From e21588702f83bffa4181b59a477b73c4c5ec1a35 Mon Sep 17 00:00:00 2001
From: Asher Foa <1268088+asherf@users.noreply.github.com>
Date: Thu, 31 Oct 2019 10:11:41 -0700
Subject: [PATCH] set user agent on scrape requests to nginx.

---
 CHANGELOG.md    |  5 +++++
 client/nginx.go | 12 ++++++++++--
 exporter.go     |  3 ++-
 3 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 0d9fac4c..b02d55bb 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,10 @@
 # Changelog
 
+### DEV
+
+FEATURES:
+* Set User-Agent header when calling the nginx stats endpoint.
+
 ### 0.4.2
 
 BUGFIXES:
diff --git a/client/nginx.go b/client/nginx.go
index c186634b..9d76929c 100644
--- a/client/nginx.go
+++ b/client/nginx.go
@@ -12,6 +12,7 @@ import (
 type NginxClient struct {
 	apiEndpoint string
 	httpClient  *http.Client
+	appName	string
 }
 
 // StubStats represents NGINX stub_status metrics.
@@ -31,10 +32,11 @@ type StubConnections struct {
 }
 
 // NewNginxClient creates an NginxClient.
-func NewNginxClient(httpClient *http.Client, apiEndpoint string) (*NginxClient, error) {
+func NewNginxClient(httpClient *http.Client, apiEndpoint string, appName string) (*NginxClient, error) {
 	client := &NginxClient{
 		apiEndpoint: apiEndpoint,
 		httpClient:  httpClient,
+		appName: appName,
 	}
 
 	_, err := client.GetStubStats()
@@ -43,7 +45,13 @@ func NewNginxClient(httpClient *http.Client, apiEndpoint string) (*NginxClient,
 
 // GetStubStats fetches the stub_status metrics.
 func (client *NginxClient) GetStubStats() (*StubStats, error) {
-	resp, err := client.httpClient.Get(client.apiEndpoint)
+
+	req, err := http.NewRequest("GET", client.apiEndpoint, nil)
+	if err != nil {
+			return nil, fmt.Errorf("failed to create get request %v: %v", client.apiEndpoint, err)
+	}
+	req.Header.Set("User-Agent", client.appName)
+	resp, err := client.httpClient.Do(req)
 	if err != nil {
 		return nil, fmt.Errorf("failed to get %v: %v", client.apiEndpoint, err)
 	}
diff --git a/exporter.go b/exporter.go
index 30629da7..0ba0aca9 100644
--- a/exporter.go
+++ b/exporter.go
@@ -200,8 +200,9 @@ func main() {
 		}
 		registry.MustRegister(collector.NewNginxPlusCollector(plusClient.(*plusclient.NginxClient), "nginxplus"))
 	} else {
+		appName := fmt.Sprintf("NGINX-Prometheus-Exporter/v%v", version)
 		ossClient, err := createClientWithRetries(func() (interface{}, error) {
-			return client.NewNginxClient(httpClient, *scrapeURI)
+			return client.NewNginxClient(httpClient, *scrapeURI, appName)
 		}, *nginxRetries, nginxRetryInterval.Duration)
 		if err != nil {
 			log.Fatalf("Could not create Nginx Client: %v", err)