redis-dns/server-old.js

Simple DNS server configured using redis. Based on iriscouche's dnsd: https://github.com/iriscouch/dnsd

#!/usr/bin/env node

// server.js
//------------------------------
//
// 2013-08-18, Jonas Colmsjö
//
// Copyright Gizur AB 2013
//
// Simple DNS server based on dnsd developed by iriscouch
//
// Using Google JavaScript Style Guide - http://google-styleguide.googlecode.com/svn/trunk/javascriptguide.xml
//
//------------------------------

var dnsd       = require('dnsd'),
    helpers    = require('helpersjs').create(),
    nconf      = require('nconf');


  nconf.use('file', { file: __dirname + '/redis-dns-config.json' });
  nconf.load();

  this.dnsInterface = nconf.get('dns_interface');
  this.dnsPort      = nconf.get('dns_port');
  this.dnsZone      = nconf.get('dns_zone');
  this.redisHost    = nconf.get('redis_host');
  this.redisPort    = nconf.get('redis_port');

  // set logging level
  switch(nconf.get('logging')) {

    case 'debug':
      helpers.logging_threshold  = helpers.logging.debug;
      break;

    case 'warning':
      helpers.logging_threshold  = helpers.logging.warning;
      break;

    default:
      console.log('error: incorrect logging level in config.json - should be warning or debug!');
  }



function handler(req, res) {

  var question     = res.question[0], 
      hostname     = question.name, 
      length       = hostname.length, 
      ttl          = Math.floor(Math.random() * 3600),
      redis        = require("redis"),
      redis_client = redis.createClient(this.redisHost, this.redisPort);


  var answer = {};

  if(question.type === 'A') {

    // connect to redis
    redis_client.on("connect", function () {

      // first set the IP for the domain in redis
      redis_client.get("redis-dns:"+hostname, function(redis_err, redis_res) {
        if(redis_err) {
          helpers.logErr('Redis error:'+redis_err);
        } else {
          if(redis_res !== null && redis_res.length > 0) {
            answer = {
              name:hostname, 
              type:'A', 
              data:redis_res, 
              'ttl':ttl};

            res.answer.push(answer);
          }
        }
        redis_client.quit();
        console.log('%s:%s/%s question:%j answer:%j', req.connection.remoteAddress, req.connection.remotePort, req.connection.type, question, answer);
        res.end();
      }.bind(this));
    }.bind(this));

    // redis error management
    redis_client.on("error", function (err) {
      console.log("Redis error: " + err);
    });

  } else {
    res.end();
  }

}

var server = dnsd.createServer(handler);
console.log('Server running at'+this.dnsInterface+':'+this.dnsPort);
server.zone(this.dnsZone, 'ns1.'+this.dnsZone, 'us@'+this.dnsZone, 'now', '2h', '30m', '2w', '10m')
      .listen(this.dnsPort, this.dnsInterface);