main.js

var fs = require('fs');
var Metrics = require('./metrics');
var ProductionConfig = require('./productionconfig');
var _ = require('underscore');


function main(config) {
    var Log = require('log');
    switch(config.debug_level) {
        case "error":
            log = new Log(Log.ERROR); break;
        case "debug":
            log = new Log(Log.DEBUG); break;
        case "info":
            log = new Log(Log.INFO); break;
    };

    var production_config = new ProductionConfig(config);
    if(production_config.inProduction()) {
        _.extend(config, production_config.getProductionSettings());
    }

    var ws = require("./ws");
    var WorldServer = require("./worldserver");
    var server = new ws.WebsocketServer(config.port, config.use_one_port, config.ip);
    var metrics = config.metrics_enabled ? new Metrics(config) : null;
    var worlds = [];
    var lastTotalPlayers = 0;
    var DatabaseSelector = require("./databaseselector");
    var checkPopulationInterval = setInterval(function() {
        if(metrics && metrics.isReady) {
            metrics.updateWorldCount();
            metrics.getTotalPlayers(function(totalPlayers) {
                if(totalPlayers !== lastTotalPlayers) {
                    lastTotalPlayers = totalPlayers;
                    _.each(worlds, function(world) {
                        world.updatePopulation(totalPlayers);
                    });
                }
            });
        }
    }, 1000);

    log.info("Starting BrowserQuest game server...");
    var selector = DatabaseSelector(config);
    databaseHandler = new selector(config);

    server.onConnect(function(connection) {
        var world; // the one in which the player will be spawned
        var connect = function() {
                if(world) {
                    world.connect_callback(new Player(connection, world, databaseHandler));
                }
            };

        if(metrics) {
            metrics.getOpenWorldCount(function(open_world_count) {
                // choose the least populated world among open worlds
                world = _.min(_.first(worlds, open_world_count), function(w) { return w.playerCount; });
                connect();
            });
        }
        else {
            // simply fill each world sequentially until they are full
            world = _.find(worlds, function(world) {
                return world.playerCount < config.nb_players_per_world;
            });
            world.updatePopulation();
            connect();
        }
    });

    server.onError(function() {
        log.error(Array.prototype.join.call(arguments, ", "));
    });

    var onPopulationChange = function() {
        metrics.updatePlayerCounters(worlds, function(totalPlayers) {
            _.each(worlds, function(world) {
                world.updatePopulation(totalPlayers);
            });
        });
        metrics.updateWorldDistribution(getWorldDistribution(worlds));
    };

    _.each(_.range(config.nb_worlds), function(i) {
        var world = new WorldServer('world'+ (i+1), config.nb_players_per_world, server, databaseHandler);
        world.run(config.map_filepath);
        worlds.push(world);
        if(metrics) {
            world.onPlayerAdded(onPopulationChange);
            world.onPlayerRemoved(onPopulationChange);
        }
    });

    server.onRequestStatus(function() {
        return JSON.stringify(getWorldDistribution(worlds));
    });

    if(config.metrics_enabled) {
        metrics.ready(function() {
            onPopulationChange(); // initialize all counters to 0 when the server starts
        });
    }

    process.on('uncaughtException', function (e) {
        // Display the full error stack, to aid debugging
        log.error('uncaughtException: ' + e.stack);
    });
}

function getWorldDistribution(worlds) {
    var distribution = [];

    _.each(worlds, function(world) {
        distribution.push(world.playerCount);
    });
    return distribution;
}

function getConfigFile(path, callback) {
    fs.readFile(path, 'utf8', function(err, json_string) {
        if(err) {
            console.info("This server can be customized by creating a configuration file named: " + err.path);
            callback(null);
        } else {
            callback(JSON.parse(json_string));
        }
    });
}

var defaultConfigPath = './server/config.json';
var customConfigPath = './server/config_local.json';

process.argv.forEach(function (val, index, array) {
    if(index === 2) {
        customConfigPath = val;
    }
});

getConfigFile(defaultConfigPath, function(defaultConfig) {
    getConfigFile(customConfigPath, function(localConfig) {
        if(localConfig) {
            main(localConfig);
        } else if(defaultConfig) {
            main(defaultConfig);
        } else {
            console.error("Server cannot start without any configuration file.");
            process.exit(1);
        }
    });
});