From b2eb7740494995d03479a21304a4a794cc380d4a Mon Sep 17 00:00:00 2001
From: Steven Soroka <ssoroka@influxdata.com>
Date: Fri, 14 Aug 2020 13:43:31 -0400
Subject: [PATCH] http_listener_v2: make http header tags case insensitive
 (#7986)

---
 plugins/inputs/http_listener_v2/http_listener_v2.go      | 6 +++---
 plugins/inputs/http_listener_v2/http_listener_v2_test.go | 2 +-
 testutil/log.go                                          | 4 ++++
 3 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/plugins/inputs/http_listener_v2/http_listener_v2.go b/plugins/inputs/http_listener_v2/http_listener_v2.go
index 93ab72d26..1023c0d10 100644
--- a/plugins/inputs/http_listener_v2/http_listener_v2.go
+++ b/plugins/inputs/http_listener_v2/http_listener_v2.go
@@ -232,9 +232,9 @@ func (h *HTTPListenerV2) serveWrite(res http.ResponseWriter, req *http.Request)
 
 	for _, m := range metrics {
 		for headerName, measurementName := range h.HTTPHeaderTags {
-			headerValues, foundHeader := req.Header[headerName]
-			if foundHeader && len(headerValues) > 0 {
-				m.AddTag(measurementName, headerValues[0])
+			headerValues := req.Header.Get(headerName)
+			if len(headerValues) > 0 {
+				m.AddTag(measurementName, headerValues)
 			}
 		}
 
diff --git a/plugins/inputs/http_listener_v2/http_listener_v2_test.go b/plugins/inputs/http_listener_v2/http_listener_v2_test.go
index 52af1b963..4457fcacd 100644
--- a/plugins/inputs/http_listener_v2/http_listener_v2_test.go
+++ b/plugins/inputs/http_listener_v2/http_listener_v2_test.go
@@ -383,7 +383,7 @@ func TestWriteHTTPEmpty(t *testing.T) {
 
 func TestWriteHTTPTransformHeaderValuesToTagsSingleWrite(t *testing.T) {
 	listener := newTestHTTPListenerV2()
-	listener.HTTPHeaderTags = map[string]string{"Present_http_header_1": "presentMeasurementKey1", "Present_http_header_2": "presentMeasurementKey2", "NOT_PRESENT_HEADER": "notPresentMeasurementKey"}
+	listener.HTTPHeaderTags = map[string]string{"Present_http_header_1": "presentMeasurementKey1", "present_http_header_2": "presentMeasurementKey2", "NOT_PRESENT_HEADER": "notPresentMeasurementKey"}
 
 	acc := &testutil.Accumulator{}
 	require.NoError(t, listener.Start(acc))
diff --git a/testutil/log.go b/testutil/log.go
index 5e0458dc7..c81370e23 100644
--- a/testutil/log.go
+++ b/testutil/log.go
@@ -2,8 +2,12 @@ package testutil
 
 import (
 	"log"
+
+	"github.com/influxdata/telegraf"
 )
 
+var _ telegraf.Logger = &Logger{}
+
 // Logger defines a logging structure for plugins.
 type Logger struct {
 	Name string // Name is the plugin name, will be printed in the `[]`.