Add PoC of git clone/fetch requests metric

internal/helper/logging.go

@@ -7,6 +7,7 @@ import (
 	"net/http"
 	"os"
 	"strconv"
+	"strings"
 	"time"
 
 	"github.com/prometheus/client_golang/prometheus"
@@ -27,6 +28,14 @@ var (
 		},
 		[]string{"code", "method"},
 	)
+
+	cloneFetchRequests = prometheus.NewCounterVec(
+		prometheus.CounterOpts{
+			Name: "gitlab_workhorse_git_clone_fetch_requests",
+			Help: "How many Git clone/fetch requests for CI have been processed by gitlab-workhorse, partitioned by CI yes/no status.",
+		},
+		[]string{"ci"},
+	)
 )
 
 func init() {
@@ -41,6 +50,7 @@ func SetCustomResponseLogger(writer io.Writer) {
 func registerPrometheusMetrics() {
 	prometheus.MustRegister(sessionsActive)
 	prometheus.MustRegister(requestsTotal)
+	prometheus.MustRegister(cloneFetchRequests)
 }
 
 type LoggingResponseWriter struct {
@@ -88,6 +98,24 @@ func (l *LoggingResponseWriter) Log(r *http.Request) {
 		l.status, l.written, r.Referer(), r.UserAgent(), duration.Seconds(),
 	)
 
+	l.countCloneFetchRequests(r)
+
 	sessionsActive.Dec()
 	requestsTotal.WithLabelValues(strconv.Itoa(l.status), r.Method).Inc()
 }
+
+func (l *LoggingResponseWriter) countCloneFetchRequests(r *http.Request) {
+	if l.status == 401 || !strings.Contains(r.RequestURI, "/info/refs?service=git-upload-pack") {
+		return
+	}
+
+	u, _, ok := r.BasicAuth()
+	var forCi string
+	if ok && u == "gitlab-ci-token" {
+		forCi = "1"
+	} else {
+		forCi = "0"
+	}
+
+	cloneFetchRequests.WithLabelValues(forCi).Inc()
+}