusQuery(ns, promSvcName, "http", `{"service_clustér_label"="dev"}`)
+		results, err := framework.PrometheusQuery(ns, promSvcName, "http", queryLabel)
 		if err != nil {
-			t.Logf("UTF8 label query failed: %v", err)
+			t.Logf("Label query failed: %v", err)
 			return false, nil
 		}
 
 		if len(results) == 0 {
-			t.Logf("UTF8 label query returned no results")
+			t.Logf("Label query returned no results")
 			return false, nil
 		}
 
 		return true, nil
 	})
-	require.NoError(t, err, "UTF-8 label queries should work in Prometheus 3.0+ queries")
+
+	if supportsUTF8 {
+		require.NoError(t, err, "UTF-8 label queries should work in Prometheus 3.0+")
+	} else {
+		require.NoError(t, err, "ASCII label queries should work in Prometheus 2.x")
+	}
 }
 
 func isAlertmanagerDiscoveryWorking(ns, promSVCName, alertmanagerName string) func(ctx context.Context) (bool, error) {