feat: Export metrics to track number of users (#20801) (#23343)

Signed-off-by: Sathiya Narayanan Venkatesan <sathiyavenkat06@gmail.com>
Signed-off-by: sathiya06 <64639742+sathiya06@users.noreply.github.com>

server/metrics/metrics.go

@@ -20,6 +20,7 @@ type MetricsServer struct {
 	redisRequestHistogram    *prometheus.HistogramVec
 	extensionRequestCounter  *prometheus.CounterVec
 	extensionRequestDuration *prometheus.HistogramVec
+	loginRequestCounter      *prometheus.CounterVec
 }
 
 var (
@@ -53,6 +54,13 @@ var (
 		},
 		[]string{"extension"},
 	)
+	loginRequestCounter = prometheus.NewCounterVec(
+		prometheus.CounterOpts{
+			Name: "argocd_login_request_total",
+			Help: "Number of login requests to the Argo CD API server.",
+		},
+		[]string{"status"},
+	)
 	argoVersion = prometheus.NewGaugeVec(
 		prometheus.GaugeOpts{
 			Name: "argocd_info",
@@ -78,6 +86,7 @@ func NewMetricsServer(host string, port int) *MetricsServer {
 	registry.MustRegister(redisRequestHistogram)
 	registry.MustRegister(extensionRequestCounter)
 	registry.MustRegister(extensionRequestDuration)
+	registry.MustRegister(loginRequestCounter)
 	registry.MustRegister(argoVersion)
 
 	kubectl.RegisterWithClientGo()
@@ -92,6 +101,7 @@ func NewMetricsServer(host string, port int) *MetricsServer {
 		redisRequestHistogram:    redisRequestHistogram,
 		extensionRequestCounter:  extensionRequestCounter,
 		extensionRequestDuration: extensionRequestDuration,
+		loginRequestCounter:      loginRequestCounter,
 	}
 }
 
@@ -111,3 +121,9 @@ func (m *MetricsServer) IncExtensionRequestCounter(extension string, status int)
 func (m *MetricsServer) ObserveExtensionRequestDuration(extension string, duration time.Duration) {
 	m.extensionRequestDuration.WithLabelValues(extension).Observe(duration.Seconds())
 }
+
+// IncLoginRequestCounter increments the login request counter with the given status
+// status can be "success" or "failure"
+func (m *MetricsServer) IncLoginRequestCounter(status string) {
+	m.loginRequestCounter.WithLabelValues(status).Inc()
+}

server/server.go

@@ -573,6 +573,9 @@ func (server *ArgoCDServer) Run(ctx context.Context, listeners *Listeners) {
 	server.userStateStorage.Init(ctx)
 
 	svcSet := newArgoCDServiceSet(server)
+	if server.sessionMgr != nil {
+		server.sessionMgr.CollectMetrics(metricsServ)
+	}
 	server.serviceSet = svcSet
 	grpcS, appResourceTreeFn := server.newGRPCServer()
 	grpcWebS := grpcweb.WrapServer(grpcS)

server/session/session.go

@@ -29,6 +29,11 @@ type Authenticator interface {
 	Authenticate(ctx context.Context) (context.Context, error)
 }
 
+const (
+	success = "success"
+	failure = "failure"
+)
+
 // NewServer returns a new instance of the Session service
 func NewServer(mgr *sessionmgr.SessionManager, settingsMgr *settings.SettingsManager, authenticator Authenticator, policyEnf *rbacpolicy.RBACPolicyEnforcer, rateLimiter func() (utilio.Closer, error)) *Server {
 	return &Server{mgr, settingsMgr, authenticator, policyEnf, rateLimiter}
@@ -40,27 +45,33 @@ func (s *Server) Create(_ context.Context, q *session.SessionCreateRequest) (*se
 	if s.limitLoginAttempts != nil {
 		closer, err := s.limitLoginAttempts()
 		if err != nil {
+			s.mgr.IncLoginRequestCounter(failure)
 			return nil, err
 		}
 		defer utilio.Close(closer)
 	}
 
 	if q.Token != "" {
+		s.mgr.IncLoginRequestCounter(failure)
 		return nil, status.Errorf(codes.Unauthenticated, "token-based session creation no longer supported. please upgrade argocd cli to v0.7+")
 	}
 	if q.Username == "" || q.Password == "" {
+		s.mgr.IncLoginRequestCounter(failure)
 		return nil, status.Errorf(codes.Unauthenticated, "no credentials supplied")
 	}
 	err := s.mgr.VerifyUsernamePassword(q.Username, q.Password)
 	if err != nil {
+		s.mgr.IncLoginRequestCounter(failure)
 		return nil, err
 	}
 	uniqueId, err := uuid.NewRandom()
 	if err != nil {
+		s.mgr.IncLoginRequestCounter(failure)
 		return nil, err
 	}
 	argoCDSettings, err := s.settingsMgr.GetSettings()
 	if err != nil {
+		s.mgr.IncLoginRequestCounter(failure)
 		return nil, err
 	}
 	jwtToken, err := s.mgr.Create(
@@ -68,8 +79,10 @@ func (s *Server) Create(_ context.Context, q *session.SessionCreateRequest) (*se
 		int64(argoCDSettings.UserSessionDuration.Seconds()),
 		uniqueId.String())
 	if err != nil {
+		s.mgr.IncLoginRequestCounter(failure)
 		return nil, err
 	}
+	s.mgr.IncLoginRequestCounter(success)
 	return &session.SessionResponse{Token: jwtToken}, nil
 }