From 9adfae11a26fcf860e4b0c5eb6928b198bc57644 Mon Sep 17 00:00:00 2001
From: Tyler Treat <tyler.treat@apcera.com>
Date: Fri, 23 Jun 2017 10:03:01 -0500
Subject: [PATCH] Add reload count to server for monitoring

---
 server/monitor.go     |  2 ++
 server/reload.go      | 10 ++++++++--
 server/reload_test.go | 30 ++++++++++++++++++++++++++++++
 server/server.go      |  9 +++++++++
 4 files changed, 49 insertions(+), 2 deletions(-)

diff --git a/server/monitor.go b/server/monitor.go
index e76d86f4..7cc05977 100644
--- a/server/monitor.go
+++ b/server/monitor.go
@@ -399,6 +399,7 @@ type Varz struct {
 	SlowConsumers    int64             `json:"slow_consumers"`
 	Subscriptions    uint32            `json:"subscriptions"`
 	HTTPReqStats     map[string]uint64 `json:"http_req_stats"`
+	Reloaded         uint64            `json:"reloaded"`
 }
 
 func myUptime(d time.Duration) string {
@@ -478,6 +479,7 @@ func (s *Server) HandleVarz(w http.ResponseWriter, r *http.Request) {
 	v.OutBytes = atomic.LoadInt64(&s.outBytes)
 	v.SlowConsumers = atomic.LoadInt64(&s.slowConsumers)
 	v.Subscriptions = s.sl.Count()
+	v.Reloaded = s.reloaded
 	s.httpReqStats[VarzPath]++
 	// Need a copy here since s.httpReqStas can change while doing
 	// the marshaling down below.
diff --git a/server/reload.go b/server/reload.go
index c14da1c1..cfc3b8f2 100644
--- a/server/reload.go
+++ b/server/reload.go
@@ -249,14 +249,20 @@ func (s *Server) Reload() error {
 	if err != nil {
 		s.mu.Unlock()
 		// TODO: Dump previous good config to a .bak file?
-		return fmt.Errorf("Config reload failed: %s", err)
+		return err
 	}
 	s.mu.Unlock()
 
 	// Apply flags over config file settings.
 	newOpts = MergeOptions(newOpts, FlagSnapshot)
 	processOptions(newOpts)
-	return s.reloadOptions(newOpts)
+	err = s.reloadOptions(newOpts)
+	if err == nil {
+		s.mu.Lock()
+		s.reloaded++
+		s.mu.Unlock()
+	}
+	return err
 }
 
 // reloadOptions reloads the server config with the provided options. If an
diff --git a/server/reload_test.go b/server/reload_test.go
index 94c602ba..4b6c83a7 100644
--- a/server/reload_test.go
+++ b/server/reload_test.go
@@ -19,9 +19,15 @@ import (
 // not start with a config file.
 func TestConfigReloadNoConfigFile(t *testing.T) {
 	server := New(&Options{})
+	if reloaded := server.NumReloads(); reloaded != 0 {
+		t.Fatalf("Reloaded is incorrect.\nexpected: 0\ngot: %d", reloaded)
+	}
 	if server.Reload() == nil {
 		t.Fatal("Expected Reload to return an error")
 	}
+	if reloaded := server.NumReloads(); reloaded != 0 {
+		t.Fatalf("Reloaded is incorrect.\nexpected: 0\ngot: %d", reloaded)
+	}
 }
 
 // Ensure Reload returns an error when attempting to change an option which
@@ -30,6 +36,10 @@ func TestConfigReloadUnsupported(t *testing.T) {
 	server, opts, config := newServerWithSymlinkConfig(t, "tmp.conf", "./configs/reload/test.conf")
 	defer os.Remove(config)
 
+	if reloaded := server.NumReloads(); reloaded != 0 {
+		t.Fatalf("Reloaded is incorrect.\nexpected: 0\ngot: %d", reloaded)
+	}
+
 	golden := &Options{
 		ConfigFile:     config,
 		Host:           "0.0.0.0",
@@ -75,6 +85,10 @@ func TestConfigReloadUnsupported(t *testing.T) {
 		t.Fatalf("Options are incorrect.\nexpected: %+v\ngot: %+v",
 			golden, opts)
 	}
+
+	if reloaded := server.NumReloads(); reloaded != 0 {
+		t.Fatalf("Reloaded is incorrect.\nexpected: 0\ngot: %d", reloaded)
+	}
 }
 
 // Ensure Reload returns an error when reloading from a bad config file.
@@ -82,6 +96,10 @@ func TestConfigReloadInvalidConfig(t *testing.T) {
 	server, opts, config := newServerWithSymlinkConfig(t, "tmp.conf", "./configs/reload/test.conf")
 	defer os.Remove(config)
 
+	if reloaded := server.NumReloads(); reloaded != 0 {
+		t.Fatalf("Reloaded is incorrect.\nexpected: 0\ngot: %d", reloaded)
+	}
+
 	golden := &Options{
 		ConfigFile:     config,
 		Host:           "0.0.0.0",
@@ -127,6 +145,10 @@ func TestConfigReloadInvalidConfig(t *testing.T) {
 		t.Fatalf("Options are incorrect.\nexpected: %+v\ngot: %+v",
 			golden, opts)
 	}
+
+	if reloaded := server.NumReloads(); reloaded != 0 {
+		t.Fatalf("Reloaded is incorrect.\nexpected: 0\ngot: %d", reloaded)
+	}
 }
 
 // Ensure Reload returns nil and the config is changed on success.
@@ -134,6 +156,10 @@ func TestConfigReload(t *testing.T) {
 	server, opts, config := newServerWithSymlinkConfig(t, "tmp.conf", "./configs/reload/test.conf")
 	defer os.Remove(config)
 
+	if reloaded := server.NumReloads(); reloaded != 0 {
+		t.Fatalf("Reloaded is incorrect.\nexpected: 0\ngot: %d", reloaded)
+	}
+
 	golden := &Options{
 		ConfigFile:     config,
 		Host:           "0.0.0.0",
@@ -205,6 +231,10 @@ func TestConfigReload(t *testing.T) {
 	if !updated.Cluster.NoAdvertise {
 		t.Fatal("Expected NoAdvertise to be true")
 	}
+
+	if reloaded := server.NumReloads(); reloaded != 1 {
+		t.Fatalf("Reloaded is incorrect.\nexpected: 1\ngot: %d", reloaded)
+	}
 }
 
 // Ensure Reload supports TLS config changes. Test this by starting a server
diff --git a/server/server.go b/server/server.go
index cec881e3..eba6c327 100644
--- a/server/server.go
+++ b/server/server.go
@@ -79,6 +79,7 @@ type Server struct {
 	grRunning     bool
 	grWG          sync.WaitGroup // to wait on various go routines
 	cproto        int64          // number of clients supporting async INFO
+	reloaded      uint64         // number of times server config has been reloaded
 	logging       struct {
 		sync.RWMutex
 		logger Logger
@@ -918,6 +919,14 @@ func (s *Server) NumSubscriptions() uint32 {
 	return subs
 }
 
+// NumReloads returns the number of times the server config has been reloaded.
+func (s *Server) NumReloads() uint64 {
+	s.mu.Lock()
+	reloaded := s.reloaded
+	s.mu.Unlock()
+	return reloaded
+}
+
 // Addr will return the net.Addr object for the current listener.
 func (s *Server) Addr() net.Addr {
 	s.mu.Lock()