fix(metrics): strip urls for login counter

pkg/handler/handler.go

@@ -7,7 +7,6 @@ import (
 	"fmt"
 	"net/http"
 	urllib "net/url"
-	"strings"
 	"time"
 
 	"github.com/sethvargo/go-retry"
@@ -215,7 +214,7 @@ func (s *Standalone) LoginCallback(w http.ResponseWriter, r *http.Request) {
 	}
 
 	mw.LogEntryFrom(r).WithFields(fields).Info("callback: successful login")
-	metrics.ObserveLogin(tokens.IDToken.GetAmrClaim(), strings.TrimSuffix(redirect, "/"))
+	metrics.ObserveLogin(tokens.IDToken.GetAmrClaim(), redirect)
 	cookie.Clear(w, cookie.Retry, s.GetCookieOptions(r))
 	http.Redirect(w, r, redirect, http.StatusTemporaryRedirect)
 }

pkg/metrics/metrics.go

@@ -2,6 +2,8 @@ package metrics
 
 import (
 	"net/http"
+	"net/url"
+	"strings"
 	"time"
 
 	"github.com/prometheus/client_golang/prometheus"
@@ -153,6 +155,14 @@ func ObserveRedisLatency(operation string, fun func() error) error {
 }
 
 func ObserveLogin(amrValue, redirect string) {
+	u, err := url.Parse(redirect)
+	if err == nil {
+		u.Path = strings.TrimSuffix(u.Path, "/")
+		u.RawQuery = ""
+		u.RawFragment = ""
+		redirect = u.String()
+	}
+
 	Logins.With(prometheus.Labels{
 		LabelAmr:      amrValue,
 		LabelRedirect: redirect,