WebSocket Server Garbage Collected

[murat-dogan]

https://github.com/murat-dogan/node-datachannel/blob/websocket-examples/examples/client-server/signaling-server.js

In this example after 1 client connection, the garbage collector deletes wsServer.

Workaround; https://github.com/murat-dogan/node-datachannel/blob/c311c111bdd1b3c20d056f6f46a7c3c12610f8ce/examples/client-server/signaling-server.js#L40-L44

Here is the log

murat@murat-ThinkBook:~/js/node-datachannel/examples/client-server$ node --trace-gc signaling-server.js 
2024-07-05 16:49:33.016 DEBUG [612304] [WebSocketServerWrapper::WebSocketServerWrapper@38] Constructor called
2024-07-05 16:49:33.016 DEBUG [612304] [WebSocketServerWrapper::WebSocketServerWrapper@157] Creating a new WebSocketServer
2024-07-05 16:49:33.016 DEBUG [612304] [rtc::impl::Init::doInit@113] Global initialization
2024-07-05 16:49:33.016 DEBUG [612304] [rtc::impl::Init::doInit@123] Spawning 8 threads
2024-07-05 16:49:33.016 DEBUG [612323] [rtc::impl::PollService::runLoop@164] Poll service started
2024-07-05 16:49:33.021 DEBUG [612304] [rtc::impl::TcpServer::TcpServer@25] Initializing TCP server
2024-07-05 16:49:33.021 DEBUG [612304] [rtc::impl::TcpServer::listen@97] Listening on port 8000
2024-07-05 16:49:33.021 DEBUG [612304] [WebSocketServerWrapper::WebSocketServerWrapper@166] WebSocketServer created
2024-07-05 16:49:33.021 DEBUG [612304] [WebSocketServerWrapper::onClient@227] onClient() called
2024-07-05 16:49:33.021 INFO  [612326] [rtc::impl::WebSocketServer::runLoop@72] Starting WebSocketServer
2024-07-05 16:49:38.794 DEBUG [612326] [rtc::impl::TcpTransport::TcpTransport@63] Initializing TCP transport with socket
2024-07-05 16:49:38.794 DEBUG [612326] [rtc::impl::WsTransport::WsTransport@61] Initializing WebSocket transport
2024-07-05 16:49:38.794 DEBUG [612326] [WebSocketServerWrapper::onClient@248] onClient ws received from WebSocketServer
2024-07-05 16:49:38.795 DEBUG [612304] [WebSocketServerWrapper::onClient@251] mOnClientCallback call(1)
2024-07-05 16:49:38.795 DEBUG [612323] [rtc::impl::WsHandshake::parseHttpRequest@152] WebSocket request method="GET", path="/mm2X"
2024-07-05 16:49:38.795 DEBUG [612304] [WebSocketWrapper::WebSocketWrapper@59] Constructor called
2024-07-05 16:49:38.795 DEBUG [612304] [WebSocketWrapper::WebSocketWrapper@66] Using WebSocket got from WebSocketServer
2024-07-05 16:49:38.795 INFO  [612323] [rtc::impl::WsTransport::incoming@135] WebSocket server-side open
2024-07-05 16:49:38.795 DEBUG [612323] [rtc::impl::WsTransport::sendHttpResponse@209] Sending WebSocket HTTP response
2024-07-05 16:49:38.795 DEBUG [612304] [WebSocketServerWrapper::onClient@262] mOnClientCallback call(2)
2024-07-05 16:49:38.795 DEBUG [612323] [rtc::impl::WebSocket::initWsTransport@428] WebSocket open
2024-07-05 16:49:38.896 DEBUG [612304] [WebSocketWrapper::path@508] path() called
New Connection from mm2X
2024-07-05 16:49:38.913 DEBUG [612304] [WebSocketWrapper::onMessage@722] onMessage() called
2024-07-05 16:49:38.913 DEBUG [612304] [WebSocketWrapper::onMessage@741] setting onMessage cb on mWebSocketPtr
2024-07-05 16:49:38.913 DEBUG [612304] [WebSocketWrapper::onClosed@609] onClosed() called
2024-07-05 16:49:38.913 DEBUG [612304] [WebSocketWrapper::onError@646] onError() called
2024-07-05 16:49:48.804 DEBUG [612323] [rtc::impl::WsTransport::recvFrame@302] WebSocket received frame: opcode=9, length=4
2024-07-05 16:49:48.804 DEBUG [612323] [rtc::impl::WsTransport::recvFrame@349] WebSocket received ping, sending pong
2024-07-05 16:49:48.804 DEBUG [612323] [rtc::impl::WsTransport::sendFrame@375] WebSocket sending frame: opcode=10, length=4
[612304:0x70a8cc0]    22192 ms: Mark-Compact (reduce) 4.3 (4.7) -> 3.2 (4.7) MB, 3.63 / 0.03 ms  (+ 2.5 ms in 11 steps since start of marking, biggest step 0.3 ms, walltime since start of marking 7 ms) (average mu = 1.000, current mu = 1.000) finalize incremental marking via task; GC in old space requested
2024-07-05 16:49:55.135 DEBUG [612304] [WebSocketServerWrapper::~WebSocketServerWrapper@172] Destructor called
2024-07-05 16:49:55.135 DEBUG [612304] [WebSocketServerWrapper::doStop@178] doStop() called
2024-07-05 16:49:55.135 DEBUG [612304] [WebSocketServerWrapper::doStop@181] Stopping...
2024-07-05 16:49:55.135 DEBUG [612304] [rtc::impl::WebSocketServer::stop@65] Stopping WebSocketServer thread
2024-07-05 16:49:55.135 DEBUG [612304] [rtc::impl::TcpServer::close@89] Closing TCP server socket
2024-07-05 16:49:55.135 DEBUG [612326] [rtc::impl::TcpServer::accept@82] TCP server closed
2024-07-05 16:49:55.135 INFO  [612326] [rtc::impl::WebSocketServer::runLoop@97] Stopped WebSocketServer

@ptesavol Could you please also check?

[paullouisageneau]

All objects in the wrapper behave like that currently, as soon as they are not reachable anymore they can be garbage collected (even for globals), so you have to keep a reachable reference. Maybe it could be changed.

[murat-dogan]

If I write only 1 line like this

let wsServer = new nodeDataChannel.WebSocketServer({ bindAddress: '127.0.0.1', port: 8000 });

It will be directly deleted by the garbage collector, this is normal. No reference, callback etc.

If I write this line

let peer1 = new nodeDataChannel.PeerConnection('Peer1', { iceServers: ['stun:stun.l.google.com:19302'] });

It will not be deleted by the garbage collector, because we have a callback created here https://github.com/murat-dogan/node-datachannel/blob/63ec3215063931aae772f2acfa2c2199bfeca2b3/src/peer-connection-wrapper.cpp#L252

Here I am setting a callback. Like this

const wsServer = new nodeDataChannel.WebSocketServer({ bindAddress: '127.0.0.1', port: 8000 });

wsServer.onClient((ws) => {
....
}

And it is not garbage collected(because we have a callback), until a client is connected. When a client connects, it is being deleted. I don't see any difference on the binding side.

Do you have any idea?

[Msfrhdsa]

Hopefully this will be fixed soon. Workaround is an eyesore.