Use histograms instead of gagues

Removed test assertion for metric as histograms are not collectors
so we can't really test it. Left the test though as it's still valuable.

1 files changed, 1 insertions, 1 deletions

diff --git a/app.go b/app.go
index 38744e93..7b1749a6 100644
--- a/app.go
+++ b/app.go
@@ -259,7 +259,7 @@ func (a *theApp) accessControlMiddleware(handler http.Handler) http.Handler {
 func (a *theApp) serveFileOrNotFoundHandler() http.Handler {
 	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		start := time.Now()
-		defer metrics.ServingTime.Set(time.Since(start).Seconds())
+		defer metrics.ServingTime.Observe(time.Since(start).Seconds())
 
 		domain := request.GetDomain(r)
 		fileServed := domain.ServeFileHTTP(w, r)