README.md

What is node.js auto restart

It is a way to watch all .js files if they have been changed and to restart nodejs. It allows easy development and stable production.

How to use nodejs auto restart:

Copy nodejs.sh and autoexit.js to root folder of your application for example to /var/www. Copying of autoexit.js is optional and it can be included from deps folder

Add to your script at top:

require.paths.unshift(__dirname); //make local paths accessible

And to your script at end:

// exit if any js file or template file is changed.
// it is ok because this script encapsualated in a batch while(true);
// so it runs again after it exits.
var autoexit_watch=require('autoexit').watch;
//
var on_autoexit=function () { } 
autoexit_watch(__dirname,".js", on_autoexit);
//autoexit_watch(__dirname+"/templates",".html", on_autoexit);

You might want to use: try-catch that will make your applicaiton not crush on errors

try
{
 //your code
}
catch(e)
{
 sys.puts(e.stack)
}

Example:

require.paths.unshift(__dirname); //make local paths accessible

var sys = require('sys'),
   http = require('http');

http.createServer(function (req, res) {

  try
  {

  res.writeHead(200, {'Content-Type': 'text/plain'});
  res.end('Hello World\n');
  
  }
  catch(e)
  {
   sys.puts(e.stack);
  }
  
}).listen(8124, "127.0.0.1");
sys.puts('Server running at http://127.0.0.1:8124/');

// exit if any js file or template file is changed.
// it is ok because this script encapsualated in a batch while(true);
// so it runs again after it exits.
var autoexit_watch=require('autoexit').watch;
//
var on_autoexit=function () { sys.puts('bye bye'); } 
autoexit_watch(__dirname,".js", on_autoexit);
//autoexit_watch(__dirname+"/templates",".html", on_autoexit);

Edit nodejs.sh

Edit nodejs.sh to match to your server.js filename.

To launch nodejs you type

cd /var/www
./nodejs.sh

To make it work with upstart - run on boot

Copy nodejs.conf to `/etc/init/`` and modify it to point to nodejs.sh

To use upstart you type :

[command] + [init filename without conf extention]

start nodejs 
stop nodejs
restrt nodejs

When i start to develop I connect to the server with ssh and run:

stop nodejs
cd /var/www
./nodejs.sh

Then I will start to see application output and errors on the screen If I want to stop the server I press Control + C and the script stops.

Nginx?

Yes I also use Nginx as front. (but it is not required). I use it to let me in the future to change and integrate different servers seemlessly. It is basicly: nginx<->nodejs as an upstream. also i added php-cgi to nginx to use moadmin.php - mongodb db editor.

Multi Process

you can put nginx or haproxy as a front and create several .conf files for the upstart.

in each you modify the execution line to contain port number ex.: in the nodejs1.conf exec sudo -u www-data /bin/bash /var/www/nodejs-mongodb-app/nodejs.sh 8001 in the nodejs2.conf exec sudo -u www-data /bin/bash /var/www/nodejs-mongodb-app/nodejs.sh 8002

and make port as an argument to your server.js. //http.createServer(server_handler_function).listen(process.argv[2]||8001); //see http://nodejs.org/api.html#process-argv-58 //process.argv.forEach(function (val, index, array) { // console.log(index + ': ' + val); //});

To achive best performance. it was found by testing (during development of twisted and nginx) that the number of processors should much the number of cores not more not lest.

the idea behind the architecture

the idea is to add an extra level of fail-safety by using a stable system shell script to restart node instead of node itself.