Rename Headers struct members to ProxyHeader

The Headers slice is only ever used for an optional PROXY protocol header, and was easy to confuse with HTTP headers. Signed-off-by: Daniel Swarbrick <[email protected]>
boynux · Sep 16, 2024 · ac01f1c · ac01f1c
1 parent 4fa6677
commit ac01f1c
Show file tree

Hide file tree

Showing 4 changed files with 31 additions and 28 deletions.
diff --git a/collector/client.go b/collector/client.go
@@ -20,7 +20,7 @@ import (
 type CacheObjectClient struct {
 	ch              connectionHandler
 	basicAuthString string
-	headers         []string
+	proxyHeader     string
 }
 
 type connectionHandler interface {
@@ -48,11 +48,11 @@ func buildBasicAuthString(login string, password string) string {
 }
 
 type CacheObjectRequest struct {
-	Hostname string
-	Port     int
-	Login    string
-	Password string
-	Headers  []string
+	Hostname    string
+	Port        int
+	Login       string
+	Password    string
+	ProxyHeader string
 }
 
 /*NewCacheObjectClient initializes a new cache client */
@@ -63,7 +63,7 @@ func NewCacheObjectClient(cor *CacheObjectRequest) *CacheObjectClient {
 			cor.Port,
 		},
 		buildBasicAuthString(cor.Login, cor.Password),
-		cor.Headers,
+		cor.ProxyHeader,
 	}
 }
 
@@ -73,7 +73,7 @@ func (c *CacheObjectClient) readFromSquid(endpoint string) (*bufio.Reader, error
 	if err != nil {
 		return nil, err
 	}
-	r, err := get(conn, endpoint, c.basicAuthString, c.headers)
+	r, err := get(conn, endpoint, c.basicAuthString, c.proxyHeader)
 
 	if err != nil {
 		return nil, err
@@ -207,11 +207,12 @@ func (ch *connectionHandlerImpl) connect() (net.Conn, error) {
 	return net.Dial("tcp", fmt.Sprintf("%s:%d", ch.hostname, ch.port))
 }
 
-func get(conn net.Conn, path string, basicAuthString string, headers []string) (*http.Response, error) {
+func get(conn net.Conn, path, basicAuthString, proxyHeader string) (*http.Response, error) {
 	var buf bytes.Buffer
 
-	for _, h := range headers {
-		fmt.Fprintf(&buf, "%s\r\n", h)
+	if proxyHeader != "" {
+		buf.WriteString(proxyHeader)
+		buf.WriteString("\r\n")
 	}
 
 	fmt.Fprintf(&buf, "GET cache_object://localhost/%s HTTP/1.0\r\n", path)

diff --git a/collector/client_test.go b/collector/client_test.go
@@ -46,9 +46,11 @@ func TestReadFromSquid(t *testing.T) {
 	coc := &CacheObjectClient{
 		ch,
 		"",
-		[]string{},
+		"",
 	}
-	expected := "GET cache_object://localhost/test HTTP/1.0\r\nHost: localhost\r\nUser-Agent: squidclient/3.5.12\r\nAccept: */*\r\n\r\n"
+	// This test is overly brittle; the order of HTTP headers is not significant. Go sorts headers
+	// lexicographically when calling http.Header.Write().
+	expected := "GET cache_object://localhost/test HTTP/1.0\r\nAccept: */*\r\nHost: localhost\r\nUser-Agent: squidclient/3.5.12\r\n\r\n"
 	coc.readFromSquid("test")
 
 	assert.Equal(t, expected, string(ch.buffer))

diff --git a/collector/metrics.go b/collector/metrics.go
@@ -34,12 +34,12 @@ type Exporter struct {
 }
 
 type CollectorConfig struct {
-	Hostname string
-	Port     int
-	Login    string
-	Password string
-	Labels   config.Labels
-	Headers  []string
+	Hostname    string
+	Port        int
+	Login       string
+	Password    string
+	Labels      config.Labels
+	ProxyHeader string
 }
 
 /*New initializes a new exporter */
@@ -57,7 +57,7 @@ func New(c *CollectorConfig) *Exporter {
 			c.Port,
 			c.Login,
 			c.Password,
-			c.Headers,
+			c.ProxyHeader,
 		}),
 
 		c.Hostname,

diff --git a/main.go b/main.go
@@ -31,20 +31,20 @@ func main() {
 	}
 	collector.ExtractServiceTimes = cfg.ExtractServiceTimes
 
-	headers := []string{}
+	proxyHeader := ""
 
 	if cfg.UseProxyHeader {
-		headers = append(headers, createProxyHeader(cfg))
+		proxyHeader = createProxyHeader(cfg)
 	}
 
 	log.Println("Scraping metrics from", fmt.Sprintf("%s:%d", cfg.SquidHostname, cfg.SquidPort))
 	e := collector.New(&collector.CollectorConfig{
-		Hostname: cfg.SquidHostname,
-		Port:     cfg.SquidPort,
-		Login:    cfg.Login,
-		Password: cfg.Password,
-		Labels:   cfg.Labels,
-		Headers:  headers,
+		Hostname:    cfg.SquidHostname,
+		Port:        cfg.SquidPort,
+		Login:       cfg.Login,
+		Password:    cfg.Password,
+		Labels:      cfg.Labels,
+		ProxyHeader: proxyHeader,
 	})
 	prometheus.MustRegister(e)