Use monotonic time for measuring time internally (#4154)

- [x] Branch rebased on top of current main (`git pull --rebase origin
main`)
- [x] Changes squashed to a single commit (described
[here](http://gitready.com/advanced/2009/02/10/squashing-commits-with-rebase.html))
 - [x] Build is green in Travis CI
- [x] You have certified that the contribution is your original work and
that you license the work to the project under the [Apache 2
license](https://github.com/nats-io/nats-server/blob/main/LICENSE)

server/accounts.go

@@ -3502,7 +3502,7 @@ func (s *Server) updateAccountClaimsWithRefresh(a *Account, ac *jwt.AccountClaim
 		a.jsLimits = nil
 	}
 
-	a.updated = time.Now().UTC()
+	a.updated = time.Now()
 	clients := a.getClientsLocked()
 	a.mu.Unlock()
 
@@ -3961,7 +3961,7 @@ func removeCb(s *Server, pubKey string) {
 	a.mpay = 0
 	a.mconns = 0
 	a.mleafs = 0
-	a.updated = time.Now().UTC()
+	a.updated = time.Now()
 	jsa := a.js
 	a.mu.Unlock()
 	// set the account to be expired and disconnect clients

server/gateway.go

@@ -761,7 +761,7 @@ func (s *Server) createGateway(cfg *gatewayCfg, url *url.URL, conn net.Conn) {
 	// Snapshot server options.
 	opts := s.getOpts()
 
-	now := time.Now().UTC()
+	now := time.Now()
 	c := &client{srv: s, nc: conn, start: now, last: now, kind: GATEWAY}
 
 	// Are we creating the gateway based on the configuration

server/monitor.go

@@ -783,7 +783,7 @@ type RouteInfo struct {
 // Routez returns a Routez struct containing information about routes.
 func (s *Server) Routez(routezOpts *RoutezOptions) (*Routez, error) {
 	rs := &Routez{Routes: []*RouteInfo{}}
-	rs.Now = time.Now().UTC()
+	rs.Now = time.Now()
 
 	if routezOpts == nil {
 		routezOpts = &RoutezOptions{}
@@ -970,7 +970,7 @@ func (s *Server) Subsz(opts *SubszOptions) (*Subsz, error) {
 	slStats := &SublistStats{}
 
 	// FIXME(dlc) - Make account aware.
-	sz := &Subsz{s.info.ID, time.Now().UTC(), slStats, 0, offset, limit, nil}
+	sz := &Subsz{s.info.ID, time.Now(), slStats, 0, offset, limit, nil}
 
 	if subdetail {
 		var raw [4096]*subscription
@@ -1595,7 +1595,7 @@ func (s *Server) updateVarzConfigReloadableFields(v *Varz) {
 	v.MaxPending = opts.MaxPending
 	v.TLSTimeout = opts.TLSTimeout
 	v.WriteDeadline = opts.WriteDeadline
-	v.ConfigLoadTime = s.configTime
+	v.ConfigLoadTime = s.configTime.UTC()
 	// Update route URLs if applicable
 	if s.varzUpdateRouteURLs {
 		v.Cluster.URLs = urlsToStrings(opts.Routes)

server/mqtt.go

@@ -422,7 +422,7 @@ func (s *Server) createMQTTClient(conn net.Conn, ws *websocket) *client {
 	if maxSubs == 0 {
 		maxSubs = -1
 	}
-	now := time.Now().UTC()
+	now := time.Now()
 
 	c := &client{srv: s, nc: conn, mpay: maxPay, msubs: maxSubs, start: now, last: now, mqtt: &mqtt{}, ws: ws}
 	c.headers = true

server/server.go

@@ -373,7 +373,7 @@ func NewServer(opts *Options) (*Server, error) {
 		info.TLSAvailable = true
 	}
 
-	now := time.Now().UTC()
+	now := time.Now()
 
 	s := &Server{
 		kp:                 kp,
@@ -884,7 +884,7 @@ func (s *Server) configureAccounts(reloading bool) (map[string]struct{}, error)
 			s.mu.Lock()
 			acc.mu.Lock()
 		}
-		acc.updated = time.Now().UTC()
+		acc.updated = time.Now()
 		acc.mu.Unlock()
 		return true
 	})
@@ -1383,7 +1383,7 @@ func (s *Server) createInternalClient(kind int) *client {
 	if kind != SYSTEM && kind != JETSTREAM && kind != ACCOUNT {
 		return nil
 	}
-	now := time.Now().UTC()
+	now := time.Now()
 	c := &client{srv: s, kind: kind, opts: internalOpts, msubs: -1, mpay: -1, start: now, last: now}
 	c.initClient()
 	c.echo = false
@@ -1453,7 +1453,7 @@ func (s *Server) registerAccountNoLock(acc *Account) *Account {
 		acc.lqws = make(map[string]int32)
 	}
 	acc.srv = s
-	acc.updated = time.Now().UTC()
+	acc.updated = time.Now()
 	accName := acc.Name
 	jsEnabled := len(acc.jsLimits) > 0
 	acc.mu.Unlock()
@@ -2581,7 +2581,7 @@ func (s *Server) createClient(conn net.Conn) *client {
 	if maxSubs == 0 {
 		maxSubs = -1
 	}
-	now := time.Now().UTC()
+	now := time.Now()
 
 	c := &client{srv: s, nc: conn, opts: defaultOpts, mpay: maxPay, msubs: maxSubs, start: now, last: now}
 
@@ -2748,7 +2748,7 @@ func (s *Server) createClient(conn net.Conn) *client {
 // This will save off a closed client in a ring buffer such that
 // /connz can inspect. Useful for debugging, etc.
 func (s *Server) saveClosedClient(c *client, nc net.Conn, reason ClosedState) {
-	now := time.Now().UTC()
+	now := time.Now()
 
 	s.accountDisconnectEvent(c, now, reason.String())