TUTYSARA'S SPACE

Clean Code vs A Philosophy of Software Design

Sat, 14 Feb 2026 00:00:00 +0000

Reading through many lines of code in Golang and Java makes for an interesting observation from the codebase which I was taking a look.

There were different styles of coding and it was obvious from reading code that is written by experienced gophers.

People on team who do both Java and Golang use the same Java style in Golang as well.

While most Java programmers come from Clean code school of thought where functions are decomposed into many smaller functions which results in function explosion in the same file.

SQS vs SNS vs Kinesis

Tue, 07 Sep 2021 00:00:00 +0000

Service	Think of it as
SQS	A durable queue between producers and consumers
SNS	A fan-out notification system
Kinesis	A high-throughput event stream

SQS:

Is ideal when

Producers and consumers run at different speeds
You want retry, durability, and backpressure
Each message should be processed at least once

SNS

SNS is about fan-out, not durability for processing.

Push-based
One message → many subscribers

Subscribers can be: SQS queues or HTTP endpoints or Lambda

Implement mutex using channels

Fri, 05 Jul 2019 00:00:00 +0000

Concurrency primitives can be implemented on top of channel abstraction of CSP style. Here is an example of implementing mutex using channels.

Go code to implement mutex using channels.

package main

import "fmt"

type Lock struct {
	locked chan bool
}

func NewLock() Lock {
	lock := Lock{locked: make(chan bool, 1)}
	lock.locked <- true
	return lock
}

func (l *Lock) Lock() {
	<-l.locked // read from channel and if another read happens it waits
}

func (l *Lock) Unlock() {
	// This is not reentrant

	// calling unlock again on an unlocked channel blocks
	l.locked <- true // write to channel so, that it gets read and channel clears
}

This is not reentrant

Tips to prepare for TOEFL in two weeks

Thu, 05 Apr 2018 00:00:00 +0000

I wanted to share some tips on quickly preparing for the TOEFL iBT test
I had to take TOEFL on a short notice, I had two weeks to take the exam and had prepared using materials that I will share in this post
It helped me get a decent score (106/120) and I wanted to share those incredible materials that helped me with everyone who are looking to ace the exam in a short span of time.

Machine Learning Flashcards from Twitter -- Part 2 Data Analysis and Download

Sun, 11 Feb 2018 00:00:00 +0000

This is the analysis part where we do a small analysis to find

Which are the most important/popular tweets
Whether older materials covered important concepts than recent tweets

Load the necessary libs

%load_ext autoreload
%autoreload 2
%matplotlib inline


import pandas as pd
pd.set_option("display.width", 150)
import requests
import re
import matplotlib.pyplot as plt
import matplotlib.image as mpimg
from pathlib import Path

Load csv

df = pd.read_csv("chrisalbon_mlflashcards.csv")
df['text'].fillna('', inplace=True)

df.tail()

 id likes replies retweets text timestamp url img_url
236 94607825069... 19 1 0 Bayes Error 2017-12-27T... https://twi... https://pbs...
237 94575108497... 47 3 13 Occams Razor 2017-12-26T... https://twi... https://pbs...
238 94571793723... 8 0 1 K-Fold Cros... 2017-12-26T... https://twi... https://pbs...
239 94538342129... 18 1 1 Extrema 2017-12-25T... https://twi... https://pbs...
240 94536381783... 34 1 7 Softmax Act... 2017-12-25T... https://twi... https://pbs...

Check for missing values

df.count(axis=0)

id 241
likes 241
replies 241
retweets 241
text 241
timestamp 241
url 241
img_url 237
dtype: int64

We see we have few img_urls missing. Let’s check what they are

Machine Learning Flashcards from Twitter -- Part 1 Data Collection and Preprocessing

Fri, 09 Feb 2018 00:00:00 +0000

I was searching the net for mlflashcards, I found this incredible machine learning flashcard tweet series from Chris Albon. It looks pretty and covers a lot of ground, Got a thought – why not download them for later use? I thought it would be a fun exercise to start the weekend and jumped into action.

Step 1 – Collect/Scrape data from twitter

I evaluated using twitter api using tweetpy, but it has its own limitation aka we can search only a week worth of data which is not good for our use case. We shoud be able to get data spread across months since the tweets we are interested are spread across a wide time range.

Themes and Extensions for Jupyter notebook

Wed, 07 Feb 2018 00:00:00 +0000

I am taking the wonderful fast.ai course thought by Jermey Howard and Rachel. We use jupyter notebooks in classes and it is always nice to see how Jermey’s notebook looks.

It has few tweaks like

collapsible headings
better tables and fonts

Learnt that he uses a themes for the visual customizations and an extensions to allow collapsing of headers from his reply in forums

The theme script can be installed from jupyter-themes repo

Use Skipgrams with sklearn CountVectorizer and TfidfVectorizer

Sun, 07 Jan 2018 00:00:00 +0000

We don’t have an implementation for skipgrams in sklearn. This post covers how to use the skipgram function in nltk with sklearn’s CountVectorizer and TfidfVectorizer

We are going to create a skipgram tokenizer that can be passed to the tokenizer parameter of the vectorizer.

Create a basic tokenizer that can split the original strings to tokesn. Tokenizer can be just .split() or a function to filter non-alpahbets etc. We can use tokenizer as below

Fix isset error in Hugo 2 version

Sun, 26 Mar 2017 19:17:21 +0530

I have setup automatic compiling and deploying of my blog using Travis.CI

Recently I encountered a strange issue, the blog compiles and runs fine in my system but the site doesn’t come up after a Travis build.

On investigation found this in the logs from Travis CI.

Deploying updates to GitHub...
Started building sites ...
ERROR 2017/03/25 02:31:30 .Page's Use RSSlink is deprecated and will be removed in Hugo 0.21. RSSLink.
ERROR 2017/03/25 02:31:30 partials/homepage.html template: partials/homepage.html:3:10: executing "partials/homepage.html" at <isset .Site.Params.s...>: error calling isset: unsupported type "invalid"

My local hugo from homebrew was v0.19 and the installation in Travis uses the latest hugo build

Spacemacs Ctrl-i fix

Fri, 24 Mar 2017 09:07:41 +0530

Spacemacs uses Ctlr+o to move backward to the last edited location and Ctrl+i to move foward after going back using Ctrl+o similar to Vim.

I found that Ctrl+o works but Ctrl+i doesn’t moves forward through the edit locations. I had the same issue in OSX/emacs 25.1 and in ubuntu/emacs25.1.

Searched the net and found this helpful issue page – https://github.com/syl20bnr/spacemacs/issues/5050

We have the troubleshooting steps there

(lookup-key evil-motion-state-map [C-i]) ;; should be evil-jump-forward
(display-graphic-p) ;; should be t
dotspacemacs-distinguish-gui-tab ;; should be t
(lookup-key key-translation-map [?\C-i]) ;; should be spacemacs/translate-C-i

In my system dotspacemacs/user-configcemacs-distinguish-gui-tab is set as nil.

How to create custom profile ID in googleplus

Thu, 29 Sep 2016 04:30:51 +0530

I was writing my blog and added a link to google plus in the sidebar. I wanted to make a human readable/rememberable Id to use for my google plus page.

I guess, planning to {use|add link} to google plus is a bad idea. I googled to find the steps to create a custom profile Id and landed in the documentation page – Get a custom URL for your Google+ profile

I tried following the steps and surprisingly it didn’t worked, I trusted google so much that I thought I may have did some mistake and repeated the steps one more time but still it didn’t worked.

Automating hugo blog deployment to github pages using travis-ci

Tue, 27 Sep 2016 03:35:35 +0530

Here are the steps I took to build and deploy my blog automatically using hugo and travis-ci to github pages

I assume a hugo blog is already created and exist

Create .travis.yml file in the project directory with the following contents

 language: go
 sudo: required
 git:
 submodules: true
 install:
 - go get -v github.com/spf13/hugo
 script: bash ./deploy.sh
 notifications:
 email:
 on_failure: always

Generate and encrypt github token

Good Font for Spacemacs

Sat, 03 Sep 2016 14:25:00 +0000

Spacemacs recommends using source code pro as the default font, infact this is the font set in .spacemacs file. If the font is not availale it is substituted for some other alternative. To find the font in use do C-u C-x = on my mac it was using Menlo font. DejavuSansMono looks better than Source code Pro on ubuntu and I switched to it in my ubuntu system. A list of top programming fonts can be found at Top programming fonts

Django development on OSX using emacs

Wed, 30 Oct 2013 13:16:00 +0000

I started following the Django tutorials by arun. I wanted to know about the related classes and quickly look into docs for the things that I code, I wanted an environment that is nice to newbies, helping with code completion and easy documentation lookup. I searched and found a huge list of options. Since I was begining with Django I wanted an environment that is much easier to setup, my first choice was pycharm, but unfortunately the community edition of pycharm doesn’t support Django - see this.

Running a Hacker news clone

Mon, 21 Oct 2013 15:25:00 +0000

I very much like the presentation of hackernews when it comes to understanding and making sense of the discussions quickly. It is a lot easier than reading pages of forums to get the main ideas of the discussions since the top comments and active discussions bubble to the top.

I wanted to run a site for discussing and sharing information that are useful for people working in techparks and the format that immediately clicked in my mind was the hacknews style. I began writing my own clone based on the work of people from hackerschool but it lacked the polish and look to make the people trust and even sign up, I had send invites to few of my friends to try but the turnaround rate was quite low.

Setting up a new VPS server

Fri, 18 Oct 2013 11:16:00 +0000

These are the things I did to setup new VPS instances on Digital Ocean and ChicagoVPS

Update the machine

sudo apt-get update
sudo apt-get upgrade

Set locales

sudo locale-gen
sudo dpkg-reconfigure locales

add user

sudo adduser tutysra
# give sudo previliges
sudo visudo
tutysra ALL=(ALL) ALL

Install Git

sudo apt-get install git

Install sun java

sudo add-apt-repository ppa:webupd8team/java
sudo apt-get update
sudo apt-get install oracle-java7-installer

Install Tor for screen scrapping

sudo apt-get install tor
sudo /etc/init.d/tor start

Make default directories

mkdir ~/swt
mkdir ~/bin

Install NX ( not necessary for CLI boxes)

export DEBIAN_FRONTEND=noninteractive
sudo -E apt-get update
sudo -E apt-get install -y ubuntu-desktop
sudo apt-get install gnome-session-fallback

wget 'http://64.34.173.142/download/3.5.0/Linux/nxclient_3.5.0-7_amd64.deb'
wget 'http://64.34.173.142/download/3.5.0/Linux/nxnode_3.5.0-9_amd64.deb'
wget 'http://64.34.173.142/download/3.5.0/Linux/FE/nxserver_3.5.0-11_amd64.deb'

sudo dpkg -i *.deb
sudo /usr/NX/bin/nxserver --status

nano /usr/NX/etc/node.cfg
# Uncomment the “DefaultXSession” line and set it to :
DefaultXSession=/etc/X11/Xsession

Enable/Disable password authentication in ssh

sudo vi /etc/ssh/sshd_config
 PasswordAuthentication to "yes/no" 
 PermitRootLogin no
sudo service ssh restart

Install screen & tmux

sudo apt-get install screen
sudo apt-get install tmux

Install curl

sudo apt-get install curl

Install emacs and customize

sudo apt-get install software-properties-common # installs some python scripts necessary for these operations
sudo add-apt-repository ppa:cassou/emacs
sudo apt-get update
sudo apt-get install emacs-snapshot-el emacs-snapshot-gtk emacs-snapshot
export TERM=xterm-256color

Install lein

mkdir ~/bin && cd ~/bin
wget 'https://raw.github.com/technomancy/leiningen/stable/bin/lein'

Install JDK6 for neo4j

wget --no-cookies --header "Cookie: gpw_e24=http%3A%2F%2Fwww.oracle.com" http://download.oracle.com/otn-pub/java/jdk/6u41-b02/jdk-6u41-linux-x64.bin 

export JAVA_HOME=/home/neo4j/swt/jdk1.6/
export PATH=/home/neo4j/swt/jdk1.6/bin:$PATH

Configure swap

My ChicagoVPS runs on OpenVZ and Swap space couldn’t be enabled at VM level.

Correlation between INR values of different currencies

Fri, 05 Oct 2012 11:16:00 +0000

Correlation between INR values of different currencies 2012-09-05 11:31 data clojure

This is an interesting take away example from the class which Anand is teaching at NIAS. Here we are trying to correlate between the INR values of various currencies like AUD, CNY (Chinese Yen), EUR, GBP (Great Britain Pound), JPY, SGD, USD and find the positive or negative correlations. The focus is on data collection and transformation.

The first part is the identification of a proper source to get the data. oanda.com is one such source from which historic currency exchange rates can be obtained.

Started blogging from a new place

Sun, 02 Sep 2012 16:14:00 +0000

I have been thinking about having a professional looking blog/space for some time. I noticed many people I follow on github maintaining a neat blog, I see that many of them use jekyll / octopress and use github pages for hosting. I like the concept of static blogging and wanted to give it a try.

I gone through the process and it looks neat and clean, create a github repo with your username and drop html pages into it and github takes care of serving them, damm simple. Can't wait to write my blog and here comes the first posts. I will be tweaking my comments setup with disqus and analytics and also my blog engine using this post.

About

Mon, 01 Jan 0001 00:00:00 +0000

I am Saravana, a programmer doing entreprise software by day and hacking on interesting stuff by night. I Love to try new things and experiment with various technologies/things that interests me. I usually find that my interest keeps changing and centered mostly around making things easy for me.

Contact

Mon, 01 Jan 0001 00:00:00 +0000

tutysara -> at -> g mail. com