Backported graceful restart feature to server

changelog

@@ -5,6 +5,7 @@ Version 1.4.2+svn:
    * starting a campaing without any installed now gives an error.
    * fixed issues with campaign info in non-compressed saved games
      (bug #11386)
+   * Backported gracefull restart feature to server
    * fixed an alignement issue which caused a SIGBUS on a Sparc 
      (debian bug #426318)
    * added some includes to fix compilation problems with Sun Studio 12 

src/multiplayer_connect.cpp

@@ -1082,6 +1082,11 @@ void connect::process_network_data(const config& data, const network::connection
 {
 	ui::process_network_data(data, sock);
 
+	if(data.child("leave_game")) {
+		set_result(QUIT);
+		return;
+	}
+
 	if (!data["side_drop"].empty()) {
 		const int side_drop = lexical_cast_default<int>(data["side_drop"], 0) - 1;
 		if(side_drop >= 0 && side_drop < int(sides_.size())) {

src/network.cpp

@@ -160,6 +160,7 @@ static void check_timeout()
 	// Reset last_ping if we didn't check for the last 10s.
 	if (last_ping_check + 10 <= now) last_ping = now;
 	if (static_cast<time_t>(last_ping + network::ping_timeout) <= now) {
+
 		int timeout = now - last_ping;
 		ERR_NW << "No server ping since " << timeout
 				<< " seconds. Connection timed out.\n";
@@ -291,10 +292,16 @@ server_manager::server_manager(int port, CREATE_SERVER create_server) : free_(fa
 }
 
 server_manager::~server_manager()
+{
+	stop();
+}
+
+void server_manager::stop()
 {
 	if(free_) {
 		SDLNet_TCP_Close(server_socket);
 		server_socket = 0;
+		free_ = false;
 	}
 }
 
@@ -448,8 +455,10 @@ void connect_operation::run()
 	while(!notify_finished());
 }
 
+
 } // end namespace
 
+
 connection connect(const std::string& host, int port)
 {
 	connect_operation op(host,port);

src/network.hpp

@@ -79,6 +79,7 @@ struct server_manager {
 	~server_manager();
 
 	bool is_running() const;
+	void stop();
 
 private:
 	bool free_;

src/server/input_stream.cpp

@@ -51,10 +51,18 @@ input_stream::input_stream(const std::string& path) : fd_(-1), path_(path)
 
 input_stream::~input_stream()
 {
+#ifndef _WIN32
+	stop();
+#endif
+}
+
+void input_stream::stop()
+{
 #ifndef _WIN32
 	if(fd_ != -1) {
 		close(fd_);
 		unlink(path_.c_str());
+		fd_ = -1;
 	}
 #endif
 }

src/server/input_stream.hpp

@@ -25,6 +25,7 @@ public:
 	~input_stream();
 
 	bool read_line(std::string& str);
+	void stop();
 
 private:
 	input_stream(const input_stream&);

src/server/server.cpp

@@ -224,7 +224,7 @@ private:
 	void send_error(network::connection sock, const char* msg) const;
 	void send_error_dup(network::connection sock, const std::string& msg) const;
 	const network::manager net_manager_;
-	const network::server_manager server_;
+	network::server_manager server_;
 
 	//! std::map<network::connection,player>
 	player_map players_;
@@ -252,6 +252,8 @@ private:
 	size_t default_max_messages_;
 	size_t default_time_period_;
 	size_t concurrent_connections_;
+	bool gracefull_restart;
+	std::string restart_command;
 	//! Parse the server config into local variables.
 	void load_config();
 	
@@ -289,6 +291,8 @@ private:
 	void delete_game(std::vector<game*>::iterator game_it);
 
 	void update_game_in_lobby(const game* g, network::connection exclude=0);
+
+	void start_new_server();
 };
 
 server::server(int port, input_stream& input, const std::string& config_file, size_t min_threads,size_t max_threads)
@@ -299,6 +303,7 @@ server::server(int port, input_stream& input, const std::string& config_file, si
 	input_(input), 
 	config_file_(config_file),
 	cfg_(read_config()), 
+	gracefull_restart(false),
 	version_query_response_("[version]\n[/version]\n", simple_wml::INIT_COMPRESSED),
 	login_response_("[mustlogin]\n[/mustlogin]\n", simple_wml::INIT_COMPRESSED), 
 	join_lobby_response_("[join_lobby]\n[/join_lobby]\n", simple_wml::INIT_COMPRESSED),
@@ -373,6 +378,10 @@ void server::load_config() {
 			lexical_cast_default<size_t>(cfg_["messages_time_period"],10);
 	concurrent_connections_ =
 			lexical_cast_default<size_t>(cfg_["connections_allowed"],5);
+	// Example config line: 
+	// restart_command="./wesnothd-debug -d -c ~/.wesnoth1.5/server.cfg"
+	// remember to make new one as a daemon or it will block old one
+	restart_command = cfg_["restart_command"];
 
 	accepted_versions_.clear();
 	const std::string& versions = cfg_["versions_accepted"];
@@ -443,9 +452,22 @@ void server::dump_stats(const time_t& now) {
 }
 
 void server::run() {
+	int gracefull_counter = 0;
 	for (int loop = 0;; ++loop) {
 		SDL_Delay(20);
 		try {
+			// We are going to waith 10 seconds before shutting down so users can get out of game.
+			if (gracefull_restart && games_.size() == 0 && ++gracefull_counter > 500 )
+			{
+				// TODO: We should implement client side autoreconnect.
+				// Idea:
+				// server should send [reconnect]host=host,port=number[/reconnect]
+				// Then client would reconnect to new server automaticaly.
+				// This would also allow server to move to new port or address if there is need
+
+				lobby_.send_server_message("Server is restarting. You can connect to new server now.");
+				throw network::error("shut down");
+			}
 			if (config_reload == 1) {
 				cfg_ = read_config();
 				load_config();
@@ -553,7 +575,7 @@ void server::run() {
 				{
 					network::disconnect(pl->first);
 				}
-				std::cout << "Shutting server down.\n";
+				LOG_SERVER << "Shutting server down.\n";
 				break;
 			}
 			if (!e.socket) {
@@ -836,6 +858,18 @@ void server::process_query(const network::connection sock,
 	lobby_.send_server_message(response.str().c_str(), sock);
 }
 
+void server::start_new_server() {
+	if (restart_command.empty())
+		return;
+
+	// Example config line: 
+	// restart_command="./wesnothd-debug -d -c ~/.wesnoth1.5/server.cfg"
+	// remember to make new one as a daemon or it will block old one
+	std::system(restart_command.c_str());
+
+	LOG_SERVER << "New server started with command: " << restart_command << "\n";
+}
+
 std::string server::process_command(const std::string& query) {
 	std::ostringstream out;
 	const std::string::const_iterator i = std::find(query.begin(),query.end(),' ');
@@ -845,9 +879,41 @@ std::string server::process_command(const std::string& query) {
 	const std::string& help_msg = "Available commands are: ban(s) [<mask>] [<reason>],"
 			"kick <mask>, k(ick)ban [<mask>] [<reason>], help, metrics, netstats,"
 			" (lobby)msg <message>, motd [<message>], status [<mask>],"
-			" unban <ipmask>";
+			" unban <ipmask>, shut_down [now], restart";
 	if (command == "shut_down") {
-		throw network::error("shut down");
+		
+		if (parameters == "now")
+			throw network::error("shut down");
+		else
+		{
+			// Gracefull shut down
+			server_.stop();
+			input_.stop();
+			gracefull_restart = true;
+			process_command("msg Server is shuting down. No more new games.");
+			out << "Server is doing gracefull shutdown\n";
+		}
+
+#ifndef _WIN32  // Not sure if this works on windows
+		// TODO: check if this works in windows.
+	} else if (command == "restart") {
+		if (restart_command.empty())
+		{
+			out << "Server isn't configured for restart\n";
+		}
+		else
+		{
+			LOG_SERVER << "Gracefull restart requested\n";
+			gracefull_restart = true;
+			// stop listening socket
+			server_.stop();
+			input_.stop();
+			// start new server
+			start_new_server();
+			process_command("msg Server has been restarted. You can continue playing but new players cannot join this server.");
+			out << "New server strated.\n";
+		}
+#endif
 	} else if (command == "help") {
 		out << help_msg;
 	} else if (command == "metrics") {
@@ -1224,6 +1290,7 @@ void server::process_data_game(const network::connection sock,
 			lobby_.send_server_message(msg.str().c_str(), sock);
 			return;
 		}
+		
 		// If this game is having its level data initialized
 		// for the first time, and is ready for players to join.
 		// We should currently have a summary of the game in g->level().
@@ -1302,6 +1369,11 @@ void server::process_data_game(const network::connection sock,
 		make_add_diff(*games_and_users_list_.child("gamelist"), "gamelist", "game", diff);
 		lobby_.send_data(diff);
 
+		if (gracefull_restart)
+		{
+			delete_game(itor);
+			lobby_.send_server_message("You aren't allowed to make new game because server has been resarted. Please, reconnect to new server.", sock);
+		}
 		//! @todo FIXME: Why not save the level data in the history_?
 		return;
 // Everything below should only be processed if the game is already intialized.
@@ -1551,7 +1623,7 @@ void server::delete_game(std::vector<game*>::iterator game_it) {
 		gamelist->remove_child("game", index);
 	} else {
 		// Can happen when the game ends before the scenario was transfered.
-		DBG_SERVER << "Could not find game (" << (*game_it)->id()
+		LOG_SERVER << "Could not find game (" << (*game_it)->id()
 			<< ") to delete in games_and_users_list_.\n";
 	}
 	const user_vector& users = (*game_it)->all_game_users();

utils/mp-server/run_server

@@ -1,4 +1,10 @@
 #!/bin/sh
+#
+#Example wesnothd.cfg
+#versions_accepted="1.5.0+svn"
+#restart_command="/home/user/source/trunk/utils/mp-server/run_server 1.5 &"
+#
+
 if [ $# -lt 1 ]; then
 	echo "Syntax: $0 <server version> [<additional parameters for wesnothd>]"
 	exit 1
@@ -29,9 +35,6 @@ trap "$HOME/bin/send_server_message $SERVER; sleep 2; $HOME/bin/send_server_comm
 
 while [ true ] 
 do
-	if ps -C wesnothd-$SERVER >/dev/null; then
-		sleep 10
-	else
 		DATE=$(date +"%Y%m%d-%H%M%S")
 		PORT=$(cat $SERVERBASE/port)
 		REV=$(ls -l $SERVERBASE/build | sed -e 's,.*wesnothd-\(svn-.*\)_.*/,\1,')
@@ -55,6 +58,13 @@ do
 		fi
 		# wait for the server to terminate
 		wait $PID
+		EXIT_CODE=$?
+		echo "wesnoth exited with code: ${EXIT_CODE}"
 		cd
-	fi
+
+		# check for return code if not zero server should be restarted
+		if [ "$EXIT_CODE" = "0" ]; then
+			echo "script shutting down"
+			exit 0
+		fi
 done