Ignored Nan and Infinite float values

internal/integration/emitter.go

@@ -4,6 +4,7 @@
 package integration
 
 import (
+	"context"
 	"crypto/tls"
 	"encoding/json"
 	"fmt"
@@ -30,10 +31,16 @@ type Emitter interface {
 	Emit([]Metric) error
 }
 
+// Harvester aggregates and reports metrics and spans
+type harvester interface {
+	RecordMetric(m telemetry.Metric)
+	HarvestNow(ct context.Context)
+}
+
 // TelemetryEmitter emits metrics using the go-telemetry-sdk.
 type TelemetryEmitter struct {
 	name            string
-	harvester       *telemetry.Harvester
+	harvester       harvester
 	deltaCalculator *cumulative.DeltaCalculator
 }
 
@@ -161,14 +168,19 @@ func NewTelemetryEmitter(cfg TelemetryEmitterConfig) (*TelemetryEmitter, error)
 		deltaExpirationCheckInterval,
 	)
 
-	harvester, err := telemetry.NewHarvester(cfg.HarvesterOpts...)
+	var h harvester
+	h, err := telemetry.NewHarvester(cfg.HarvesterOpts...)
 	if err != nil {
 		return nil, errors.Wrap(err, "could not create new Harvester")
 	}
 
+	// Wrap the harvester so we can filter out invalid float values: NaN and Infinity.
+	// If we do send them, the harvester will always output these as errors
+	h = harvesterDecorator{h}
+
 	return &TelemetryEmitter{
 		name:            "telemetry",
-		harvester:       harvester,
+		harvester:       h,
 		deltaCalculator: dc,
 	}, nil
 }
@@ -187,6 +199,7 @@ func (te *TelemetryEmitter) Emit(metrics []Metric) error {
 	// the measurement that already took place.
 	now := time.Now()
 	for _, metric := range metrics {
+
 		switch metric.metricType {
 		case metricType_GAUGE:
 			te.harvester.RecordMetric(telemetry.Gauge{

internal/integration/emitter_test.go

@@ -179,6 +179,12 @@ func TestTelemetryEmitterEmit(t *testing.T) {
 			value:      summary,
 			attributes: labels.Set{},
 		},
+		{
+			name:       "not a number, NAN",
+			metricType: metricType_COUNTER,
+			value:      math.NaN(),
+			attributes: labels.Set{},
+		},
 	}
 
 	var rawMetrics []interface{}

internal/integration/harvester_decorator.go

@@ -0,0 +1,46 @@
+package integration
+
+import (
+	"context"
+	"math"
+
+	"github.com/newrelic/newrelic-telemetry-sdk-go/telemetry"
+	"github.com/sirupsen/logrus"
+)
+
+// harvesterDecorator is a layer on top of another harvester that filters out NaN and Infinite float values.
+type harvesterDecorator struct {
+	innerHarvester harvester
+}
+
+func (ha harvesterDecorator) RecordMetric(m telemetry.Metric) {
+	switch a := m.(type) {
+	case telemetry.Count:
+		ha.processMetric(a.Value, m)
+	case telemetry.Summary:
+		ha.processMetric(a.Sum, m)
+	case telemetry.Gauge:
+		ha.processMetric(a.Value, m)
+	default:
+		logrus.Debugf("Unexpected metric in harvesterDecorator: #%v", m)
+		ha.innerHarvester.RecordMetric(m)
+	}
+}
+
+func (ha harvesterDecorator) HarvestNow(ctx context.Context) {
+	ha.innerHarvester.HarvestNow(ctx)
+}
+
+func (ha harvesterDecorator) processMetric(f float64, m telemetry.Metric) {
+	if math.IsNaN(f) {
+		logrus.Debugf("Ignoring NaN float value for metric: %v", m)
+		return
+	}
+
+	if math.IsInf(f, 0) {
+		logrus.Debugf("Ignoring Infinite float value for metric: %v", m)
+		return
+	}
+
+	ha.innerHarvester.RecordMetric(m)
+}