Add support to specify metric name for stress

This adds feature to stress command to get the metric name from the
user and does the stress on only these metrics, if metric name is not
specified then it goes back to old behaviour of fetching all the metric
name from thanos store

Co-authored-by: Raghav Gupta <[email protected]>

cmd/thanosbench/stress.go

@@ -26,11 +26,34 @@ var (
 	maxTime = timestamp.FromTime(time.Unix(math.MaxInt64/1000-62135596801, 999999999))
 )
 
+func getMetricsFromStore(ctx context.Context, timeout *time.Duration, c storepb.StoreClient) ([]string, error) {
+	lblvlsCtx, lblvlsCancel := context.WithTimeout(ctx, *timeout)
+	defer lblvlsCancel()
+
+	labelvaluesResp, err := c.LabelValues(lblvlsCtx, &storepb.LabelValuesRequest{
+		Label: labels.MetricName,
+		Start: minTime,
+		End:   maxTime,
+	})
+	if err != nil {
+		return nil, err
+	}
+	if len(labelvaluesResp.Warnings) > 0 {
+		return nil, errors.New(fmt.Sprintf("got %#v warnings from LabelValues() call", labelvaluesResp.Warnings))
+	}
+	labelvalues := labelvaluesResp.Values
+	if len(labelvalues) == 0 {
+		return nil, errors.New("the StoreAPI responded with zero metric names")
+	}
+	return labelvalues, nil
+}
+
 func registerStress(m map[string]setupFunc, app *kingpin.Application) {
 	cmd := app.Command("stress", "Stress tests a remote StoreAPI.")
 	workers := cmd.Flag("workers", "Number of go routines for stress testing.").Required().Int()
 	timeout := cmd.Flag("timeout", "Timeout of each operation").Default("60s").Duration()
 	lookback := cmd.Flag("query.look-back", "How much time into the past at max we should look back").Default("300h").Duration()
+	userSpecifiedMetrics := cmd.Flag("metric-name", "Metric to query for").Strings()
 	target := cmd.Arg("target", "IP:PORT pair of the target to stress.").Required().TCP()
 
 	// TODO(GiedriusS): send other requests like Info() as well.
@@ -43,28 +66,19 @@ func registerStress(m map[string]setupFunc, app *kingpin.Application) {
 				return err
 			}
 			defer conn.Close()
-			c := storepb.NewStoreClient(conn)
 
-			lblvlsCtx, lblvlsCancel := context.WithTimeout(mainCtx, *timeout)
-			defer lblvlsCancel()
+			c := storepb.NewStoreClient(conn)
+			errg, errCtx := errgroup.WithContext(mainCtx)
 
-			labelvaluesResp, err := c.LabelValues(lblvlsCtx, &storepb.LabelValuesRequest{
-				Label: labels.MetricName,
-				Start: minTime,
-				End:   maxTime,
-			})
-			if err != nil {
-				return err
-			}
-			if len(labelvaluesResp.Warnings) > 0 {
-				return errors.New(fmt.Sprintf("got %#v warnings from LabelValues() call", labelvaluesResp.Warnings))
+			var metrics []string
+			if *userSpecifiedMetrics != nil && len(*userSpecifiedMetrics) != 0 {
+				metrics = *userSpecifiedMetrics
+			} else {
+				metrics, err = getMetricsFromStore(mainCtx, timeout, c)
+				if err != nil {
+					return err
+				}
 			}
-			labelvalues := labelvaluesResp.Values
-			if len(labelvalues) == 0 {
-				return errors.New("the StoreAPI responded with zero metric names")
-			}
-
-			errg, errCtx := errgroup.WithContext(mainCtx)
 
 			for i := 0; i < *workers; i++ {
 				errg.Go(func() error {
@@ -78,7 +92,7 @@ func registerStress(m map[string]setupFunc, app *kingpin.Application) {
 						opCtx, cancel := context.WithTimeout(errCtx, *timeout)
 						defer cancel()
 
-						randomMetric := labelvalues[rand.Intn(len(labelvalues))]
+						randomMetric := metrics[rand.Intn(len(metrics))]
 						max := time.Now().Unix()
 						min := time.Now().Unix() - rand.Int63n(int64(lookback.Seconds()))