feat: add support for custom headers

README.md

@@ -24,6 +24,7 @@ Help on flags:
       --host_override=""   Override for HTTP Host header; empty string for no
                            override.
       --insecure           Ignore server certificate if using https.
+      --custom_headers     Adds custom headers to the collector.
       --web.config=""      Path to config yaml file that can enable TLS or
                            authentication.
       --log.level=info     Only log messages with the given severity or above.

apache_exporter.go

@@ -32,6 +32,7 @@ var (
 	scrapeURI        = kingpin.Flag("scrape_uri", "URI to apache stub status page.").Default("http://localhost/server-status/?auto").String()
 	hostOverride     = kingpin.Flag("host_override", "Override for HTTP Host header; empty string for no override.").Default("").String()
 	insecure         = kingpin.Flag("insecure", "Ignore server certificate if using https.").Bool()
+	customHeaders    = kingpin.Flag("custom_headers", "Adds custom headers to the collector.").StringMap()
 	configFile       = kingpin.Flag("web.config", "Path to config yaml file that can enable TLS or authentication.").Default("").String()
 	gracefulStop     = make(chan os.Signal, 1)
 )
@@ -53,9 +54,10 @@ func main() {
 	signal.Notify(gracefulStop, syscall.SIGQUIT)
 
 	config := &collector.Config{
-		ScrapeURI:    *scrapeURI,
-		HostOverride: *hostOverride,
-		Insecure:     *insecure,
+		ScrapeURI:     *scrapeURI,
+		HostOverride:  *hostOverride,
+		Insecure:      *insecure,
+		CustomHeaders: *customHeaders,
 	}
 
 	webSystemdSocket := false

apache_exporter_test.go

@@ -273,9 +273,10 @@ func checkApacheStatus(t *testing.T, status string, metricCount int) {
 	promlogConfig := &promlog.Config{}
 	logger := promlog.New(promlogConfig)
 	config := &collector.Config{
-		ScrapeURI:    server.URL,
-		HostOverride: "",
-		Insecure:     false,
+		ScrapeURI:     server.URL,
+		HostOverride:  "",
+		Insecure:      false,
+		CustomHeaders: map[string]string{"Cookie": "A test cookie"},
 	}
 	e := collector.NewExporter(logger, config)
 	ch := make(chan prometheus.Metric)

collector/collector.go

@@ -26,10 +26,11 @@ const (
 )
 
 type Exporter struct {
-	URI          string
-	hostOverride string
-	mutex        sync.Mutex
-	client       *http.Client
+	URI           string
+	hostOverride  string
+	customHeaders map[string]string
+	mutex         sync.Mutex
+	client        *http.Client
 
 	up                    *prometheus.Desc
 	scrapeFailures        prometheus.Counter
@@ -56,16 +57,18 @@ type Exporter struct {
 }
 
 type Config struct {
-	ScrapeURI    string
-	HostOverride string
-	Insecure     bool
+	ScrapeURI     string
+	HostOverride  string
+	Insecure      bool
+	CustomHeaders map[string]string
 }
 
 func NewExporter(logger log.Logger, config *Config) *Exporter {
 	return &Exporter{
-		URI:          config.ScrapeURI,
-		hostOverride: config.HostOverride,
-		logger:       logger,
+		URI:           config.ScrapeURI,
+		hostOverride:  config.HostOverride,
+		customHeaders: config.CustomHeaders,
+		logger:        logger,
 		up: prometheus.NewDesc(
 			prometheus.BuildFQName(namespace, "", "up"),
 			"Could the apache server be reached",
@@ -276,6 +279,9 @@ func (e *Exporter) collect(ch chan<- prometheus.Metric) error {
 	if err != nil {
 		return fmt.Errorf("error building scraping request: %v", err)
 	}
+	for k, v := range e.customHeaders {
+		req.Header.Add(k, v)
+	}
 	resp, err := e.client.Do(req)
 	if err != nil {
 		ch <- prometheus.MustNewConstMetric(e.up, prometheus.GaugeValue, 0)