simple-koa-server.js

var path = require('path');
var cluster = require('cluster');
var bootable = require('bootable');
var bootableEnv = require('bootable-environment');
var spdy = require('spdy');
var keys = require('spdy-keys');
var koa = require('koa');
var app;

if (cluster.isMaster) {
    cluster.fork();
    cluster.on('listening', function (worker) {
        worker.on('exit', function () {
            console.error('Worker ' + worker.process.pid + ' died, forking new one');
            cluster.fork();
        });
    });

} else {
    app = bootable(koa());
    app.keys = ['some secret'];
    // Configure for NODE_ENV, make application initialization, attach middleware and routes
    app.phase(bootableEnv('config/environments'));
    app.phase(bootable.initializers(__dirname + '/config/initializers'));
    app.phase(bootable.initializers(__dirname + '/config/middleware'));
    /**√
     * Creates ready for SPDY server.
     */
    app.phase(function () {
        var host = this.config.host;
        var port = this.config.port;
        var secure = this.config.secure;

        // For plain HTTP use `{plain: true, ssl: false}` instead `keys`.
        // Also server instance is stored in `_server` member for webpack middleware.
        var server = this._server = secure ?
            spdy.createServer(keys, this.callback()) :
            spdy.createServer({plain: true, ssl: false}, this.callback());

        server.listen(port, host, function(err) {
            if (err) return;
            console.info('HTTP server listening on http%s://%s:%d (%s)',
                secure ? 's' : '', host, port, process.pid);
        });

        process.on('uncaughtException', function (err) {
            console.error('UNCAUGHT EXCEPTION:', err.stack);
            server.close(function () {
                process.exit(1);
            });
            setTimeout(function () {
                process.exit(1);        //exit anyway after 2s
            }, 2000);
        }.bind(this));
    });

    app.boot(function(err) {
        if (err) throw err;
    });
}