Add "server status" command

Right now, it prints the number of active users and number of
downstream connections.

doc/soju.1.scd

@@ -320,6 +320,9 @@ abbreviated form, for instance *network* can be abbreviated as *net* or just
 *user delete* <username>
 	Delete a soju user. Only admins can delete accounts.
 
+*server status*
+	Show some bouncer statistics. Only admins can query this information.
+
 # AUTHORS
 
 Maintained by Simon Ser <contact@emersion.fr>, who is assisted by other

server.go

@@ -55,8 +55,9 @@ type Server struct {
 	AcceptProxyIPs config.IPSet
 	Identd         *Identd // can be nil
 
-	db     Database
-	stopWG sync.WaitGroup
+	db        Database
+	stopWG    sync.WaitGroup
+	connCount int64 // atomic
 
 	lock      sync.Mutex
 	listeners map[net.Listener]struct{}
@@ -165,6 +166,7 @@ func (s *Server) addUserLocked(user *User) *user {
 var lastDownstreamID uint64 = 0
 
 func (s *Server) handle(ic ircConn) {
+	atomic.AddInt64(&s.connCount, 1)
 	id := atomic.AddUint64(&lastDownstreamID, 1)
 	dc := newDownstreamConn(s, ic, id)
 	if err := dc.runUntilRegistered(); err != nil {
@@ -177,6 +179,7 @@ func (s *Server) handle(ic ircConn) {
 		dc.user.events <- eventDownstreamDisconnected{dc}
 	}
 	dc.Close()
+	atomic.AddInt64(&s.connCount, -1)
 }
 
 func (s *Server) Serve(ln net.Listener) error {
@@ -249,3 +252,17 @@ func parseForwarded(h http.Header) map[string]string {
 	_, params, _ := mime.ParseMediaType("hack; " + forwarded)
 	return params
 }
+
+type ServerStats struct {
+	Users       int
+	Downstreams int64
+}
+
+func (s *Server) Stats() *ServerStats {
+	var stats ServerStats
+	s.lock.Lock()
+	stats.Users = len(s.users)
+	s.lock.Unlock()
+	stats.Downstreams = atomic.LoadInt64(&s.connCount)
+	return &stats
+}

service.go

@@ -292,6 +292,16 @@ func init() {
 				},
 			},
 		},
+		"server": {
+			children: serviceCommandSet{
+				"status": {
+					desc:   "show server statistics",
+					handle: handleServiceServerStatus,
+					admin:  true,
+				},
+			},
+			admin: true,
+		},
 	}
 }
 
@@ -1007,3 +1017,9 @@ func handleServiceChannelUpdate(dc *downstreamConn, params []string) error {
 	sendServicePRIVMSG(dc, fmt.Sprintf("updated channel %q", name))
 	return nil
 }
+
+func handleServiceServerStatus(dc *downstreamConn, params []string) error {
+	stats := dc.user.srv.Stats()
+	sendServicePRIVMSG(dc, fmt.Sprintf("%v users, %v downstreams", stats.Users, stats.Downstreams))
+	return nil
+}