tileserver.js

/*
node-tileserver Copyright (C) 2014 Alexander Matheisen
This program comes with ABSOLUTELY NO WARRANTY.
This is free software, and you are welcome to redistribute it under certain conditions.
See https://github.com/rurseekatze/node-tileserver for details.
*/


// include necessary modules
var cluster = require('cluster');
var os = require('os');
var rbush = require('rbush');
var assert = require('assert');
var http = require("http");
var url = require("url");
var toobusy = require('toobusy-js');
var byline = require('byline');
var touch = require("touch");
var Canvas = require('canvas');
var events = require('events');
var log4js = require('log4js');
var fs = require('graceful-fs');
var pgPass = require('pgpass');
var Pool = require('pg-pool');

// load configuraion file
configuration = require('./config.json');

// configure logging
log4js.configure(
{
	appenders:
	[
		{
			"type": "logLevelFilter",
			"level": "ERROR",
			"appender":
			{
				"type": "file",
				"filename": 'tileserver.log',
				'maxLogSize': 20480,
				'backups': 0
			}
		},
		{
			"type": "logLevelFilter",
			"level": "DEBUG",
			"appender":
			{
				"type": "console"
			}
		}
	]
});

logger = log4js.getLogger();
logger.setLevel('INFO');

Tile = require('./tile.js');
Tilerequest = require('./tilerequest.js');
Tilequeue = require('./queue.js');

// number of cpus
var cpus = os.cpus().length;

// maximum count of concurrent http connections
http.globalAgent.maxSockets = configuration.maxsockets;

// request password from pgpass only once at startup, not for each process or even each request
var connectionDetails =
{
	'host' : 'localhost',
	'port': configuration.port,
	'database': configuration.database,
	'user' : configuration.username,
	'max': parseInt(configuration.maxPoolSize / cpus),
	'idleTimeoutMillis': 10000
};

pgPass(connectionDetails, function(password)
{
	if (typeof password == 'undefined')
	{
		logger.fatal('PGPASS file cannot be read or no matching line for given connection info found');
		process.exit(1);
	}

	logger.debug('Successfully read password using PGPASS');
	configuration.password = password;

	// fork workers
	if (cluster.isMaster)
	{
		for (var i=0; i<cpus; i++)
			cluster.fork();
		cluster.on("exit", function(worker, code, signal)
		{
			logger.fatal("WORKER STOPPED");
			cluster.fork();
		});
		logger.info('Master has started.');
	}
	// start tile server instance
	else
	{
		// handle exceptions
		process.on('uncaughtException', function(err)
		{
			logger.fatal('An uncaughtException occurred:');
			logger.fatal(err);
			process.exit(1);
		});

		// rendering queue for expired tiles
		queue = new Tilequeue();

		pool = new Pool(connectionDetails);
		pool.on('error', function (err, client)
		{
			logger.error('Idle database client error: ' + err.message)
		});

		function onRequest(request, response)
		{
			if (toobusy())
			{
				logger.info('Server too busy. Aborting.');
				response.writeHead(503, {'Content-Type': 'text/plain'});
				response.end();
				return;
			}
			else
			{
				var tilerequest = new Tilerequest(request, response);
				tilerequest.getTile();
				tilerequest = null;
			}
		}

		http.createServer(onRequest).listen(configuration.tileserverPort);
		logger.info('Worker has started.');
	}
});