1 files changed, 38 insertions, 0 deletions
diff --git a/workhorse/internal/rejectmethods/middleware.go b/workhorse/internal/rejectmethods/middleware.go
new file mode 100644
index 00000000000..171463979d5
--- /dev/null
+++ b/workhorse/internal/rejectmethods/middleware.go
@@ -0,0 +1,38 @@
+package rejectmethods
+
+import (
+	"net/http"
+
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+var acceptedMethods = map[string]bool{
+	http.MethodGet:     true,
+	http.MethodHead:    true,
+	http.MethodPost:    true,
+	http.MethodPut:     true,
+	http.MethodPatch:   true,
+	http.MethodDelete:  true,
+	http.MethodConnect: true,
+	http.MethodOptions: true,
+	http.MethodTrace:   true,
+}
+
+var rejectedRequestsCount = prometheus.NewCounter(
+	prometheus.CounterOpts{
+		Name: "gitlab_workhorse_unknown_method_rejected_requests",
+		Help: "The number of requests with unknown HTTP method which were rejected",
+	},
+)
+
+// NewMiddleware returns middleware which rejects all unknown http methods
+func NewMiddleware(handler http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if acceptedMethods[r.Method] {
+			handler.ServeHTTP(w, r)
+		} else {
+			rejectedRequestsCount.Inc()
+			http.Error(w, http.StatusText(http.StatusMethodNotAllowed), http.StatusMethodNotAllowed)
+		}
+	})
+}