graceful restart

server.js

var net = require('net')
var child_process = require('child_process')

var number = process.argv.length > 2 ? parseInt(process.argv[2], 10) : 0;

function listen(server) {
    server.on('connection', function(socket) {
        socket.write('hi from #'+number+'\n');
    });

    process.on('SIGHUP', function() {
        console.log('#'+number+" got SIGHUP");
        var child = child_process.fork(process.argv[1], [number+1]);

        child.on('message', function(message) {
            if(message.ready) {
                child.send({}, server);
            } else if(message.die) {
                console.log("process #"+number+" dying");
                server.close(function() {
                    console.log("#"+number+" done");
                    process.exit(0);
                });
            }
        });
    });

}


if(process.send) {
    process.send({ready: 1});
    process.on('message', function(message, server) {
        listen(server);
        console.log("process #"+number+" ready and killing parent");
        process.send({die: 1});
    });
}
else {
    var server = net.createServer();
    server.listen(3000);
    listen(server);
}