Check prometheus is online with simple query

pkg/metrics/providers/prometheus.go

@@ -15,6 +15,8 @@ import (
  flaggerv1 "github.com/weaveworks/flagger/pkg/apis/flagger/v1beta1"
 )
 
+const prometheusOnlineQuery = "vector(1)"
+
 // PrometheusProvider executes promQL queries
 type PrometheusProvider struct {
  timeout time.Duration
@@ -132,41 +134,15 @@ func (p *PrometheusProvider) RunQuery(query string) (float64, error) {
  return *value, nil
 }
 
-// IsOnline calls the Prometheus status endpoint and returns an error if the API is unreachable
+// IsOnline run simple Prometheus query and returns an error if the API is unreachable
 func (p *PrometheusProvider) IsOnline() (bool, error) {
- u, err := url.Parse("./api/v1/status/flags")
+ value, err := p.RunQuery(prometheusOnlineQuery)
  if err != nil {
- return false, fmt.Errorf("url.Parse failed: %w", err)
+ return false, fmt.Errorf("running query failed: %w", err)
  }
- u.Path = path.Join(p.url.Path, u.Path)
-
- u = p.url.ResolveReference(u)
 
- req, err := http.NewRequest("GET", u.String(), nil)
- if err != nil {
- return false, fmt.Errorf("http.NewRequest failed: %w", err)
- }
-
- if p.username != "" && p.password != "" {
- req.SetBasicAuth(p.username, p.password)
- }
-
- ctx, cancel := context.WithTimeout(req.Context(), p.timeout)
- defer cancel()
-
- r, err := http.DefaultClient.Do(req.WithContext(ctx))
- if err != nil {
- return false, fmt.Errorf("request failed: %w", err)
- }
- defer r.Body.Close()
-
- b, err := ioutil.ReadAll(r.Body)
- if err != nil {
- return false, fmt.Errorf("error reading body: %w", err)
- }
-
- if 400 <= r.StatusCode {
- return false, fmt.Errorf("error response: %s", string(b))
+ if value != float64(1) {
+ return false, fmt.Errorf("value is not 1 for query: %s", prometheusOnlineQuery)
  }
 
  return true, nil

pkg/metrics/providers/prometheus_test.go

@@ -147,22 +147,61 @@ func TestPrometheusProvider_RunQueryWithBasicAuth(t *testing.T) {
 }
 
 func TestPrometheusProvider_IsOnline(t *testing.T) {
- ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
- w.WriteHeader(http.StatusBadGateway)
- }))
- defer ts.Close()
+ t.Run("fail", func(t *testing.T) {
+ ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+ w.WriteHeader(http.StatusBadGateway)
+ }))
+ defer ts.Close()
 
- clients := prometheusFake()
+  clients := prometheusFake()
 
- template, err := clients.flaggerClient.FlaggerV1beta1().MetricTemplates("default").Get(context.TODO(), "prometheus", metav1.GetOptions{})
- require.NoError(t, err)
- template.Spec.Provider.Address = ts.URL
- template.Spec.Provider.SecretRef = nil
+  template, err := clients.flaggerClient.FlaggerV1beta1().MetricTemplates("default").Get(context.TODO(), "prometheus", metav1.GetOptions{})
+  require.NoError(t, err)
+  template.Spec.Provider.Address = ts.URL
+  template.Spec.Provider.SecretRef = nil
 
- prom, err := NewPrometheusProvider(template.Spec.Provider, nil)
- require.NoError(t, err)
+ prom, err := NewPrometheusProvider(template.Spec.Provider, nil)
+ require.NoError(t, err)
+
+ ok, err := prom.IsOnline()
+ assert.Error(t, err, "Got no error wanted %v", http.StatusBadGateway)
+ assert.False(t, ok)
+ })
+
+ t.Run("ok", func(t *testing.T) {
+ expected := `vector(1)`
+ ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+ promql := r.URL.Query()["query"][0]
+ assert.Equal(t, expected, promql)
+
+ if assert.Contains(t, r.Header, "Authorization") {
+
+ }
+ header, ok := r.Header["Authorization"]
+ if assert.True(t, ok, "Authorization header not found") {
+ assert.True(t, strings.Contains(header[0], "Basic"), "Basic authorization header not found")
+ }
+
+ json := `{"status":"success","data":{"resultType":"vector","result":[{"metric":{},"value":[1545905245.458,"1"]}]}}`
+ w.Write([]byte(json))
+ }))
+ defer ts.Close()
+
+ clients := prometheusFake()
 
- ok, err := prom.IsOnline()
- assert.Error(t, err, "Got no error wanted %v", http.StatusBadGateway)
- assert.False(t, ok)
+ template, err := clients.flaggerClient.FlaggerV1beta1().MetricTemplates("default").Get(context.TODO(), "prometheus", metav1.GetOptions{})
+ require.NoError(t, err)
+ template.Spec.Provider.Address = ts.URL
+
+ secret, err := clients.kubeClient.CoreV1().Secrets("default").Get(context.TODO(), "prometheus", metav1.GetOptions{})
+ require.NoError(t, err)
+
+ prom, err := NewPrometheusProvider(template.Spec.Provider, secret.Data)
+ require.NoError(t, err)
+
+ ok, err := prom.IsOnline()
+ require.NoError(t, err)
+
+ assert.Equal(t, true, ok)
+ })
 }