My Standalone Complexities: hacks

Showing posts with label hacks. Show all posts

Tuesday, January 26, 2016

Getting started on Go Lang with Slack

It is a Republic Day today here in India, January 26th and a national holiday. During one of our random morning conversations with Manoj. Hashicorp cropped up into the topic and that quickly escalated to "Go Lang".

Go Lang has been on my radar for quite some time. I wanted to get started with the language. It's my personal thing that lots of new tools and products are being built on Go and I'm still stuck with JVM. After all moving to Devops demands some change in how I operate right? 😃

While getting started with a new programming language, I always write a simple tool using it and open source it. I wrote a Live NSE Stock information fetcher while I was learning NodeJS 4 years ago and a uClassify Scala client while I was getting started with Scala 3 years ago.

On the similar lines, introducing Slack webhooks library in Go. It's similar to it's Java counterpart, it helps you post messages to slack using a Incoming Webhook url.

Github - https://github.com/ashwanthkumar/slack-go-webhook
Usage - https://github.com/ashwanthkumar/slack-go-webhook/blob/master/README.md

This is still my first Go lang code so any kind of feedback will be helpful.

Friday, September 25, 2015

Winning Amaz-ing Hackathon - Meghadūta

Last weekend was fun at Chennai Amazon office. In association with Venture City, Kindle Team at Chennai organized a hackathon on the theme - "Building Scalable Distributed Systems". The name was theme was good enough to attract me to register for the event :) I went there with Salaikumar and Vijay Kumar to the event under the team name - "Salaikumar".

You can find the problem statements given at the hackathon here.

We won two awards at the event - "Best Voted Award" and "Ultimate Hack Award".

You can find our code at https://github.com/ashwanthkumar/meghaduta.

Few pictures taken during the event

Me doing the presentation of our hack

Salai helping me with the screens

Our prize, a Kindle Paper White each and some certificates :)

Friday, May 15, 2015

[IDEA] Autoscaling in Hadoop

Everybody today uses Hadoop + some more of its ecosystem tools. Let it be Hive / HBase etc. I have been using Hadoop for writing production code from 2012 and for experiments much earlier than that. One thing that I don't see it anywhere is the ability to autoscale the Hadoop cluster elastically. Unlike scaling web servers having all map and reduce tasks full doesn't necessarily translate to CPU / IO metrics spiking on the machines.

Figure - Usage graph observed from a production cluster
hand drawn on white-board

On this front - Only Qubole guys have seem to have done some decent work. You should check out their platform if you haven't. It is really super cool. A lot of inspiration for this post have been from using them.

This is one of my hobby project attempt at building just the Autoscaling feature for Hadoop1 clusters if had been part of say Qubole team back in 2012.

In this blog post I talk about the implementation goals and/or hows building this as part of InMobi's HackDay 2015 (if I get through the selection) or go ahead and build it anyways on that weekend.

For every cluster you would need the following configuration settings

minNodes - Minimum # of TTs you would always want in the cluster.
maxNodes - Maximum # of TTs that your cluster would like to use at any point in time.
checkInterval - Time unit in seconds to check the cluster for compute demand (default - 60)
hustlePeriod - Time unit in seconds to monitor the demand before we go ahead with upscaling / downscaling the cluster. - (default - 600)
upscaleBurstRate - Rate at which you want to upscale based on the demand (default- 100%)
downscaleBurstRate - Rate at which you want to downscale (default - 25%)
mapsPerNode - # of map slots per TT (default - based on the machine type)
reducersPerNode - # of reduce slots per TT (default - based on the machine type)

Assumptions
- All the nodes in the cluster are of same type and imageId - easier during upscaling / downscaling.
- All TTs will have Datanodes also along with it

Broad Goals

- Less / No manual intervention at all - We're talking about hands-free scaling and not one click scaling.

- Should have less / no changes in the framework - If we start making forks of Hadoop1 / Hadoop2 to support certain features for autoscaling then most likely we'll have a version lock which is not a pretty thing 1-2 years down the lane.

- Should be configurable - For users willing to dive deeper for configuring their autoscaling they should have options to do that. Roughly translates to being all blue configurations having sensible defaults.

Larger vision is to see if we can make the entire thing modular enough to support any type of scaling.

Please do share your thoughts if you have any on the subject.

Monday, February 2, 2015

GoCD - Slack Build Notifier

In my last post I wrote about a GoCD plugin that I've been working on. I finally got to complete it this weekend. Check it out https://github.com/ashwanthkumar/gocd-slack-build-notifier. This is how the final result looks like

There are two features in the plugin that I'm really happy about (apart from pushing messages to slack)

Pipeline rules set. It is heavily inspired from the current email notification framework available as part of GoCD. Check out the "Pipeline Rules" section in README.
Notifier is pluggable. Slack Notifier is provided out of the box. With very little change, one can write any type of notifications transport using the existing framework.

Overall it was a time well spent that helped me to write (which I guess is) first notification plugin in the GoCD community.

Monday, August 13, 2012

Physique - Marrying Physics and Social Computing

Consider a world, where in "living" beings aren't the only "living" entities anymore. Things considered impossible / immovable started freely communicating with each other. I guess right now "The Matrix" should have crossed your mind if you are by any chance a tech bluff like me.

That is exactly what I always wanted to see / build in my real life, not just in movies. Now at Yahoo! Open Hack 2012 (5th Edition at India), these guys provided a problem statement - under "Digital Communication"

Your challenge is to build a product or feature that solves a problem in the digital communications space. Think about how you can add to the existing communications landscape. Your solution may be mass market, or specific to a particular segment of the marketplace, like development teams for example. Where appropriate, use Yahoo! Mail or Messenger APIs to add value to your hack.

Source - http://openhackindia2012.hacker.yahoo.net/#discussions/49989

And reading, a lot of articles (including this on Techcrunch published < 24 hours ago, during the hackathon), news, and personally watching lot of changes and trends in the market myself I am completely convinced that I there is lot of scope in "Digital Communication" space.

I checkout my Facebook and Twitter Feeds often, but when you are part of a gathering of this size, 1 in every 3 - 5 machines has either Twitter / Facebook open ALWAYS. I realized that Social Networking has just become so much part of our lives.

Thinking all these into my mind, allow me to introduce - "Physique". Something we were able to develop in ~30 hours, hoping to change the way "Machines" communicate and collaborate in the future, for Humans.

Physique is all about everyday things sharing their current state information with you in real time. Imagine if all the things you own had a digital identity (say, like a Facebook Profile) and shared their information continuously with you like your social media friends do. That is what Physique aims to be!

We call all physical objects as "Thngs" (yes intentionally) and provide a API to access them. Basically, you build apps on top of our platform for the objects to connect with each other and enable collaboration among them.

Some high-level example Use-Cases (something which will be reality in < 50 years from now)

Your fridge can order Milk cartons for you, when you are running out of milk.
Your Television will record certain segments of the telecast, when you get a call and you ought to attend it.
Wine glasses in a party can help bring like-minded people together, same wine glasses can also pre-order condoms for you if there need be.

... Etc. to name a few

Well, I think you get the picture by now, regarding what I said by "communication + collaboration" of machines. In order for all these things to happen, there has to be some established standards and protocols, for the devices to communicate and make things happen.

We have a basic version of the hack up and running at http://labs.ashwanthkumar.in/physique/ (we are still working on the API Documentation + SDKs for developers).

We will come back to you with more updates and features in the up coming weeks. In the meantime if you have any ideas, or if you are working on something similar we would love to connect with you :-)

Sunday, July 22, 2012

Tweetoem - Discovering Art in Tweets

Title is slightly mis-leading, but I cannot think of a better way to put it. Let me tell you the story behind building of "Tweetoem" (Tweets + Poem).

Just in case you stumbled on this post first, Tweetoem is live on http://labs.ashwanthkumar.in/tweetoem/

Tweetoem is highly inspired from 140verses (http://140verses.com/). One of my friends shared this link (he is one of the developer of 140verses) on his facebook timeline. It was love at first sight for me, when my reverse-engineering brain cells got activated. I looked into the tweet generating poems, I loved the idea, I loved the execution of work. It has been quite some time until I did any hacks (none after I started working, life of intern seems a bliss now). So to put my spirits high and to brush up on my PHP skills I wondered if I can put something like that in < 6 hours of work? And "Tweetoem" was the result of that work.

Algorithm (working behind the scenes)

Get the tweets from Twitter
Strip user_mentions, hashtags, and links of the tweets
Get the last word and reverse it
Calculate the Metaphone value of that word
Store the Tweet + Metaphone value

I am not sure if this is exactly what is being used (from my observation, it seems to be something more sophisticated), but this seems to do the trick for me. I got a bootstrap template, wrote a couple of controller methods (limonade kicks ass here), and that's it. What you see is the outcome of that work in ~6 hours of hacking.

Known Issues

System is relatively new, so you might not get poems at many chances
Sometimes the lines might be repeated in the poem
Occasionally search breaks for no reason, little refresh or a new keyword should do the trick
No Share features like in 140verses (intentionally not implemented)

Disclaimer - Tweetom idea was inspired from 140verses and the original developers are to be highly appreciated for the innovative thinking + work. Tweetoem was just a self ego satisfying bad hack to replicate the same in less than a day. It is by no means tries to compete with 140verses / their scope.

Monday, March 19, 2012

Fixing RHIPE socketConnection Error

Today I was working with RHIPE, testing another tool for working with R and Hadoop. When I installed the ProtoBuf 2.4.1 and RHIPE 0.66 and tried to run the test sample, I had the socketConnection problem while Rhipe library was trying to connect with the server that was started.

After some debugging I found out that, since I did not have localhost entry in my /etc/hosts but some custom mappings as per my env settings. Diving into R code I figured out that Line 25 points at "localhost" and all I had to do was to change it to 127.0.0.1 and re-install the Rhipe library.

I forked the project and modified it the code on https://github.com/ashwanthkumar/RHIPE. Need to give him a pull request after looking further into the code.

Saturday, February 25, 2012

Hadoop AutoKill Hack

February's Hack! As you might have already known that I am working on Big Data, and by De facto we all use Hadoop eco-system to get things done. On the same page, I was just looking into some Hadoop Java API the other day to see how well I can get to see somethings happening under the hood.

More specifically I was trying to use JobClient class to see if I can build some custom client or an interface to the Hadoop Jobs we run on our cluster. During which I thought, can I add custom Job Timeout feature to Hadoop.

Problem Statement: I want to kill any job that runs beyond T time units in Hadoop and how do I do it?

So I started writing custom client which can interact with the JobTracker to get the list of running jobs, and how long they have been running. If they exceed my given threshold time limit I would want to kill them. That is the overall concept, and I guess what I built it. API is so simple and straight forward, all it took was less than an hour to look into the jobdetails.jsp and see how to access the Jobs from the JobTracker and display the start time.

However the tricky thing was how to run the damn thing. I always got the "IOException: Broken Pipe" error. Then finally got the way we need to access it, was through running it as

$ hadoop jar JARName.jar

So, yeah I wrote a small hack for this. You can find it on my Git (https://github.com/ashwanthkumar/hadoop-autokill).

Thursday, February 9, 2012

Introducing Scraphp - Web Crawler in PHP

Scraphp (say Scraph, last p is silent) is a web crawling program. It is basically built to be a standalone executable which can crawl websites and store extract useful content out of it. I created this script for a challenge posted by Indix on Jan 2012, where in I was asked to crawl AGMarket (http://agmarknet.nic.in/) to get the prices of all the products, and store their prices. I also had to version the prices such that it should persist across dates.

Scraph was inspired from a similar project called Scrappy, written in Python. This is not an attempt to port it, but just wanted to see how much similar properties can I build from it in less than a day.

One of the major features I would like to call it is, When you crawl the page you can extract entites out of it based on XPath. So basically when we crawl a page I create a bean whose properties are set of values got by applying the given XPath on the page. Each XPath is completely independent of the other. Currently Scraph supports creating only 1 type of object per page.

Hack into the source code, its well commented and easy to modify as per requirement. All the details of the crawling page, XPath queries are all provided in the configuration.php or you can supply your own config file, see the Usage.

Code is available on my Git Repo - https://github.com/ashwanthkumar/scraphp

I have tired my best to document the entire code well, and if you feel like any improvements can be made or you have got any suggestions? Please do not hesitate to fork and send me a pull request.

Monday, January 2, 2012

NSE Valid Symbols

List of NSE Symbols for reference for NSE Live Stock API (http://live-nse.herokuapp.com/?symbol=INFY)

Above is the list of Valid NSE Symbols snapshot fetched at 2nd Jan, 2012 from http://goo.gl/jz7NY

PS: This information is shared with a motive it might be useful, and nothing else.