Implement delayed server shutdown with cancelation (#4664)

builtin/game/chatcommands.lua

@@ -763,14 +763,20 @@ core.register_chatcommand("days", {
 
 core.register_chatcommand("shutdown", {
 	description = "Shutdown server",
-	params = "[reconnect] [message]",
+	params = "[delay_in_seconds(0..inf) or -1 for cancel] [reconnect] [message]",
 	privs = {server=true},
 	func = function(name, param)
-		core.log("action", name .. " shuts down server")
-		core.chat_send_all("*** Server shutting down (operator request).")
-		local reconnect, message = param:match("([^ ]+)(.*)")
+		local delay, reconnect, message = param:match("([^ ][-]?[0-9]+)([^ ]+)(.*)")
 		message = message or ""
-		core.request_shutdown(message:trim(), core.is_yes(reconnect))
+
+		if delay ~= "" then
+			delay = tonumber(param) or 0
+		else
+			delay = 0
+			core.log("action", name .. " shuts down server")
+			core.chat_send_all("*** Server shutting down (operator request).")
+		end
+		core.request_shutdown(message:trim(), core.is_yes(reconnect), delay)
 	end,
 })
 

builtin/game/misc.lua

@@ -173,3 +173,8 @@ end
 function core.close_formspec(player_name, formname)
 	return minetest.show_formspec(player_name, formname, "")
 end
+
+function core.cancel_shutdown_requests()
+	core.request_shutdown("", false, -1)
+end
+

doc/lua_api.txt

@@ -2576,8 +2576,12 @@ These functions return the leftover itemstack.
     * Optional: Variable number of arguments that are passed to `func`
 
 ### Server
-* `minetest.request_shutdown([message],[reconnect])`: request for server shutdown. Will display `message` to clients,
-    and `reconnect` == true displays a reconnect button.
+* `minetest.request_shutdown([message],[reconnect],[delay])`: request for server shutdown. Will display `message` to clients,
+    `reconnect` == true displays a reconnect button,
+    `delay` adds an optional delay (in seconds) before shutdown
+        negative delay cancels the current active shutdown
+        zero delay triggers an immediate shutdown.
+* `minetest.cancel_shutdown_requests()`: cancel current delayed shutdown
 * `minetest.get_server_status()`: returns server status string
 * `minetest.get_server_uptime()`: returns the server uptime in seconds
 

src/network/serverpackethandler.cpp

@@ -722,6 +722,13 @@ void Server::handleCommand_ClientReady(NetworkPacket* pkt)
 
 	m_clients.event(peer_id, CSE_SetClientReady);
 	m_script->on_joinplayer(playersao);
+	// Send shutdown timer if shutdown has been scheduled
+	if (m_shutdown_timer > 0.0f) {
+		std::wstringstream ws;
+		ws << L"*** Server shutting down in "
+				<< duration_to_string(round(m_shutdown_timer)).c_str() << ".";
+		SendChatMessage(pkt->getPeerId(), ws.str());
+	}
 }
 
 void Server::handleCommand_GotBlocks(NetworkPacket* pkt)

src/script/lua_api/l_server.cpp

@@ -33,7 +33,8 @@ int ModApiServer::l_request_shutdown(lua_State *L)
 	NO_MAP_LOCK_REQUIRED;
 	const char *msg = lua_tolstring(L, 1, NULL);
 	bool reconnect = lua_toboolean(L, 2);
-	getServer(L)->requestShutdown(msg ? msg : "", reconnect);
+	float seconds_before_shutdown = lua_tonumber(L, 3);
+	getServer(L)->requestShutdown(msg ? msg : "", reconnect, seconds_before_shutdown);
 	return 0;
 }
 

src/server.cpp

@@ -177,6 +177,7 @@ Server::Server(
 	m_clients(&m_con),
 	m_shutdown_requested(false),
 	m_shutdown_ask_reconnect(false),
+	m_shutdown_timer(0.0f),
 	m_admin_chat(iface),
 	m_ignore_map_edit_events(false),
 	m_ignore_map_edit_events_peer_id(0),
@@ -1029,6 +1030,39 @@ void Server::AsyncRunStep(bool initial_step)
 			m_env->saveMeta();
 		}
 	}
+
+	// Timed shutdown
+	static const float shutdown_msg_times[] =
+	{
+		1, 2, 3, 4, 5, 10, 15, 20, 25, 30, 45, 60, 120, 180, 300, 600, 1200, 1800, 3600
+	};
+
+	if (m_shutdown_timer > 0.0f) {
+		// Automated messages
+		if (m_shutdown_timer < shutdown_msg_times[ARRLEN(shutdown_msg_times) - 1]) {
+			for (u16 i = 0; i < ARRLEN(shutdown_msg_times) - 1; i++) {
+				// If shutdown timer matches an automessage, shot it
+				if (m_shutdown_timer > shutdown_msg_times[i] &&
+					m_shutdown_timer - dtime < shutdown_msg_times[i]) {
+					std::wstringstream ws;
+
+					ws << L"*** Server shutting down in "
+						<< duration_to_string(round(m_shutdown_timer - dtime)).c_str()
+						<< ".";
+
+					infostream << wide_to_utf8(ws.str()).c_str() << std::endl;
+					SendChatMessage(PEER_ID_INEXISTENT, ws.str());
+					break;
+				}
+			}
+		}
+
+		m_shutdown_timer -= dtime;
+		if (m_shutdown_timer < 0.0f) {
+			m_shutdown_timer = 0.0f;
+			m_shutdown_requested = true;
+		}
+	}
 }
 
 void Server::Receive()
@@ -3443,6 +3477,39 @@ v3f Server::findSpawnPos()
 	return nodeposf;
 }
 
+void Server::requestShutdown(const std::string &msg, bool reconnect, float delay)
+{
+	if (delay == 0.0f) {
+	// No delay, shutdown immediately
+		m_shutdown_requested = true;
+	} else if (delay < 0.0f && m_shutdown_timer > 0.0f) {
+	// Negative delay, cancel shutdown if requested
+		m_shutdown_timer = 0.0f;
+		m_shutdown_msg = "";
+		m_shutdown_ask_reconnect = false;
+		m_shutdown_requested = false;
+		std::wstringstream ws;
+
+		ws << L"*** Server shutdown canceled.";
+
+		infostream << wide_to_utf8(ws.str()).c_str() << std::endl;
+		SendChatMessage(PEER_ID_INEXISTENT, ws.str());
+	} else if (delay > 0.0f) {
+	// Positive delay, delay the shutdown
+		m_shutdown_timer = delay;
+		m_shutdown_msg = msg;
+		m_shutdown_ask_reconnect = reconnect;
+		std::wstringstream ws;
+
+		ws << L"*** Server shutting down in "
+				<< duration_to_string(round(m_shutdown_timer)).c_str()
+				<< ".";
+
+		infostream << wide_to_utf8(ws.str()).c_str() << std::endl;
+		SendChatMessage(PEER_ID_INEXISTENT, ws.str());
+	}
+}
+
 PlayerSAO* Server::emergePlayer(const char *name, u16 peer_id, u16 proto_version)
 {
 	bool newplayer = false;

src/server.h

@@ -226,12 +226,7 @@ class Server : public con::PeerHandler, public MapEventReceiver,
 	inline bool getShutdownRequested() const { return m_shutdown_requested; }
 
 	// request server to shutdown
-	void requestShutdown(const std::string &msg, bool reconnect)
-	{
-		m_shutdown_requested = true;
-		m_shutdown_msg = msg;
-		m_shutdown_ask_reconnect = reconnect;
-	}
+	void requestShutdown(const std::string &msg, bool reconnect, float delay = 0.0f);
 
 	// Returns -1 if failed, sound handle on success
 	// Envlock
@@ -602,6 +597,7 @@ class Server : public con::PeerHandler, public MapEventReceiver,
 	bool m_shutdown_requested;
 	std::string m_shutdown_msg;
 	bool m_shutdown_ask_reconnect;
+	float m_shutdown_timer;
 
 	ChatInterface *m_admin_chat;
 	std::string m_admin_nick;

src/util/string.h

@@ -614,4 +614,28 @@ inline const char *bool_to_cstr(bool val)
 	return val ? "true" : "false";
 }
 
+inline const std::string duration_to_string(int sec)
+{
+	int min = floor(sec / 60);
+	sec %= 60;
+	int hour = floor(min / 60);
+	min %= 60;
+
+	std::stringstream ss;
+	if (hour > 0) {
+		ss << hour << "h ";
+	}
+
+	if (min > 0) {
+		ss << min << "m ";
+	}
+
+	if (sec > 0) {
+		ss << sec << "s ";
+	}
+
+	return ss.str();
+}
+
+
 #endif