simple node.js server that prints hostname and instance-id, with custom response time

README.md

Notes

Defaults:

1s response

port 3000

Usage

Point browser to http://<hostname>:<port>[?query=<timeout>]

Or run curl http://<hostname>:<port>[?query=<timeout>]

server.js

// Load the http module to create an http server.
var http = require('http');
var url =  require('url');

var config = {};
config.port = process.env.PORT || 3000; // default port 3000
config.timeout = 1000; // default timeout (ms)

// Configure our HTTP server to respond with Hello World to all requests.
var server = http.createServer(function (request, response) {

  response.writeHead(200, {"Content-Type": "text/plain"});
  console.log(request.url);
  
  // Start time
  response.write('\n start = ' + new Date().toString() + '\n');
  getmetadata('latest/meta-data/public-hostname/',function(d) {response.write('\n'+d+'\n')});
  getmetadata('latest/meta-data/instance-id/',function(d) {response.write('\n'+d+'\n')});

  var urlparts = url.parse(request.url,true);
  var timeout = urlparts.query.query || config.timeout;
  
  setTimeout(function() {
  // End time
    response.end('\n end = ' + new Date().toString() + '\n');
  }, timeout );

});

// Server listens on port from config
server.listen(config.port);
console.log("Server running at port "+config.port);

// GET metadata
var getmetadata = function(path,cb) {

        var mdsvr = {};
        mdsvr.hostname= '169.254.169.254';
        mdsvr.path= path;

        console.log("getting " + path);
        http.get(mdsvr, function(res) {
                res.setEncoding('utf8');
                var body = '';
                res.on('data', function(d) { body += d; });
                res.on('end', function() { cb(body); });
        }).on('error', function(e) {
                console.log("Got error: " + e.message);
        });

}