Add basic stats API.

Can be used to query number of sessions, rooms and (if Janus is configured),
overall MCU clients and publishers.

server.conf.in

@@ -110,3 +110,8 @@ url =
 # information.
 # Leave empty to disable GeoIP lookups.
 #license =
+
+[stats]
+# Comma-separated list of IP addresses that are allowed to access the stats
+# endpoint. Leave empty (or commented) to only allow access from "127.0.0.1".
+#allowed_ips =

src/signaling/backend_server.go

@@ -30,6 +30,7 @@ import (
 	"io"
 	"io/ioutil"
 	"log"
+	"net"
 	"net/http"
 	"reflect"
 	"strings"
@@ -49,6 +50,7 @@ const (
 )
 
 type BackendServer struct {
+	hub          *Hub
 	nats         NatsClient
 	roomSessions RoomSessions
 
@@ -61,6 +63,8 @@ type BackendServer struct {
 	turnsecret  []byte
 	turnvalid   time.Duration
 	turnservers []string
+
+	statsAllowedIps map[string]bool
 }
 
 func NewBackendServer(config *goconf.ConfigFile, hub *Hub, version string) (*BackendServer, error) {
@@ -95,7 +99,26 @@ func NewBackendServer(config *goconf.ConfigFile, hub *Hub, version string) (*Bac
 		}
 	}
 
+	statsAllowed, _ := config.GetString("stats", "allowed_ips")
+	var statsAllowedIps map[string]bool
+	if statsAllowed == "" {
+		log.Printf("No IPs configured for the stats endpoint, only allowing access from 127.0.0.1")
+		statsAllowedIps = map[string]bool{
+			"127.0.0.1": true,
+		}
+	} else {
+		log.Printf("Only allowing access to the stats endpoing from %s", statsAllowed)
+		statsAllowedIps = make(map[string]bool)
+		for _, ip := range strings.Split(statsAllowed, ",") {
+			ip = strings.TrimSpace(ip)
+			if ip != "" {
+				statsAllowedIps[ip] = true
+			}
+		}
+	}
+
 	return &BackendServer{
+		hub:          hub,
 		nats:         hub.nats,
 		roomSessions: hub.roomSessions,
 		version:      version,
@@ -107,6 +130,8 @@ func NewBackendServer(config *goconf.ConfigFile, hub *Hub, version string) (*Bac
 		turnsecret:  []byte(turnsecret),
 		turnvalid:   turnvalid,
 		turnservers: turnserverslist,
+
+		statsAllowedIps: statsAllowedIps,
 	}, nil
 }
 
@@ -124,6 +149,7 @@ func (b *BackendServer) Start(r *mux.Router) error {
 	s := r.PathPrefix("/api/v1").Subrouter()
 	s.HandleFunc("/welcome", b.setComonHeaders(b.welcomeFunc)).Methods("GET")
 	s.HandleFunc("/room/{roomid}", b.setComonHeaders(b.validateBackendRequest(b.roomHandler))).Methods("POST")
+	s.HandleFunc("/stats", b.setComonHeaders(b.validateStatsRequest(b.statsHandler))).Methods("GET")
 
 	// Provide a REST service to get TURN credentials.
 	// See https://tools.ietf.org/html/draft-uberti-behave-turn-rest-00
@@ -524,3 +550,35 @@ func (b *BackendServer) roomHandler(w http.ResponseWriter, r *http.Request, body
 	// TODO(jojo): Return better response struct.
 	w.Write([]byte("{}"))
 }
+
+func (b *BackendServer) validateStatsRequest(f func(http.ResponseWriter, *http.Request)) func(http.ResponseWriter, *http.Request) {
+	return func(w http.ResponseWriter, r *http.Request) {
+		addr := getRealUserIP(r)
+		if strings.Contains(addr, ":") {
+			if host, _, err := net.SplitHostPort(addr); err == nil {
+				addr = host
+			}
+		}
+		if !b.statsAllowedIps[addr] {
+			http.Error(w, "Authentication check failed", http.StatusForbidden)
+			return
+		}
+
+		f(w, r)
+	}
+}
+
+func (b *BackendServer) statsHandler(w http.ResponseWriter, r *http.Request) {
+	stats := b.hub.GetStats()
+	statsData, err := json.MarshalIndent(stats, "", "  ")
+	if err != nil {
+		log.Printf("Could not serialize stats %+v: %s", stats, err)
+		http.Error(w, "Internal server error", http.StatusInternalServerError)
+		return
+	}
+
+	w.Header().Set("Content-Type", "application/json; charset=utf-8")
+	w.Header().Set("X-Content-Type-Options", "nosniff")
+	w.WriteHeader(http.StatusOK)
+	w.Write(statsData)
+}

src/signaling/hub.go

@@ -1413,6 +1413,22 @@ func (h *Hub) processRoomParticipants(message *BackendServerRoomRequest) {
 	room.PublishUsersChanged(message.Participants.Changed, message.Participants.Users)
 }
 
+func (h *Hub) GetStats() map[string]interface{} {
+	result := make(map[string]interface{})
+	h.ru.RLock()
+	result["rooms"] = len(h.rooms)
+	h.ru.RUnlock()
+	h.mu.Lock()
+	result["sessions"] = len(h.sessions)
+	h.mu.Unlock()
+	if h.mcu != nil {
+		if stats := h.mcu.GetStats(); stats != nil {
+			result["mcu"] = stats
+		}
+	}
+	return result
+}
+
 func getRealUserIP(r *http.Request) string {
 	// Note this function assumes it is running behind a trusted proxy, so
 	// the headers can be trusted.

src/signaling/mcu_common.go

@@ -45,6 +45,8 @@ type Mcu interface {
 	Start() error
 	Stop()
 
+	GetStats() interface{}
+
 	NewPublisher(ctx context.Context, listener McuListener, id string, streamType string) (McuPublisher, error)
 	NewSubscriber(ctx context.Context, listener McuListener, publisher string, streamType string) (McuSubscriber, error)
 }

src/signaling/mcu_janus.go

@@ -159,6 +159,8 @@ type mcuJanus struct {
 
 	reconnectTimer    *time.Timer
 	reconnectInterval time.Duration
+
+	connectedSince time.Time
 }
 
 func NewMcuJanus(url string, config *goconf.ConfigFile, nats NatsClient) (Mcu, error) {
@@ -303,6 +305,7 @@ func (m *mcuJanus) Start() error {
 		return err
 	}
 	log.Println("Created Janus session", m.session.Id)
+	m.connectedSince = time.Now()
 
 	if m.handle, err = m.session.Attach(ctx, pluginVideoRoom); err != nil {
 		m.disconnect()
@@ -346,6 +349,31 @@ func (m *mcuJanus) Stop() {
 	m.reconnectTimer.Stop()
 }
 
+type mcuJanusConnectionStats struct {
+	Url        string     `json:"url"`
+	Connected  bool       `json:"connected"`
+	Publishers int64      `json:"publishers"`
+	Clients    int64      `json:"clients"`
+	Uptime     *time.Time `json:"uptime,omitempty"`
+}
+
+func (m *mcuJanus) GetStats() interface{} {
+	result := mcuJanusConnectionStats{
+		Url: m.url,
+	}
+	if m.session != nil {
+		result.Connected = true
+		result.Uptime = &m.connectedSince
+	}
+	m.mu.Lock()
+	result.Publishers = int64(len(m.publisherRoomIds))
+	m.mu.Unlock()
+	m.muClients.Lock()
+	result.Clients = int64(len(m.clients))
+	m.muClients.Unlock()
+	return result
+}
+
 func (m *mcuJanus) sendKeepalive() {
 	ctx := context.TODO()
 	if _, err := m.session.KeepAlive(ctx); err != nil {

src/signaling/mcu_test.go

@@ -41,6 +41,10 @@ func (m *TestMCU) Start() error {
 func (m *TestMCU) Stop() {
 }
 
+func (m *TestMCU) GetStats() interface{} {
+	return nil
+}
+
 func (m *TestMCU) NewPublisher(ctx context.Context, listener McuListener, id string, streamType string) (McuPublisher, error) {
 	return nil, fmt.Errorf("Not implemented")
 }