Dependent participants should not trigger count towards FirstJoinedAt (#3448)

* Dependent participants should not trigger count towards FirstJoinedAt

According to the API, empty timeout should be honored as long as no
independent participant joins the room. If we counted Agents and Egress
as part of FirstJoinedAt, it would have the side effect of using
departureTimeout instead of emptyTimeout for idle calculations.

* use Room logger

pkg/rtc/room.go

@@ -440,7 +440,7 @@ func (r *Room) Join(participant types.LocalParticipant, requestSource routing.Me
 		}
 	}
 
-	if r.FirstJoinedAt() == 0 {
+	if r.FirstJoinedAt() == 0 && !participant.IsDependent() {
 		r.joinedAt.Store(time.Now().Unix())
 	}
 
@@ -871,36 +871,42 @@ func (r *Room) IsClosed() bool {
 }
 
 // CloseIfEmpty closes the room if all participants had left, or it's still empty past timeout
-func (r *Room) CloseIfEmpty() {
+func (r *Room) CloseIfEmpty() string {
 	r.lock.Lock()
 
 	if r.IsClosed() || r.holds.Load() > 0 {
 		r.lock.Unlock()
-		return
+		return ""
 	}
 
 	for _, p := range r.participants {
 		if !p.IsDependent() {
 			r.lock.Unlock()
-			return
+			return ""
 		}
 	}
 
 	var timeout uint32
 	var elapsed int64
+	reason := ""
 	if r.FirstJoinedAt() > 0 && r.LastLeftAt() > 0 {
 		elapsed = time.Now().Unix() - r.LastLeftAt()
 		// need to give time in case participant is reconnecting
 		timeout = r.protoRoom.DepartureTimeout
+		reason = "departure timeout"
 	} else {
 		elapsed = time.Now().Unix() - r.protoRoom.CreationTime
 		timeout = r.protoRoom.EmptyTimeout
+		reason = "empty timeout"
 	}
 	r.lock.Unlock()
 
 	if elapsed >= int64(timeout) {
 		r.Close(types.ParticipantCloseReasonRoomClosed)
+		return reason
 	}
+
+	return ""
 }
 
 func (r *Room) Close(reason types.ParticipantCloseReason) {

pkg/service/roommanager.go

@@ -197,7 +197,10 @@ func (r *RoomManager) CloseIdleRooms() {
 	r.lock.RUnlock()
 
 	for _, room := range rooms {
-		room.CloseIfEmpty()
+		reason := room.CloseIfEmpty()
+		if reason != "" {
+			room.Logger.Infow("closing idle room", "reason", reason)
+		}
 	}
 }