coding, javascript, nodejs

Parse Server – providing ip of a client

Very handy code that can be used for analytics (reversing to approximate location)

let ip = request.headers[‘x-forwarded-for’] || request.connection.remoteAddress || request.socket.remoteAddress || request.connection.socket.remoteAddress;

This is for cloud defined functions for your custom rest API

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cloud, coding, mobile, nodejs

Mobile app built in 24 hours for banking

I have participated individually in a hackathon organized by a bank and had a concept in mind that would help bank customers chat with an advisor competent in their field.

I’ve built a platform that had a real time chat, a browser based web app that would be more suitable for Customer Support or Advisor (also a mobile app was available if they were on the go).

The pitch:

Simplifying issue resolution for customers by matching them to advisors and saving time for both sides.


I have open sourced my solution with screenshots.

Available here

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coding, mongodb, nodejs, Uncategorized

Recently open sourced project – toronto open data

The motivation behind this project is


  • Building a very capable api with geo lookups
  • Toronto Open Data api -specifically city services is very slow
  • User interface as a proof of concept which exploits the use of new API
  • Open sourced for others to use and improve

Technology stack:


  • MongoDB
  • NodeJS, rest api, mongoose
  • AngularJS (bootstrap, routes)


GiHub link

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architecture, javascript, nodejs

Official is dead?, long live IOJS

It appears that IOJS (io.js, a form of node.js ) has gained an incredible momentum and credibility. As a seasoned nodeJS engineer i would be strongly swayed towards iojs give that it has all the important committee members (committers to nodejs).

My recent observation of this fork is that they release every 4 days ! That’s an impressive frequency.

Although some are uncertain about this fork in hopes that official (rather original) nodejs may all of a sudden resolve their differences and release 0.12 or perhaps even Nodejs 1.0, we shall see what happens in the next few months.
At one point a plan was to release NodeJS 0.12 in March 2014 , prediction is that it could be this year.

Meanwhile , Strongloop is gaining ground as a promenant NodeJS consulting firm with an array of tools (from monitoring , web ide generating rest apis, etc).


To add to this note, folks are realizing that NPM INSTALL may be something devops have missed and insecure (or plain old malware) modules can be installed ( might be even root).



Feb 11 UPDATE: Official NodeJS 0.12 was released just few days ago albeit without mention of generators. Great news!


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coding, javascript, nodejs

Async map reduce filter using NodeJS and callbacks in parallel

Following up with a series i started earlier

Writing clean code is indeed paramount in our industry and we all aspire to be better at it. With popularization of NodeJS we face another challenge

Our first challenge was to process large set of json objects , filter it by name property and get a total for that group.

This is a traditional JavaScript blocking way of doing it.

var data = []

while( data.length < 100) {
   data.push({name: "it", salary: 33*data.length});
data.push({name: "accounting", salary: 100});

data.push({name: "acc", salary: 100});
var sum = data.filter(function(val){
	return == "it"
	return curr.salary;
.reduce(function(prev, curr){
	return prev +curr;


I thought, well, this can be done in an asynchronous way. I’ve had a great production use of ‘async’ library that works mainly on NodeJS but also in browser.

To ramp up the numbers, we’ll create 3000000 objects.

> Finished iterating , took: 656 Sum 148499950500100

It took 656 ms. That’s pretty quick.

Here is my implementation using Async. Few comments:

Control is passed using callbacks. Iterators in most cases include an object and a callback. Filter is a special case that does not have a typical nodeJS  (err, data) pattern.

async.filter(data, function(item,cb){ == "it" ? cb(true) : cb(false);
}, function(results){,function(item,cb){
	return cb(null,item.salary);
}, function(err,results2){


function(memo, item, cb2){
//functions in a series
		setImmediate(function (){

},function(err, sum){
		end = +new Date();
      var diff = end - start; // time difference in milliseconds
      console.log(" Finished iterating , took: "+diff + " Sum "+sum);



Pretty cool but the numbers… not so good 9.8 seconds, JEEZ

 Finished iterating , took: 9835 Sum 148499950500100

Here is a series problem: reduce is executed in series, meaning it is sequential in terms of getting the final result, that’s a performance bottleneck.

Don’t be alarmed, there is a way and i absolutely tested it.

async.each(data, function(item,cb){
	if ( == "it")
		sum += item.salary;

}, function(err){
	end = +new Date();
      var diff = end - start; // time difference in milliseconds
      console.log(" Finished iterating , took: "+diff + " Sum "+sum);

Async’s each is the most commonly used method for executing in parallel.


Finished iterating , took: 446 Sum 148499950500100

 Much faster!

Async provides a lot of useful methods, one really useful is Sort/Sort By, eachSeries (will execute in sequence) and most important method is Async.parallel([methods to be executed in paralel], callback)


Voila & Thanks



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bigdata, coding, javascript, nodejs

Using sumo logic to query bigdata

Main selling point of Sumologic is: real-time (near) big data forensic capability.

[pullquote]Log data is the fastest-growing and most under-utilized component of Big Data. And no one puts your machine-generated Big Data to work like Sumo Logic[/pullquote]


At Inpowered, we used Sumologic extensively, our brave and knowledgeable DevOps folks managed chef scripts that contained installation of Sumologic’s agents on most instances. What’s great about this:

  • Any application that writes any sort of log, be it a tomcat log (catalina.out)
    or custom log file (i wrote tons of json) , basically any data that’s structured or otherwise is welcome
  • Sumologic behind the scene processes your data seamlessly (with help of hadoop
    and other tools in the background) and you deal with your data using SQL-like language
  • Sumologic can retain gigabytes of data , although there are limits as to what is kept monthly
  • Sumologic has a robust set of functions , from basic avg, sum, count,
    it has PCT (percentile ) – pct(ntime, 90) gives you 90th percentile of some column
  • Sumo has a search API, allowing you to run your search query ,
    suspend process in the background and return
  • Sumo’s agent can be installed on hundreds of your ec2 machines (or whatever)
    and each machine can have multiple collectors (think of collector as a source of logs)
  • Besides an easy access to your data (through collectors on hundreds of machines) ,
    very useful dashboard with autocomplete field for your query is easy to use
  • Another cool feature is “Summarizing” within your search query,
    allowing you to group data via some sort of pattern into clusters
  • Oh! And you get to use timeslicing when dealing with your data


Getting started guide can be found here 

High level overview how Sumologic processes data behind the scene (img from sumologic)


 How could we live without an API?!


Sumologic wouldn’t great if it hadn’t offered us to run queries ourselves using whatever tools we want.

This can be achieved fairly easily using their Search job API , here is an example that parses log files that contain 10.343 sec —-< action name> . Somewhat a common usecase where an app logs these things and i want to know which are the slowest, whats the 90th percentile and what were the actions within certain time range and sliced by hour so that i don’t get too much data. Just an example written in nodeJS.

query_messages – query that will return you all the messages with actions that were slow

query – query that will provide you statistics and 90th percentile, sorted result

var request = require('request'),
    username = "[email protected]",
    password = "somepass",
    url = "",
    query_messages = '_collector=somesystem-prd* _source=httpd "INFO"| parse "[* (" as ntype  | parse "--> *sec" as time | num(time) as ntime | timeslice by 1h |  where ntime > 7 | where !(ntype matches "Dont count me title")   | sort by ntime',
    query = '_collector=somesystem-prd* _source=httpd "INFO"| parse "[* (" as ntype  | parse "--> *sec" as time | num(time) as ntime | timeslice by 1h |  where ntime > 7 | where !(ntype matches "dont count me title")  | max(ntime), min(ntime), pct(ntime, 90)  by _timeslice | sort by _ntime_pct_90 desc'

var qs = require('querystring');
var util = require('util'); 
from = "2014-01-21T10:00:00";
to = "2013-01-21T17:00:00"

	var params = {
    		q: query_messages,
    		from: from,
    		to: to

    	params = qs.stringify(params);    
    url = url + "?"+ params;
    	'auth': {
    		'user': username,
    		'pass': password,
    		'sendImmediately': false
    function (error, response, body) {
    	if (!error && response.statusCode == 200) {
    		var json = JSON.parse(body);
    		console.log(">>> ERrror "+error + " code: "+response.statusCode);

    function insp(obj){
	console.log(util.inspect(obj, false, null));

Now you have an example and you can work with your data , transform it, send a cool notification to a team, etc etc.

Thanks and enjoy Sumologic (free with 500Megs daily )


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