outposts: make metrics compliant with Prometheus best-practices (#6398)

web/outpost: make metrics compliant with Prometheus best-practices

Today, all NewHistogramVec store values in nanoseconds without changing
the default histogram bucket, which are made for seconds, making them
a bit useless. In addition, some metrics names are not self-explanatoryand
and do not comply with Prometheus best practices.

This commit tries to fix all of this "issues".

NOTE: I kept old metrics in order to avoid breaking changes with
existing dashboards and metrics.

Signed-off-by: Alexandre NICOLAIE <xunleii@users.noreply.github.com>

internal/outpost/ldap/bind.go

@@ -2,6 +2,7 @@ package ldap
 
 import (
 	"net"
+	"time"
 
 	"beryju.io/ldap"
 	"github.com/getsentry/sentry-go"
@@ -20,6 +21,11 @@ func (ls *LDAPServer) Bind(bindDN string, bindPW string, conn net.Conn) (ldap.LD
 			"outpost_name": ls.ac.Outpost.Name,
 			"type":         "bind",
 			"app":          selectedApp,
+		}).Observe(float64(span.EndTime.Sub(span.StartTime)) / float64(time.Second))
+		metrics.RequestsLegacy.With(prometheus.Labels{
+			"outpost_name": ls.ac.Outpost.Name,
+			"type":         "bind",
+			"app":          selectedApp,
 		}).Observe(float64(span.EndTime.Sub(span.StartTime)))
 		req.Log().WithField("took-ms", span.EndTime.Sub(span.StartTime).Milliseconds()).Info("Bind request")
 	}()
@@ -49,6 +55,12 @@ func (ls *LDAPServer) Bind(bindDN string, bindPW string, conn net.Conn) (ldap.LD
 		"reason":       "no_provider",
 		"app":          "",
 	}).Inc()
+	metrics.RequestsRejectedLegacy.With(prometheus.Labels{
+		"outpost_name": ls.ac.Outpost.Name,
+		"type":         "bind",
+		"reason":       "no_provider",
+		"app":          "",
+	}).Inc()
 
 	return ldap.LDAPResultInsufficientAccessRights, nil
 }