From 02c649d97e12fcc0723afefa6ea69a3147772def Mon Sep 17 00:00:00 2001
From: Eli Mallon <eli@iame.li>
Date: Wed, 10 Jun 2026 14:39:07 -0700
Subject: [PATCH] viewers: count WHEP sessions only once connected
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

WebRTCPlayback2 incremented the viewer count as soon as the SDP
answer was minted, so handshakes that never established — the web
player churns through several peer connections while loading or
before falling back to HLS — each counted as a viewer until ICE
failure detection fired seconds later. That's the "count jumps +4-5
then settles" spike. Count on PeerConnectionStateConnected instead,
with the increment/decrement paired under a mutex so a connect racing
teardown can't leak a count.

Also point ViewerDec's per-protocol branch at ViewersTotal — it was
updating/deleting the per-streamer gauge with a protocol label.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
---
 pkg/media/webrtc_playback2.go | 36 ++++++++++++++++++++++++++++++++---
 pkg/spmetrics/spmetrics.go    |  4 ++--
 2 files changed, 35 insertions(+), 5 deletions(-)

diff --git a/pkg/media/webrtc_playback2.go b/pkg/media/webrtc_playback2.go
index 1bbc1b71..b17a217e 100644
--- a/pkg/media/webrtc_playback2.go
+++ b/pkg/media/webrtc_playback2.go
@@ -3,6 +3,7 @@ package media
 import (
 	"context"
 	"fmt"
+	"sync"
 	"time"
 
 	"github.com/google/uuid"
@@ -83,9 +84,37 @@ func (mm *MediaManager) WebRTCPlayback2(ctx context.Context, user string, rendit
 
 	// Setup complete! Now we boot up streaming in the background while returning the SDP offer to the user.
 
+	// The session only counts as a viewer once the peer connection actually
+	// establishes — counting at SDP-answer time inflated the count with
+	// handshakes that never connected (each lingering until ICE failure
+	// detection). The mutex pairs the increment with exactly one decrement
+	// even if a connect races session teardown.
+	var viewerMu sync.Mutex
+	viewerCounted := false
+	viewerDone := false
+	markConnected := func() {
+		viewerMu.Lock()
+		defer viewerMu.Unlock()
+		if viewerDone || viewerCounted {
+			return
+		}
+		viewerCounted = true
+		mm.IncrementViewerCount(user, "webrtc")
+	}
+	markDone := func() {
+		viewerMu.Lock()
+		defer viewerMu.Unlock()
+		viewerDone = true
+		if viewerCounted {
+			viewerCounted = false
+			mm.DecrementViewerCount(user, "webrtc")
+		}
+	}
+
 	go func() {
 		ctx, cancel := context.WithCancel(ctx)
 		defer cancel()
+		defer markDone()
 
 		latency := time.Duration(0)
 
@@ -194,9 +223,6 @@ func (mm *MediaManager) WebRTCPlayback2(ctx context.Context, user string, rendit
 			}
 		}()
 
-		mm.IncrementViewerCount(user, "webrtc")
-		defer mm.DecrementViewerCount(user, "webrtc")
-
 		if !audioOnly {
 			go func() {
 				rtcpBuf := make([]byte, 1500)
@@ -228,6 +254,10 @@ func (mm *MediaManager) WebRTCPlayback2(ctx context.Context, user string, rendit
 		peerConnection.OnConnectionStateChange(func(s webrtc.PeerConnectionState) {
 			log.Log(ctx, "Peer Connection State has changed", "state", s.String())
 
+			if s == webrtc.PeerConnectionStateConnected {
+				markConnected()
+			}
+
 			if s == webrtc.PeerConnectionStateFailed || s == webrtc.PeerConnectionStateClosed || s == webrtc.PeerConnectionStateDisconnected {
 				// Wait until PeerConnection has had no network activity for 30 seconds or another failure. It may be reconnected using an ICE Restart.
 				// Use webrtc.PeerConnectionStateDisconnected if you are interested in detecting faster timeout.
diff --git a/pkg/spmetrics/spmetrics.go b/pkg/spmetrics/spmetrics.go
index 9c25f351..b62673ba 100644
--- a/pkg/spmetrics/spmetrics.go
+++ b/pkg/spmetrics/spmetrics.go
@@ -237,9 +237,9 @@ func ViewerDec(user string, protocol string) {
 		}
 		viewersByProtocol[protocol]--
 		if viewersByProtocol[protocol] == 0 {
-			Viewers.DeleteLabelValues(protocol)
+			ViewersTotal.DeleteLabelValues(protocol)
 		} else {
-			Viewers.WithLabelValues(protocol).Set(float64(viewersByProtocol[protocol]))
+			ViewersTotal.WithLabelValues(protocol).Set(float64(viewersByProtocol[protocol]))
 		}
 	}()
 }
-- 
2.51.2