[RSDK-8293] Pass in Connection to Answerer in WebRTC Server

rpc/dial_options.go

@@ -64,6 +64,9 @@ type dialOptions struct {
 	// interceptors
 	unaryInterceptor  grpc.UnaryClientInterceptor
 	streamInterceptor grpc.StreamClientInterceptor
+
+	// conn can be used to force the webrtcSignalingAnswerer to use a preexisting connection instead of dialing and managing its own.
+	externalSignalerConn ClientConn
 }
 
 // DialMulticastDNSOptions dictate any special settings to apply while dialing via mDNS.
@@ -280,3 +283,10 @@ func WithForceDirectGRPC() DialOption {
 		o.disableDirect = false
 	})
 }
+
+// WithConn provides a preexisting connection to use. This option forces the webrtcSignalingAnswerer to not dial or manage a connection.
+func WithConn(externalSignalerConn ClientConn) DialOption {
+	return newFuncDialOption(func(o *dialOptions) {
+		o.externalSignalerConn = externalSignalerConn
+	})
+}

rpc/wrtc_signaling_answerer.go

@@ -40,8 +40,9 @@ type webrtcSignalingAnswerer struct {
 	// conn is used to share the direct gRPC connection used by the answerer workers. As direct gRPC connections
 	// reconnect on their own, custom reconnect logic is not needed. However, keepalives are necessary for the connection
 	// to realize it's been disconnected quickly and start reconnecting.
-	connMu sync.Mutex
-	conn   ClientConn
+	connMu     sync.Mutex
+	conn       ClientConn
+	sharedConn bool
 
 	logger utils.ZapCompatibleLogger
 }
@@ -61,8 +62,12 @@ func newWebRTCSignalingAnswerer(
 	dialOptsCopy := make([]DialOption, len(dialOpts))
 	copy(dialOptsCopy, dialOpts)
 	dialOptsCopy = append(dialOptsCopy, WithWebRTCOptions(DialWebRTCOptions{Disable: true}))
+	options := &dialOptions{}
+	for _, opt := range dialOptsCopy {
+		opt.apply(options)
+	}
 	bgWorkers := utils.NewBackgroundStoppableWorkers()
-	return &webrtcSignalingAnswerer{
+	ans := &webrtcSignalingAnswerer{
 		address:      address,
 		hosts:        hosts,
 		server:       server,
@@ -71,6 +76,11 @@ func newWebRTCSignalingAnswerer(
 		bgWorkers:    bgWorkers,
 		logger:       logger,
 	}
+	if options.conn != nil {
+		ans.conn = options.conn
+		ans.sharedConn = true
+	}
+	return ans
 }
 
 const (
@@ -260,9 +270,11 @@ func (ans *webrtcSignalingAnswerer) Stop() {
 	ans.connMu.Lock()
 	defer ans.connMu.Unlock()
 	if ans.conn != nil {
-		err := ans.conn.Close()
-		if isNetworkError(err) {
-			ans.logger.Errorw("error closing signaling connection", "error", err)
+		if !ans.sharedConn {
+			err := ans.conn.Close()
+			if isNetworkError(err) {
+				ans.logger.Errorw("error closing signaling connection", "error", err)
+			}
 		}
 		ans.conn = nil
 	}