Adding simple retry for empty value

We are seeing `NaN` in some CI runs. This is due to no output from
netperf. This change makes a second attempt in the event the parsing
fails to succeed.

Signed-off-by: Joe Talerico <rook@redhat.com>

cmd/k8s-netperf/k8s-netperf.go

@@ -385,7 +385,13 @@ func executeWorkload(nc config.Config, s config.PerfScenarios, hostNet bool, ipe
 			nr, err = netperf.ParseResults(&r)
 			if err != nil {
 				log.Error(err)
-				os.Exit(1)
+				log.Info("Rerunning test due to NaN")
+				r, err := netperf.Run(s.ClientSet, s.RestConfig, nc, Client, serverIP)
+				nr, err = netperf.ParseResults(&r)
+				if err != nil {
+					log.Error(err)
+					os.Exit(1)
+				}
 			}
 		}
 		npr.LossSummary = append(npr.LossSummary, float64(nr.LossPercent))

pkg/netperf/netperf.go

@@ -4,6 +4,7 @@ import (
 	"bytes"
 	"context"
 	"fmt"
+	"math"
 	"strconv"
 	"strings"
 
@@ -114,6 +115,9 @@ func ParseResults(stdout *bytes.Buffer) (sample.Sample, error) {
 			sample.Retransmits, _ = strconv.ParseFloat(strings.Trim(l[1], "\r"), 64)
 		}
 	}
+	if math.IsNaN(sample.Throughput) {
+		return sample, fmt.Errorf("Throughput value is NaN")
+	}
 	sample.LossPercent = 100 - (recv / send * 100)
 	return sample, nil
 }