Websocket S2S: ping every 55s to keep alive.

CHANGELOG.md

@@ -14,9 +14,11 @@ TODO?: mod_s2s_peertubelivechat: dont allow to connect to remote server that are
 TODO: when sanitizing remote chat endpoint, check that the domain is the same as the video domain (or is room.videodomain.tld).
 TODO: only compatible with Prosody 0.12.x. So it should be documented for people using «system Prosody». And i should fix the ARM AppImage.
 TODO: it seems that in some case A->B can be Websocket, and B->A direct S2S. Check if this is fine. And maybe we can optimise some code, by allowing directS2S event if current server dont accept it.
-TODO: check that the keepalive is working with websocket s2s. It seems the connection is often close and reopened.
+TODO: add a specific websocket timeout option, and send keepalive. In production the connection is often close and reopened because of nginx 30s timeout.
 TODO: alpha.2 version force Websocket S2S when available, even if s2s is possible. Revert this before releasing.
 TODO?: always generate self-signed certificates. Could be used for outgoing s2s?
+TODO: check in the diagnostic tool that Prosody is >=0.12
+TODO: ARM AppImage, and to say that needs Prosody >=0.12
 
 ### Minor changes and fixes
 

prosody-modules/mod_websocket_s2s_peertubelivechat/mod_websocket_s2s_peertubelivechat.lua

@@ -35,6 +35,7 @@ local frame_buffer_limit = module:get_option_number("websocket_frame_buffer_limi
 local frame_fragment_limit = module:get_option_number("websocket_frame_fragment_limit", 8);
 local stream_close_timeout = module:get_option_number("s2s_close_timeout", 5);
 local consider_websocket_secure = module:get_option_boolean("consider_websocket_secure");
+local websocket_s2s_ping_interval = module:get_option_number("websocket_s2s_ping_interval", 55);
 
 local xmlns_framing = "urn:ietf:params:xml:ns:xmpp-framing-server";
 local xmlns_streams = "http://etherx.jabber.org/streams";
@@ -366,7 +367,7 @@ local function keepalive(event)
 	local session = event.session;
 	if session.open_stream == session_open_stream then
 		local log = session.log or log
-		log("debug", "Sending a keepalive on outgoint websocket s2s");
+		log("debug", "Sending a keepalive on outgoing websocket s2s");
 		return session.conn:write(build_frame({ opcode = 0x9, FIN = true }));
 	end
 end
@@ -594,6 +595,14 @@ function route_to_new_session(event)
 		conn:setlistener(s2s_listener);
 		s2s_listener.register_outgoing(conn, session);
 		s2s_listener.onconnect(conn);
+
+		-- many websocket server or proxy have timeouts when the connection is not active.
+		-- for example when nginx proxifies websocket, it has a default 60 seconds timeout.
+		-- so we will send keepalives on outgoing connections (in addition to keepalives sent by mod_s2s).
+		session.ws_s2s_keepalive_timer = module:add_timer(websocket_s2s_ping_interval, function ()
+			log("debug", "Timer triggered, sending a keepalive on outgoing websocket s2s");
+			return session.conn:write(build_frame({ opcode = 0x9, FIN = true }));
+		end);
 	end
 
 	local function onclose(s, code, message)
@@ -657,6 +666,17 @@ function module.add_host(module)
 	});
 
 	module:hook("s2s-read-timeout", keepalive, -0.9);
+	module:hook("s2s-destroyed", function (event)
+		local session = event.session;
+		if not session then
+			return;
+		end
+		local log = session.log or log;
+		if session.ws_s2s_keepalive_timer then
+			log("debug", "Stopping keepalive timer");
+			session.ws_s2s_keepalive_timer:stop();
+		end
+	end);
 end
 
 if require"core.modulemanager".get_modules_for_host("*"):contains(module.name) then

server/lib/prosody/config/content.ts

@@ -296,6 +296,9 @@ class ProsodyConfigContent {
     this.global.set('peertubelivechat_instance_url', publicServerUrl)
 
     this.global.add('modules_enabled', 'websocket_s2s_peertubelivechat')
+    // Nginx closes the websockets connection after a timeout. Seems the default is 60s.
+    // So we will ping on outgoing websocket s2s connection every 55s.
+    this.global.set('websocket_s2s_ping_interval', 55)
     // FIXME: seems to be necessary to add the module on the muc host, so that dialback can trigger route/remote.
     this.muc.add('modules_enabled', 'websocket_s2s_peertubelivechat')