tests/e2e: Add e2e test to make sure all deprecated metrics are being

dropped

tests/e2e/main_test.go

@@ -17,6 +17,7 @@ package e2e
 import (
 	"log"
 	"os"
+	"strings"
 	"testing"
 	"time"
 
@@ -57,7 +58,6 @@ func testMain(m *testing.M) int {
 }
 
 func TestQueryPrometheus(t *testing.T) {
-	t.Parallel()
 	queries := []struct {
 		query   string
 		expectN int
@@ -72,8 +72,8 @@ func TestQueryPrometheus(t *testing.T) {
 			query:   `up{job="apiserver"} == 1`,
 			expectN: 1,
 		}, {
-		 	query:   `up{job="kube-state-metrics"} == 1`,
-		 	expectN: 1,
+			query:   `up{job="kube-state-metrics"} == 1`,
+			expectN: 1,
 		}, {
 			query:   `up{job="prometheus-k8s"} == 1`,
 			expectN: 1,
@@ -116,3 +116,25 @@ func TestQueryPrometheus(t *testing.T) {
 		t.Fatal(err)
 	}
 }
+
+func TestDroppedMetrics(t *testing.T) {
+	// query metadata for all metrics and their metadata
+	md, err := promClient.metadata("{job=~\".+\"}")
+	if err != nil {
+		log.Fatal(err)
+	}
+	for _, k := range md.Data {
+		// check if the metric' help text contains Deprecated
+		if strings.Contains(k.Help, "Deprecated") {
+			// query prometheus for the Deprecated metric
+			n, err := promClient.query(k.Metric)
+			if err != nil {
+				log.Fatal(err)
+			}
+			if n > 0 {
+				t.Fatalf("deprecated metric with name: %s and help text: %s exists.", k.Metric, k.Help)
+			}
+		}
+
+	}
+}

tests/e2e/prometheus_client.go

@@ -15,6 +15,10 @@
 package e2e
 
 import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+
 	"k8s.io/client-go/kubernetes"
 
 	"github.com/Jeffail/gabs"
@@ -50,3 +54,41 @@ func (c *prometheusClient) query(query string) (int, error) {
 	n, err := res.ArrayCountP("data.result")
 	return n, err
 }
+
+type Metadata struct {
+	Status string `json:"status,omitempty"`
+	Data   []Data `json:"data,omitempty"`
+}
+
+type Data struct {
+	Metric string `json:"metric,omitempty"`
+	Help   string `json:"help,omitempty"`
+}
+
+// metadata makes a request against the Prometheus /api/v1/targets/metadata endpoint.
+// It returns all the metrics and its metadata.
+func (c *prometheusClient) metadata(query string) (Metadata, error) {
+	req := c.kubeClient.CoreV1().RESTClient().Get().
+		Namespace("monitoring").
+		Resource("pods").
+		SubResource("proxy").
+		Name("prometheus-k8s-0:9090").
+		Suffix("/api/v1/targets/metadata").Param("match_target", query)
+
+	var data Metadata
+	b, err := req.DoRaw()
+	if err != nil {
+		return data, err
+	}
+
+	r := bytes.NewReader(b)
+	decoder := json.NewDecoder(r)
+	err = decoder.Decode(&data)
+	if err != nil {
+		return data, err
+	}
+	if data.Status != "success" {
+		return data, fmt.Errorf("status of returned response was not successful; status: %s", data.Status)
+	}
+	return data, err
+}