Convert NaN or Infinity value metrics to string (#271)

* Convert NaN or Infinity value metrics to string

* Fixed test name

Author: heidmotron

events/events.go

@@ -3,6 +3,7 @@ package events
 import (
 	"encoding/json"
 	"fmt"
+	"math"
 	"sort"
 	"strings"
 
@@ -121,11 +122,21 @@ func LogMessage(msg *events.Envelope) *Event {
 
 func ValueMetric(msg *events.Envelope) *Event {
 	valMetric := msg.GetValueMetric()
+	value := valMetric.GetValue()
 
 	fields := logrus.Fields{
 		"name":  valMetric.GetName(),
 		"unit":  valMetric.GetUnit(),
-		"value": valMetric.GetValue(),
+		"value": value,
+	}
+
+	// Convert special values
+	if math.IsNaN(value) {
+		fields["value"] = "NaN"
+	} else if math.IsInf(value, 1) {
+		fields["value"] = "Infinity"
+	} else if math.IsInf(value, -1) {
+		fields["value"] = "-Infinity"
 	}
 
 	return &Event{

events/events_test.go

@@ -1,6 +1,8 @@
 package events_test
 
 import (
+	"math"
+
 	fevents "github.com/cloudfoundry-community/splunk-firehose-nozzle/events"
 	"github.com/cloudfoundry-community/splunk-firehose-nozzle/testing"
 	. "github.com/cloudfoundry/sonde-go/events"
@@ -88,6 +90,45 @@ var _ = Describe("Events", func() {
 		Expect(evt.Fields["unit"]).To(Equal(unit))
 	})
 
+	It("ValueMetric NaN", func() {
+		msg = NewValueMetric()
+		nan := math.NaN()
+		msg.ValueMetric.Value = &nan
+		evt := fevents.ValueMetric(msg)
+		Expect(evt).ToNot(BeNil())
+		Expect(evt.Fields).ToNot(BeNil())
+		Expect(evt.Msg).To(Equal(""))
+		Expect(evt.Fields["name"]).To(Equal(name))
+		Expect(evt.Fields["value"]).To(Equal("NaN"))
+		Expect(evt.Fields["unit"]).To(Equal(unit))
+	})
+
+	It("ValueMetric +Infinity", func() {
+		msg = NewValueMetric()
+		inf := math.Inf(1)
+		msg.ValueMetric.Value = &inf
+		evt := fevents.ValueMetric(msg)
+		Expect(evt).ToNot(BeNil())
+		Expect(evt.Fields).ToNot(BeNil())
+		Expect(evt.Msg).To(Equal(""))
+		Expect(evt.Fields["name"]).To(Equal(name))
+		Expect(evt.Fields["value"]).To(Equal("Infinity"))
+		Expect(evt.Fields["unit"]).To(Equal(unit))
+	})
+
+	It("ValueMetric -Infinity", func() {
+		msg = NewValueMetric()
+		inf := math.Inf(-1)
+		msg.ValueMetric.Value = &inf
+		evt := fevents.ValueMetric(msg)
+		Expect(evt).ToNot(BeNil())
+		Expect(evt.Fields).ToNot(BeNil())
+		Expect(evt.Msg).To(Equal(""))
+		Expect(evt.Fields["name"]).To(Equal(name))
+		Expect(evt.Fields["value"]).To(Equal("-Infinity"))
+		Expect(evt.Fields["unit"]).To(Equal(unit))
+	})
+
 	It("CounterEvent", func() {
 		msg = NewCounterEvent()
 		evt := fevents.CounterEvent(msg)