From 1c69a9eeed240024d43baf66649498cfc7217fc3 Mon Sep 17 00:00:00 2001
From: David Zhao <dz@livekit.io>
Date: Wed, 19 Feb 2025 22:57:40 -0800
Subject: [PATCH] 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            | 14 ++++++++++----
 pkg/service/roommanager.go |  5 ++++-
 2 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/pkg/rtc/room.go b/pkg/rtc/room.go
index a2fa0381d..5f7a2ea4a 100644
--- a/pkg/rtc/room.go
+++ b/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) {
diff --git a/pkg/service/roommanager.go b/pkg/service/roommanager.go
index 2417f1f66..18835af28 100644
--- a/pkg/service/roommanager.go
+++ b/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)
+		}
 	}
 }