From 422c142463d16912ab033e135ca05a77c8a2be1a Mon Sep 17 00:00:00 2001
From: Kevin Conaway <kevin.a.conaway@gmail.com>
Date: Fri, 5 Oct 2018 16:48:18 -0400
Subject: [PATCH] Use non-allocating field and tag accessors in datadog output
 (#4803)

---
 plugins/outputs/datadog/datadog.go      | 27 ++++++++++++-------------
 plugins/outputs/datadog/datadog_test.go | 22 ++++++++++++++++----
 2 files changed, 31 insertions(+), 18 deletions(-)

diff --git a/plugins/outputs/datadog/datadog.go b/plugins/outputs/datadog/datadog.go
index 2ab3dcd580bbe..2ef03a7b241e7 100644
--- a/plugins/outputs/datadog/datadog.go
+++ b/plugins/outputs/datadog/datadog.go
@@ -7,7 +7,6 @@ import (
 	"log"
 	"net/http"
 	"net/url"
-	"sort"
 	"strings"
 
 	"github.com/influxdata/telegraf"
@@ -76,6 +75,9 @@ func (d *Datadog) Write(metrics []telegraf.Metric) error {
 
 	for _, m := range metrics {
 		if dogMs, err := buildMetrics(m); err == nil {
+			metricTags := buildTags(m.TagList())
+			host, _ := m.GetTag("host")
+
 			for fieldName, dogM := range dogMs {
 				// name of the datadog measurement
 				var dname string
@@ -85,11 +87,9 @@ func (d *Datadog) Write(metrics []telegraf.Metric) error {
 				} else {
 					dname = m.Name() + "." + fieldName
 				}
-				var host string
-				host, _ = m.Tags()["host"]
 				metric := &Metric{
 					Metric: dname,
-					Tags:   buildTags(m.Tags()),
+					Tags:   metricTags,
 					Host:   host,
 				}
 				metric.Points[0] = dogM
@@ -144,28 +144,27 @@ func (d *Datadog) authenticatedUrl() string {
 
 func buildMetrics(m telegraf.Metric) (map[string]Point, error) {
 	ms := make(map[string]Point)
-	for k, v := range m.Fields() {
-		if !verifyValue(v) {
+	for _, field := range m.FieldList() {
+		if !verifyValue(field.Value) {
 			continue
 		}
 		var p Point
-		if err := p.setValue(v); err != nil {
-			return ms, fmt.Errorf("unable to extract value from Fields %v error %v", k, err.Error())
+		if err := p.setValue(field.Value); err != nil {
+			return ms, fmt.Errorf("unable to extract value from Fields %v error %v", field.Key, err.Error())
 		}
 		p[0] = float64(m.Time().Unix())
-		ms[k] = p
+		ms[field.Key] = p
 	}
 	return ms, nil
 }
 
-func buildTags(mTags map[string]string) []string {
-	tags := make([]string, len(mTags))
+func buildTags(tagList []*telegraf.Tag) []string {
+	tags := make([]string, len(tagList))
 	index := 0
-	for k, v := range mTags {
-		tags[index] = fmt.Sprintf("%s:%s", k, v)
+	for _, tag := range tagList {
+		tags[index] = fmt.Sprintf("%s:%s", tag.Key, tag.Value)
 		index += 1
 	}
-	sort.Strings(tags)
 	return tags
 }
 
diff --git a/plugins/outputs/datadog/datadog_test.go b/plugins/outputs/datadog/datadog_test.go
index 045bf4b435b93..f21ecc5887a9a 100644
--- a/plugins/outputs/datadog/datadog_test.go
+++ b/plugins/outputs/datadog/datadog_test.go
@@ -74,19 +74,33 @@ func TestAuthenticatedUrl(t *testing.T) {
 
 func TestBuildTags(t *testing.T) {
 	var tagtests = []struct {
-		ptIn    map[string]string
+		ptIn    []*telegraf.Tag
 		outTags []string
 	}{
 		{
-			map[string]string{"one": "two", "three": "four"},
+			[]*telegraf.Tag{
+				&telegraf.Tag{
+					Key:   "one",
+					Value: "two",
+				},
+				&telegraf.Tag{
+					Key:   "three",
+					Value: "four",
+				},
+			},
 			[]string{"one:two", "three:four"},
 		},
 		{
-			map[string]string{"aaa": "bbb"},
+			[]*telegraf.Tag{
+				&telegraf.Tag{
+					Key:   "aaa",
+					Value: "bbb",
+				},
+			},
 			[]string{"aaa:bbb"},
 		},
 		{
-			map[string]string{},
+			[]*telegraf.Tag{},
 			[]string{},
 		},
 	}