*: add json tag to RunnerMetricReport

* Do not show key/value if value is empty
* Add BuildPercentileLatencies back into metrics pkg
* Render time.Duration into string

Signed-off-by: Wei Fu <weifu@microsoft.com>

api/types/metric.go

@@ -1,7 +1,5 @@
 package types
 
-import "time"
-
 // ResponseStats is the report about benchmark result.
 type ResponseStats struct {
 	// List of failures
@@ -14,15 +12,15 @@ type ResponseStats struct {
 
 type RunnerMetricReport struct {
 	// Total represents total number of requests.
-	Total int
+	Total int `json:"total"`
 	// List of failures
-	FailureList []error
+	FailureList []error `json:"failureList,omitempty"`
 	// Duration means the time of benchmark.
-	Duration time.Duration
+	Duration string `json:"duration"`
 	// All the observed latencies
-	Latencies []float64
+	Latencies []float64 `json:"latencies,omitempty"`
 	// total bytes read from apiserver
-	TotalReceivedBytes int64
+	TotalReceivedBytes int64 `json:"totalReceivedBytes"`
 	// PercentileLatencies represents the latency distribution in seconds.
-	PercentileLatencies [][2]float64 // [2]float64{percentile, value}
+	PercentileLatencies [][2]float64 `json:"percentileLatencies,omitempty"`
 }

cmd/kperf/commands/runner/runner.go

@@ -11,6 +11,7 @@ import (
 	"strconv"
 
 	"github.com/Azure/kperf/api/types"
+	"github.com/Azure/kperf/metrics"
 	"github.com/Azure/kperf/request"
 
 	"github.com/urfave/cli"
@@ -183,13 +184,15 @@ func loadConfig(cliCtx *cli.Context) (*types.LoadProfile, error) {
 	return &profileCfg, nil
 }
 
+// printResponseStats prints types.RunnerMetricReport into underlying file.
 func printResponseStats(f *os.File, rawDataFlagIncluded bool, stats *request.Result) error {
 	output := types.RunnerMetricReport{
-		Total:              stats.Total,
-		FailureList:        stats.FailureList,
-		Duration:           stats.Duration,
-		Latencies:          stats.Latencies,
-		TotalReceivedBytes: stats.TotalReceivedBytes,
+		Total:               stats.Total,
+		FailureList:         stats.FailureList,
+		Duration:            stats.Duration.String(),
+		Latencies:           stats.Latencies,
+		TotalReceivedBytes:  stats.TotalReceivedBytes,
+		PercentileLatencies: metrics.BuildPercentileLatencies(stats.Latencies),
 	}
 
 	encoder := json.NewEncoder(f)
@@ -203,7 +206,5 @@ func printResponseStats(f *os.File, rawDataFlagIncluded bool, stats *request.Res
 	if err != nil {
 		return fmt.Errorf("failed to encode json: %w", err)
 	}
-
 	return nil
-
 }

metrics/utils.go

@@ -0,0 +1,28 @@
+package metrics
+
+import (
+	"math"
+	"sort"
+)
+
+// BuildPercentileLatencies builds percentile latencies.
+func BuildPercentileLatencies(latencies []float64) [][2]float64 {
+	if len(latencies) == 0 {
+		return nil
+	}
+
+	var percentiles = []float64{0, 0.5, 0.90, 0.95, 0.99, 1}
+
+	res := make([][2]float64, len(percentiles))
+
+	n := len(latencies)
+	sort.Float64s(latencies)
+	for pi, pv := range percentiles {
+		idx := int(math.Ceil(float64(n) * pv))
+		if idx > 0 {
+			idx--
+		}
+		res[pi] = [2]float64{pv, latencies[idx]}
+	}
+	return res
+}

metrics/utils_test.go

@@ -0,0 +1,33 @@
+package metrics
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestBuildPercentileLatencies(t *testing.T) {
+	ls := make([]float64, 100)
+	ls[0] = 50
+	ls[1] = 49
+	ls[2] = 1
+	res := BuildPercentileLatencies(ls)
+	assert.Equal(t, [2]float64{0, 0}, res[0])
+	assert.Equal(t, [2]float64{0.5, 0}, res[1])
+	assert.Equal(t, [2]float64{0.9, 0}, res[2])
+	assert.Equal(t, [2]float64{0.95, 0}, res[3])
+	assert.Equal(t, [2]float64{0.99, 49}, res[4])
+	assert.Equal(t, [2]float64{1, 50}, res[5])
+
+	ls = make([]float64, 1000)
+	ls[0] = 50
+	ls[1] = 49
+	ls[2] = -1
+	res = BuildPercentileLatencies(ls)
+	assert.Equal(t, [2]float64{0, -1}, res[0])
+	assert.Equal(t, [2]float64{0.5, 0}, res[1])
+	assert.Equal(t, [2]float64{0.9, 0}, res[2])
+	assert.Equal(t, [2]float64{0.95, 0}, res[3])
+	assert.Equal(t, [2]float64{0.99, 0}, res[4])
+	assert.Equal(t, [2]float64{1, 50}, res[5])
+}