Track total and active requests

internal/helper/logging.go

@@ -6,7 +6,10 @@ import (
 	"log"
 	"net/http"
 	"os"
+	"strconv"
 	"time"
+
+	"gitlab.com/gitlab-org/gitlab-workhorse/internal/metrics"
 )
 
 var responseLogger *log.Logger
@@ -27,6 +30,7 @@ type LoggingResponseWriter struct {
 }
 
 func NewLoggingResponseWriter(rw http.ResponseWriter) LoggingResponseWriter {
+	metrics.RequestsActive.Inc()
 	return LoggingResponseWriter{
 		rw:      rw,
 		started: time.Now(),
@@ -62,4 +66,7 @@ func (l *LoggingResponseWriter) Log(r *http.Request) {
 		fmt.Sprintf("%s %s %s", r.Method, r.RequestURI, r.Proto),
 		l.status, l.written, r.Referer(), r.UserAgent(), duration.Seconds(),
 	)
+
+	metrics.RequestsActive.Dec()
+	metrics.RequestsTotal.WithLabelValues(strconv.Itoa(l.status), r.Method).Inc()
 }

internal/metrics/metrics.go

+package metrics
+
+import (
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+var (
+	RequestsActive = prometheus.NewGauge(prometheus.GaugeOpts{
+		Name: "http_requests_active",
+		Help: "Number of HTTP requests currently being handled.",
+	})
+	RequestsTotal = prometheus.NewCounterVec(
+		prometheus.CounterOpts{
+			Name: "http_requests_total",
+			Help: "How many HTTP requests processed, partitioned by status code and HTTP method.",
+		},
+		[]string{"code", "method"},
+	)
+)
+
+func init() {
+	prometheus.MustRegister(RequestsActive)
+	prometheus.MustRegister(RequestsTotal)
+}