Address review comments.

Author: sbruens

Diff for: cmd/outline-ss-server/main.go

@@ -161,7 +161,7 @@ func (s *SSServer) runConfig(config Config) (func(), error) {
 			manager:   s.lnManager,
 			listeners: make(map[string]service.Listener),
 		}
-		defer lnSet.Close()
+		defer lnSet.Close() // This closes all the listeners in the set.
 
 		startErrCh <- func() error {
 			portCiphers := make(map[int]*list.List) // Values are *List of *CipherEntry.

Diff for: cmd/outline-ss-server/metrics.go

@@ -38,7 +38,7 @@ type outlineMetrics struct {
 
 	buildInfo            *prometheus.GaugeVec
 	accessKeys           prometheus.Gauge
-	listeners            prometheus.Gauge
+	ports                prometheus.Gauge
 	dataBytes            *prometheus.CounterVec
 	dataBytesPerLocation *prometheus.CounterVec
 	timeToCipherMs       *prometheus.HistogramVec
@@ -183,10 +183,10 @@ func newPrometheusOutlineMetrics(ip2info ipinfo.IPInfoMap, registerer prometheus
 			Name:      "keys",
 			Help:      "Count of access keys",
 		}),
-		listeners: prometheus.NewGauge(prometheus.GaugeOpts{
+		ports: prometheus.NewGauge(prometheus.GaugeOpts{
 			Namespace: namespace,
-			Name:      "listeners",
-			Help:      "Count of open Shadowsocks listeners",
+			Name:      "ports",
+			Help:      "Count of open Shadowsocks ports",
 		}),
 		tcpProbes: prometheus.NewHistogramVec(prometheus.HistogramOpts{
 			Namespace: namespace,
@@ -265,7 +265,7 @@ func newPrometheusOutlineMetrics(ip2info ipinfo.IPInfoMap, registerer prometheus
 	m.tunnelTimeCollector = newTunnelTimeCollector(ip2info, registerer)
 
 	// TODO: Is it possible to pass where to register the collectors?
-	registerer.MustRegister(m.buildInfo, m.accessKeys, m.listeners, m.tcpProbes, m.tcpOpenConnections, m.tcpClosedConnections, m.tcpConnectionDurationMs,
+	registerer.MustRegister(m.buildInfo, m.accessKeys, m.ports, m.tcpProbes, m.tcpOpenConnections, m.tcpClosedConnections, m.tcpConnectionDurationMs,
 		m.dataBytes, m.dataBytesPerLocation, m.timeToCipherMs, m.udpPacketsFromClientPerLocation, m.udpAddedNatEntries, m.udpRemovedNatEntries,
 		m.tunnelTimeCollector)
 	return m
@@ -275,9 +275,9 @@ func (m *outlineMetrics) SetBuildInfo(version string) {
 	m.buildInfo.WithLabelValues(version).Set(1)
 }
 
-func (m *outlineMetrics) SetNumAccessKeys(numKeys int, listeners int) {
+func (m *outlineMetrics) SetNumAccessKeys(numKeys int, ports int) {
 	m.accessKeys.Set(float64(numKeys))
-	m.listeners.Set(float64(listeners))
+	m.ports.Set(float64(ports))
 }
 
 func (m *outlineMetrics) AddOpenTCPConnection(clientInfo ipinfo.IPInfo) {

Diff for: service/listeners.go

@@ -46,9 +46,7 @@ type acceptResponse struct {
 }
 
 type sharedListener struct {
-	listener net.TCPListener
-	once     sync.Once
-
+	listener    net.TCPListener
 	acceptCh    *atomic.Value // closed by first Close() call
 	closeCh     chan struct{}
 	onCloseFunc func() error
@@ -71,12 +69,8 @@ func (sl *sharedListener) AcceptStream() (transport.StreamConn, error) {
 // Only when the last user closes it, we actually close it.
 func (sl *sharedListener) Close() error {
 	sl.acceptCh = nil
-	var err error
-	sl.once.Do(func() {
-		close(sl.closeCh)
-		err = sl.onCloseFunc()
-	})
-	return err
+	close(sl.closeCh)
+	return sl.onCloseFunc()
 }
 
 func (sl *sharedListener) Addr() net.Addr {
@@ -85,16 +79,11 @@ func (sl *sharedListener) Addr() net.Addr {
 
 type sharedPacketConn struct {
 	net.PacketConn
-	once        sync.Once
 	onCloseFunc func() error
 }
 
 func (spc *sharedPacketConn) Close() error {
-	var err error
-	spc.once.Do(func() {
-		err = spc.onCloseFunc()
-	})
-	return err
+	return spc.onCloseFunc()
 }
 
 type concreteListener struct {