index.js

var redisWrapper = require('./redisWrapper.js');
var events       = require('events');

var redis        = require('redis');
var client       = redis.createClient();

/**                                                                                                                                                                                                                                                                                                                                                                                                                                          
 * Global event emitter                                                                                                                                                                                                                                                                                                                                                                                                                      
 */
global._ev = new events.EventEmitter();

/**                                                                                                                                                                                                                                                                                                                                                                                                                                          
 * Wrap redis                                                                                                                                                                                                                                                                                                                                                                                                                                
 */
redisWrapper(redis);

global._ev.on('query', function(dt) {
  console.log(dt);
});

/**                                                                                                                                                                                                                                                                                                                                                                                                                                          
 * Do queries                                                                                                                                                                                                                                                                                                                                                                                                                                
 */
setInterval(function() {
  client.set("string key", "string val", redis.print);
  client.hset(["hash key", "hashtest 2", "some other value"], redis.print);
}, 3000);

proxy.js

var debug = require('debug')('proxy');

// var cls     = require('continuation-local-storage');                                                                                                                                             
// var ns      = cls.createNamespace('namespace');                                                                                                                                                  

var Proxy = module.exports = {
  wrap : function(object, methods, hook) {
    var self = this;

    if (!Array.isArray(methods)) methods = [methods];

    methods.forEach(function(method) {
      var original = object[method];
      if (!original) return debug('Method %s unknown', method);
      if (original.__axm_original) return debug('Already wrapped', object);

      var hooked = hook(original);

      hooked.__axm_original = original;
      object[method] = hooked;
      debug('Method proxified');
    });
  }
};

redisWrapper.js

var Proxy   = require('./proxy.js');

var RedisWrap = module.exports = function(redis) {
  Proxy.wrap(redis.RedisClient.prototype, 'send_command', function(send_command) {
    return function() {
      var cmd = arguments[0];
      var fn_args = arguments[arguments.length - 1];
      var cb = fn_args[fn_args.length - 1];

      var args = arguments;

      var begin = Date.now();

      function end() {
        global._ev.emit('query', {
          time  : Date.now() - begin,
          type  : 'redis',
          at    : Date.now(),
          query : fn_args,
          cmd   : cmd
        });
      }

      if (typeof cb === 'function')
        cb = end(cb);
      else
        end();

      send_command.apply(this, arguments);

    };
  });
  return redis;
};