From b5710a6a2128405f424b0f6670260b2e662fefc3 Mon Sep 17 00:00:00 2001
From: Daniel Nelson <daniel.nelson@influxdb.com>
Date: Mon, 5 Aug 2019 14:50:29 -0700
Subject: [PATCH] Skip floats that are NaN or Inf in Datadog output. (#6198)

---
 plugins/outputs/datadog/datadog.go      | 17 ++++++---
 plugins/outputs/datadog/datadog_test.go | 46 +++++++++++++++++++++++--
 2 files changed, 57 insertions(+), 6 deletions(-)

diff --git a/plugins/outputs/datadog/datadog.go b/plugins/outputs/datadog/datadog.go
index 62e73f115..736570726 100644
--- a/plugins/outputs/datadog/datadog.go
+++ b/plugins/outputs/datadog/datadog.go
@@ -5,6 +5,7 @@ import (
 	"encoding/json"
 	"fmt"
 	"log"
+	"math"
 	"net/http"
 	"net/url"
 	"strings"
@@ -63,9 +64,6 @@ func (d *Datadog) Connect() error {
 }
 
 func (d *Datadog) Write(metrics []telegraf.Metric) error {
-	if len(metrics) == 0 {
-		return nil
-	}
 	ts := TimeSeries{}
 	tempSeries := []*Metric{}
 	metricCounter := 0
@@ -75,6 +73,10 @@ func (d *Datadog) Write(metrics []telegraf.Metric) error {
 			metricTags := buildTags(m.TagList())
 			host, _ := m.GetTag("host")
 
+			if len(dogMs) == 0 {
+				continue
+			}
+
 			for fieldName, dogM := range dogMs {
 				// name of the datadog measurement
 				var dname string
@@ -98,6 +100,10 @@ func (d *Datadog) Write(metrics []telegraf.Metric) error {
 		}
 	}
 
+	if len(tempSeries) == 0 {
+		return nil
+	}
+
 	redactedApiKey := "****************"
 	ts.Series = make([]*Metric, metricCounter)
 	copy(ts.Series, tempSeries[0:])
@@ -166,9 +172,12 @@ func buildTags(tagList []*telegraf.Tag) []string {
 }
 
 func verifyValue(v interface{}) bool {
-	switch v.(type) {
+	switch v := v.(type) {
 	case string:
 		return false
+	case float64:
+		// The payload will be encoded as JSON, which does not allow NaN or Inf.
+		return !math.IsNaN(v) && !math.IsInf(v, 0)
 	}
 	return true
 }
diff --git a/plugins/outputs/datadog/datadog_test.go b/plugins/outputs/datadog/datadog_test.go
index 7bbc91254..be8541ee8 100644
--- a/plugins/outputs/datadog/datadog_test.go
+++ b/plugins/outputs/datadog/datadog_test.go
@@ -3,15 +3,15 @@ package datadog
 import (
 	"encoding/json"
 	"fmt"
+	"math"
 	"net/http"
 	"net/http/httptest"
 	"reflect"
 	"testing"
 	"time"
 
-	"github.com/influxdata/telegraf/testutil"
-
 	"github.com/influxdata/telegraf"
+	"github.com/influxdata/telegraf/testutil"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 )
@@ -249,3 +249,45 @@ func TestVerifyValue(t *testing.T) {
 		}
 	}
 }
+
+func TestNaNIsSkipped(t *testing.T) {
+	plugin := &Datadog{
+		Apikey: "testing",
+		URL:    "", // No request will be sent because all fields are skipped
+	}
+
+	err := plugin.Connect()
+	require.NoError(t, err)
+
+	err = plugin.Write([]telegraf.Metric{
+		testutil.MustMetric(
+			"cpu",
+			map[string]string{},
+			map[string]interface{}{
+				"time_idle": math.NaN(),
+			},
+			time.Now()),
+	})
+	require.NoError(t, err)
+}
+
+func TestInfIsSkipped(t *testing.T) {
+	plugin := &Datadog{
+		Apikey: "testing",
+		URL:    "", // No request will be sent because all fields are skipped
+	}
+
+	err := plugin.Connect()
+	require.NoError(t, err)
+
+	err = plugin.Write([]telegraf.Metric{
+		testutil.MustMetric(
+			"cpu",
+			map[string]string{},
+			map[string]interface{}{
+				"time_idle": math.Inf(0),
+			},
+			time.Now()),
+	})
+	require.NoError(t, err)
+}