Add random histogram to telemetrygen

cmd/telemetrygen/internal/metrics/metrics_types.go

@@ -10,8 +10,9 @@ import (
 type metricType string
 
 const (
-	metricTypeGauge = "Gauge"
-	metricTypeSum   = "Sum"
+	metricTypeGauge     = "Gauge"
+	metricTypeSum       = "Sum"
+	metricTypeHistogram = "Histogram"
 )
 
 // String is used both by fmt.Print and by Cobra in help text
@@ -22,11 +23,11 @@ func (e *metricType) String() string {
 // Set must have pointer receiver so it doesn't change the value of a copy
 func (e *metricType) Set(v string) error {
 	switch v {
-	case "Gauge", "Sum":
+	case "Gauge", "Sum", "Histogram":
 		*e = metricType(v)
 		return nil
 	default:
-		return errors.New(`must be one of "Gauge" or "Sum"`)
+		return errors.New(`must be one of "Gauge", "Sum", "Histogram"`)
 	}
 }
 

cmd/telemetrygen/internal/metrics/worker.go

@@ -5,6 +5,7 @@ package metrics
 
 import (
 	"context"
+	rand "math/rand/v2"
 	"sync"
 	"sync/atomic"
 	"time"
@@ -38,6 +39,8 @@ func (w worker) simulateMetrics(res *resource.Resource, exporterFunc func() (sdk
 		w.logger.Error("failed to create the exporter", zap.Error(err))
 		return
 	}
+	randomPCG := rand.NewPCG(0, 0)
+	randomgenerator := rand.New(randomPCG)
 
 	defer func() {
 		w.logger.Info("stopping the exporter")
@@ -82,6 +85,23 @@ func (w worker) simulateMetrics(res *resource.Resource, exporterFunc func() (sdk
 					},
 				},
 			})
+		case metricTypeHistogram:
+			metrics = append(metrics, metricdata.Metrics{
+				Name: w.metricName,
+				Data: metricdata.Histogram[int64]{
+					Temporality: metricdata.DeltaTemporality,
+					DataPoints: []metricdata.HistogramDataPoint[int64]{
+						{
+							StartTime:  time.Now().Add(-1 * time.Second),
+							Time:       time.Now(),
+							Attributes: attribute.NewSet(signalAttrs...),
+							Exemplars:  w.exemplars,
+							Count:      uint64(randomgenerator.Int64N(10)),
+							Sum:        randomgenerator.Int64N(10),
+						},
+					},
+				},
+			})
 		default:
 			w.logger.Fatal("unknown metric type")
 		}