From f14d2a087f7b0fd6f7980b95b5e0b945109c95f3 Mon Sep 17 00:00:00 2001
From: shawwang <shawwang@tencent.com>
Date: Mon, 24 Feb 2020 15:47:45 +0800
Subject: [PATCH] auth: add new metric 'etcd_debugging_auth_revision'

---
 auth/metrics.go | 42 ++++++++++++++++++++++++++++++++++++++++++
 auth/store.go   | 10 ++++++++++
 2 files changed, 52 insertions(+)
 create mode 100644 auth/metrics.go

diff --git a/auth/metrics.go b/auth/metrics.go
new file mode 100644
index 00000000000..fe0d28e22d5
--- /dev/null
+++ b/auth/metrics.go
@@ -0,0 +1,42 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package auth
+
+import (
+	"github.com/prometheus/client_golang/prometheus"
+	"sync"
+)
+
+var (
+	currentAuthRevision = prometheus.NewGaugeFunc(prometheus.GaugeOpts{
+		Namespace: "etcd_debugging",
+		Subsystem: "auth",
+		Name:      "revision",
+		Help:      "The current revision of auth store.",
+	},
+		func() float64 {
+			reportCurrentAuthRevMu.RLock()
+			defer reportCurrentAuthRevMu.RUnlock()
+			return reportCurrentAuthRev()
+		},
+	)
+	// overridden by auth store initialization
+	reportCurrentAuthRevMu sync.RWMutex
+	reportCurrentAuthRev   = func() float64 { return 0 }
+)
+
+func init() {
+	prometheus.MustRegister(currentAuthRevision)
+}
diff --git a/auth/store.go b/auth/store.go
index 5c6d37dbe0a..5672a9440e1 100644
--- a/auth/store.go
+++ b/auth/store.go
@@ -1068,6 +1068,8 @@ func NewAuthStore(lg *zap.Logger, be backend.Backend, tp TokenProvider, bcryptCo
 		as.saveConsistentIndex(tx)
 	}
 
+	as.setupMetricsReporter()
+
 	tx.Unlock()
 	be.ForceCommit()
 
@@ -1318,3 +1320,11 @@ func (as *authStore) saveConsistentIndex(tx backend.BatchTx) {
 		as.lg.Error("failed to save consistentIndex,syncConsistentIndex is nil")
 	}
 }
+
+func (as *authStore) setupMetricsReporter() {
+	reportCurrentAuthRevMu.Lock()
+	reportCurrentAuthRev = func() float64 {
+		return float64(as.Revision())
+	}
+	reportCurrentAuthRevMu.Unlock()
+}