My Internship at Josh

It was during our sixth-semester, that the entire class received an email about the internship at Josh Software Pvt Ltd. We had to attend a coding round, and then two technical rounds followed by an HR round. Being a student of Industrial mathematics course I was not into programming much but still, I decided to appear for the coding round. Overall 40 students came for the internship drive. After the initial round due to some glitch, my name was not in the list of those selected for the next round. This was a major blow to me because I was hoping to make it to the next rounds. As I was about to leave the place with a heavy heart I was informed that I have also cleared the first round. I was literally on cloud nine by this time(So overwhelmed…that I almost shouted at my friend). Then came the technical and HR rounds, I excelled in all of them and ultimately bagged my first ever internship. When I look back the whole selection process itself was a learning experience. I got to know more about myself, my goals, strengths, and weaknesses. The fact that I was the only student from my class and the only female candidate who was awarded the internship helped in firmly establishing my belief in myself.

After joining as an intern at Josh, I went through a rigorous 10 days training. I learned and relearned a lot of stuff. It was exhausting and scary at the same time. The feeling of vulnerability and inadequacy would come now and then. One thing which helped me initially in gelling out with the people at Josh was the new year’s party.

My first office party!!

All the interns were introduced to the other team members at Josh. The environment at the party was very chill. From co-founders to new appointees everyone was present there and was enjoying freely. This was an ice-breaking moment for me because I realized that your work is all that matters. As long as you are doing your work sincerely, you don’t need to be scared of anyone. It doesn’t matter whether you are experienced or fresher. Also being an intern all I wanted was an environment where there is room for mistakes, improvements and a place where people are approachable. One thing which standout for Josh is its amazing work culture. It’s so conducive for one’s overall growth.

After a while, I was assigned a project manager and a mentor. I was very nervous and especially when I and my partner were called by our project manager Anil Kumar and mentor Rahul Ojha. We were asked to complete an assignment which was full of technical jargon. Being a naive programmer I was scared to death when I was asked for this. I requested them that I need time because I have never attempted such an assignment before. To my surprise, they understood and told me to start with elementary assignments. It took a lot of mistakes, learning and brainstorming sessions with Rahul but ultimately I was able to complete my assignment. This was a huge achievement for me. The way I was being monitored by my mentor was amazing. He was not just spoon feeding but was giving me hints about what to learn and where to look for the answers. It was like a puzzle. I enjoyed it thoroughly.
The first project was finally given to me and my partner after carefully analyzing our performances. We were working on the rails technology and were asked to make an app. From being a student to an intern to my first client meeting. It was a roller coaster ride. I got a chance to directly communicate with the client. It was a humbling experience. For the first time, I felt like I am an integral part of Josh and have been given responsibilities for which I am accountable.

Presently my project is at the fag end of completion. I would be lying if I say it was an easy journey from beginning to this end. There were many ups and downs. Often I found myself in the position where I couldn’t decide how to go about the problem. When one is not able to even pinpoint the problem, finding the solution is a different problem altogether to solve. But then a word with Anil or others would dissipate the clouds of dismay. Things became easier for us because we could ask our doubts to anyone and everyone was ready to help us with full enthusiasm.

I could mention so many incidents where I was helped by my team like the one time I was frustrated with the pace at which I was completing my work. This was hampering my performance also. I was like what I am even doing here. This is not for mathematics students and is tailor-made for computer science students. Like a cold breeze on a hot day, Rahul’s advice would come to stick with the problem and that with extra effort I could solve my problem. God and only he knows how much I have troubled him by my doubts. Shailesh for whom I had this impression that he is very reserved and strict proved me wrong by laughing at the memes I used to show him. The attitude of Ganesh whenever he sees a problem often leaves me speechless. His statement “ab to isko solve karenge hi” works like glucose. It provides immense energy to tackle any problem. Sahil’s perseverant attitude always pushed me to have the same tenacity on my work too. I still remember one talk delivered by Mr. Gautam Rege(Co-founder of Josh), it was accessible to anyone and was very motivating. All one needs at the start of his career is ample support and motivation. I really look up to you sir. Thank you for being so inspiring and motivating.

As I have mentioned earlier, the one thing which standout at Josh is its work culture. It’s a perfect blend of professionalism and flexibility. One gets appreciated for good work and at the same time, you can’t take your work for granted. I remember the numerous times I have been rebuked for my mistakes and also appreciated for my good work. My participation as a trainer during one of Rails girls meet up was appreciated in All hands. These little acts worked as a catalyst for my growth.

How many times does an intern get the chance to share lunch with co-founders? Yes, not many times but at Josh, the environment is very congenial. The monotonous office culture would sometimes take a toll on us and to kill the boredom we-the music lovers-would start playing songs. Instead of not allowing us Neha and Sai would just advice us to slightly lower the volume. The other thing which came to our rescue was carrom. I am nowhere qualified even to tell myself a naive player. The probability that I would not hit the piece I am targeting was more than I hit it. I was casually made fun of my bad shots by Mr. Umesh and Mr.Swapnil but now it seems that along with programming skills, I have also honed up my carrom skills.
This blog has been the hardest to write for me by far. In part, the challenge stems from trying to sum up months worth of experiences in just a few paragraphs.
My internship at Josh software has taught me more than I could have imagined. As an Intern, I feel my duties were diverse and ever-changing. Sometimes it’s tough to recall everything I have taken in over the past months, but I feel that these are some of the most beneficial lessons I have learned.

What I’ve Learned:

I’m not alone: Coming into this position, I felt that I had no idea where my career was going and I lacked confidence about what I could do and what I am really good at. My internship has definitely given me a better understanding of my skill set and where my career may take me, but most importantly, I’ve come to learn that I am not alone. This job has taught me that almost everybody is in the same position. Very few college students know what they want to do, and it is something that is simply not worth worrying about. Thanks to my internship I now know that if I continue to work hard things will fall into place.

How to behave in the office: This being my first position in an office atmosphere, I didn’t know exactly what to expect. The environment here at Josh is quite relaxed, yet it taught me how to behave in the workplace. Simply working in the office and getting used to everything here has definitely prepared me for whatever my next position may be. Just observing the everyday events has taught me more about teamwork, and how people can come together to get things done. Although sometimes I have to remind myself to use my inside voice, I feel I’ve adapted to office life relatively well.

How to build my resume: As I said, this internship has improved my skills a ton, both off the paper and on paper. I didn’t realize it all of this time, but this position served not only as a positive learning experience but a resume builder as well. I came into this with a resume that was basically naked, now I am leaving and I have lots of updating to do. My resume doesn’t need a makeover, it needs to be restarted from scratch, and that’s a good thing! I underestimated how much work I did that actually translates to my resume.

I’d like to thank everyone here at Josh who has helped me out. This has truly been a great learning experience and I’ll be forever indebted to those who gave me a hand here. As far as future interns are concerned I would advice to always be friendly, work hard, and ask questions. Always ask questions. Hopefully, you come away from your internship with as much as I did.

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GoLang with Rails

Content posted here with the permission of the author Shweta Kale who is currently employed at Josh Software. Original post available here.

GoLang with Rails? Wondering why one would use GoLang with Rails?

Read on to find out!!

This is purely based on our requirement but can surely benefit others looking forward to similar use-case. We had a web app written in Rails but facing performance bottleneck while processing large chunk of data. The natural choice seem to use power of GoLang concurrency.

In order to use GoLang with our Rails app few approaches came to my mind. But I found one or the other flaw:

  • Write api’s in GoLang APP and route request from nginx based on request URL. Simple but for using this approach we would also need to add authentication in GoLang app. So authentication will be Rails as well as in GoLang – This doesn’t seem correct, because if I had to change authentication mechanism, would need to make changes in two apps.

  • Use RestClient and call GoLang apis from Rails application. So request will be routed to Rails app and it will call api from GoLang app and serve response. Here I will achieve some level of performance but again my Rails app will have to serve request which GoLang app can directly serve and the response has to wait for response from GoLang app.

  • Use FFI. Using FFI we can call GoLang binary directly. You can watch this video to see how it can be done. This seems fine at first, but what if I had to load balance moving GoLang app to other server?

So which approach did I follow?

We went with NONE of the above, but a 4th idea using rack_proxy gem.

Here is sample code for middleware we wrote

class EventServiceProxy < Rack::Proxy
def initialize(app)
@app = app

def call(env)
original_host = env["HTTP_HOST"]
if env["HTTP_HOST"] != original_host

def rewrite_env(env)
request =

if request.path.match('/events')
if env['warden'].authenticated?
env["HTTP_HOST"] = "localhost:8000"
env['HTTP_AUTHORIZATION'] = env['rack.session']['warden.user.user.key'][0]


And we inserted our middleware just after Warden (Devise uses this internally for authentication)

config.middleware.insert_after(Warden::Manager, EventServiceProxy)

In above code snippet we are just proxing our request to localhost:8000 where GoLang App is running and setting up user_id in header. Warden adds authenticated user_id in env['rack.session']['warden.user.user.key'][0] so now we know who is logged in at GoLang App from header.

We added middleware in GoLang which extracts user_id from header and sets curretUser details in context.

Important Note
Our GoLang application is exposed only to Rails application and not to the whole world so we are sending user_id in header.

The main advantages we saw using this approach are:

  • We could use existing authentication mechanism used in Rails application
  • If needed we can add load balancer to our Rails and/or GoLang application which is micro service.
  • If we have used FFI we had to put binary on same machine but here we can have application and GoLang service on different machines.
  • As request will be rewritten from Rack it saved redirect and going through entire stack of rails app.

This could be used with any framework similar to Rails.

By using above approach now we can use power of GoLang when needed and development speed of Rails 🙂

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Deploying Service Based Architecture Application on Amazon’s ECS (Elastic Container Service)

Content posted here with the permission of the author Anil Kumar Maurya, who is currently employed at Josh Software. Original post available here.

This blog is second part of Post .

If you have not already read it then I recommend going through it first, I have explained why we chose Service Based Architecture and how Docker helped us in setting up & starting application on local machine with just one command.

In this post we will see how to deploy our App on multiple docker container using Amazon’s ECS.

Why deploy container for each service

Deploying all service on single machine is possible but we should refrain from it. If we deploy all service on single machine then we are not utilising benefits of service based architecture (except manageable/easy-to-upgrade codebase).

2 Major benefits of container deployment for each service are:

  1. Isolation of Crash
  2. Independent Scaling

Isolation of Crash:

If one service in your application is crashing, then only that part of your application goes down. The rest of your application continues to work properly.

Independent Scaling:

Amount of infrastructure and number of instances of each service can be scaled up and down independently.

Why we chose Amazon’s ECS

We mostly use Amazon’s AWS service for deploying our applications therefore our first preference is services provided by Amazon AWS for deploying containers.

For container deployment, Amazon provide 2 service to choose from

  1. EKS (Elastic Container Service for Kubernetes)
  2. ECS (Elastic Container Service)

Amazon is charging $0.2 per hour for each Amazon’s EKS cluster. We didn’t wanted to pay for services which is not directly impacting our business therefore we looked for alternatives.

Amazon does not charge for ECS. We have to pay only for the EC2 instance which are running. Another advantage of ECS is its learning curve which is much lower then EKS.

Therefore ECS is optimal for our use case.

Before we start using ECS, we should be familiar with components of ECS

Components of ECS

  • Task Definition
  • Task
  • Service
  • Cluster
  • ECR

Task Definition:

task definition is like a blueprint for your application. In this step, you will specify a task definition so Amazon ECS knows which Docker image to use for containers, how many containers to use in the task, and the resource allocation for each container.


Task is instance of a Task Definition. It is running container with the settings defined in the Task Definition


A service launches and maintains copies of the task definition in your cluster. For example, by running an application as a service, Amazon ECS will auto-recover any stopped tasks and maintain the number of copies you specify.


A logic group of EC2 instances. When an instance launches the ecs-agent software on the server registers the instance to an ECS Cluster.


Amazon Elastic Container Registry (ECR) is a fully-managed Docker container registry that makes it easy for developers to store, manage, and deploy Docker container images. Amazon ECR hosts your images in a highly available and scalable architecture, allowing you to reliably deploy containers for your applications.

Launch Types:

Amazon ECS has two modes: Fargate launch type and EC2 launch type

  • Fargate
  • EC2


AWS Fargate is a compute engine for Amazon ECS that allows you to run containers without having to manage servers or clusters. With AWS Fargate, you no longer have to provision, configure, and scale clusters of virtual machines to run containers. All you have to do is package your application in containers, specify the CPU and memory requirements, define networking and IAM policies, and launch the application


EC2 launch type allows you to have server-level, more granular control over the infrastructure that runs your container applications. Amazon ECS keeps track of all the CPU, memory and other resources in your cluster, and also finds the best server for a container to run on based on your specified resource requirements. You are responsible for provisioning, patching, and scaling clusters of servers. You can decide which type of server to use, which applications and how many containers to run in a cluster to optimize utilization.

Choosing between Fargate & EC2

Fargate is more expensive than running and operating an EC2 instance yourself. Fargate price is reduced by 50% recently . To start with, we need more control over our infrastructure therefore we chose EC2 over Fargate. May be we will switch to Fargate in future when its cost is similar to EC2 and we have more experience in managing ECS infrastructure.

Create ECS Cluster

Go to Amazon ECS Service,

In few minute, your cluster will be created and you will see it under ECS service.

Traefik (Load Balance & Proxy Server)

Traefik (open source & production proven) is a modern HTTP reverse proxy and load balancer that makes deploying microservices easy. Traefik integrates with your existing infrastructure components and configures itself automatically and dynamically. Traefik listens to your service registry/orchestrator API and instantly generates the routes so your microservices are connected to the outside world.

Traefik Overview

Traefik Web UI

Traefik provides a web UI for showing all running container and path on which they are served. Example:

Traefik Web UI

Deploy Traefik on ECS

Create a Task definition for Traefik, click new task definition.

Click on Add Container.

Click Create Create Task Definition.

Now we will create a service for running Traefik task

Click on create service. This will create a service, After Service is created, it will start running a Task for given task definition.

Edit Security Group Inbound port, Add following rule:

Now go to public IP address of EC2, example:

You should see Traefik Dashboard.

Create ECR Repo for each service

Go to Amazon ECR service:


You can send each container instance’s ECS agent logs and Docker container logs to Amazon CloudWatch Logs to simplify issue diagnosis.

Edit Task definition to set log configuration

Deploying Rails API

  • Create a Task Definition for Rails API

After creating task definition, create a service to launch container

  • Service

Other steps is similar to Traefik service creation, as shown above.

traefik.frontend.rule in Docker label specify mapping for url & service. Example:;PathPrefixStrip:/rails-api, here /rails-api path is mapped with our rails-api container which is running on ECS.

Once service is live and task is running, curl and it will be served through rails-api container which we just deployed.

Deploying React APP

Deployment step for react is similar to rails app, only difference is creation of react image for production deployment.

My Dockerfile for react production deployment is:

FROM node:11.6.0-alpine

WORKDIR '/app'

# Install yarn and other dependencies via apk
RUN apk update && apk add yarn python g++ make && rm -rf /var/cache/apk/*

COPY package.json yarn.lock /app/

COPY . ./

RUN npm run build

# production environment
FROM nginx:1.13.9-alpine
ARG app_name
RUN rm -rf /etc/nginx/conf.d
COPY conf /etc/nginx
COPY --from=0 /app/build /usr/share/nginx/html/$app_name
CMD ["nginx", "-g", "daemon off;"]

conf is directory with following structure

     --- default.conf

default.conf contains

server {
  listen 80;
  root   /usr/share/nginx/html;
  index  index.html;
  location /react-web {
    try_files $uri $uri/ /react-web/index.html;
  error_page   500 502 503 504  /50x.html;
  location = /50x.html {
    root   /usr/share/nginx/html;

Here, I am serving my compiled HTML, CSS & JS through nginx.

My docker-compose-prod.yml

      context: './react-web'
      dockerfile: $PWD/Dockerfile-React-Prod
        - app_name=react-web
      - $PWD/inventory-web/:/app/
      - NODE_ENV=production

In package.json, I added:

"homepage": "/react-web"

and I added traefik frontend rule to map /react-web with react container.

Now create production image for react-web, push on ECR & deploy like traefik service. After deployment react-web should be accessible when accessed on /react-web path.

Deployment Script

I have written a shell script for deployment on ECS. My shell script requires AWS Command Line Interface (AWS CLI) & ecs-deploy.


# Login to amazon ecr
eval $(aws ecr get-login --no-include-email)

# Build production image
docker-compose -f docker-compose-prod.yml -p prod build $1

# Tag image with latest tag
docker tag prod_$1:latest path-to-ecr-repo:latest

# Push image to ECR
docker push path-to-ecr-repo:latest

# Use ecs-deploy to deploy latest image from ECR
./ecs-deploy -c cluster-name -n $1 -i path-to-ecr-repo:latest

Save above script in deploy file.

For deployment:

example: ./deploy rails-api


Learning curve for ECS is short and there is no extra cost for ECS service (charges applicable for EC2 instance only) therefore if you are getting started with container deployment on production then ECS is good fit.

In Next blog post I will write how to deploy Redis & Elasticsearch container on ECS and how to setup Network Discovery so that our Rails API container can communicate with Redis & Elasticsearch.

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Understanding Repaint and Reflow in JavaScript

Content posted here with the permission of the author Suhas More, who is currently employed at Josh Software. Original post available here.

Recently, while researching what makes React’s virtual DOM so fast, I realized how little are we aware about javascript performance. So I’m writing this article to help raise the awareness about Repaint and Reflow and JavaScript performance in general.”

Before we dig deeper, do we know how a browser works?

A picture is worth a thousand words. So, let’s have a high-level view of how a browser works!

hmm… what’s “browser engine” and “rendering engine”?

The primary job of a browser engine is to transform HTML documents and other resources of a web page into an interactive visual representation on a user’s device.

Besides “browser engine”, two other terms are in common use regarding related concepts: “layout engine” and “rendering engine”. In theory, layout and rendering (or “painting”) could be handled by separate engines. In practice, however, they are tightly coupled and rarely considered separately.

let’s understand how browsers draw a user interface on the screen.

When you hit enter on some link or URL browser make an HTTP request to that page and the corresponding server provides (often) HTML document in response. (a hell of a lot of things happen in between)

Step by step processing
  • The browser parses out the HTML source code and constructs a DOM treea data representation where every HTML tag has a corresponding node in the tree and the text chunks between tags get a text node representation too. The root node in the DOM tree is the documentElement (the tag)
  • The browser parses the CSS code, makes sense of it. The styling information cascades: the basic rules are in the User Agent stylesheets (the browser defaults), then there could be user stylesheets, author (as in author of the page) stylesheets – external, imported, inline, and finally styles that are coded into the style attributes of the HTML tags
  • Then comes the interesting part — constructing a render tree. The render tree is sort of like the DOM tree, but doesn’t match it exactly. The render tree knows about styles, so if you’re hiding a div with display: none, it won’t be represented in the render tree. Same for the other invisible elements, like head and everything in it. On the other hand, there might be DOM elements that are represented with more than one node in the render tree – like text nodes for example where every line in a needs a render node. A node in the render tree is called a frame, or a box (as in a CSS box, according to the box model). Each of these nodes has the CSS box properties – width, height, border, margin, etc
  • Once the render tree is constructed, the browser can paint (draw) the render tree nodes on the screen

Here is a snapshot of how browser draws user interface on screen.

It happens in the fraction of seconds that we don’t even notice that all this happened.

Look closely.
How browser drawing layout and trying to detect root element, siblings and it’s child element as node comes and rearranging it’s layout accordingly.

Let’s take one example

  <title>Repaint And Reflow</title>
    <strong>How's The Josh?</strong>
    <strong><b> High Sir...</b></strong>
  <div style="display: none">
    Nothing to display
    <img src="..." />

The DOM tree that represents this HTML document basically has one node for each tag and one text node for each piece of text between nodes (for simplicity let’s ignore the fact that whitespace is text nodes too) :

documentElement (html)
                [text node]
                    [text node]         
            [text node]

The render tree would be the visual part of the DOM tree. It is missing some stuff — the head and the hidden div, but it has additional nodes (aka frames, aka boxes) for the lines of text.

root (RenderView)
            line 1
        line 2
        line 3

The root node of the render tree is the frame (the box) that contains all other elements. You can think of it as being the inner part of the browser window, as this is the restricted area where the page could spread. Technically WebKit calls the root node RenderView and it corresponds to the CSS initial containing block, which is basically the viewport rectangle from the top of the page (00) to (window.innerWidthwindow.innerHeight)

Figuring out what and how exactly to display on the screen involves a recursive walk down (a flow) through the render tree.

Repaint and Reflow

There’s always at least one initial page layout together with a paint (unless, of course you prefer your pages blank :)). After that, changing the input information which was used to construct the render tree may result in one or both of these:

  1. parts of the render tree (or the whole tree) will need to be revalidated and the node dimensions recalculated. This is called a reflow, or layout, or layouting. Note that there’s at least one reflow — the initial layout of the page
  2. parts of the screen will need to be updated, either because of changes in geometric properties of a node or because of stylistic change, such as changing the background color. This screen update is called a repaint, or a redraw.

Repaints and reflows can be expensive, they can hurt the user experience, and make the UI appear sluggish

As the name suggests repaint is nothing but the repainting element on the screen as the skin of element change which affects the visibility of an element but do not affects layout.
1. Changing visibility of an element.
2. Changing outline of the element.
3. Changing background.
Would trigger a repaint.

According to Opera, the repaint is an expensive operation as it forces the browser to verify/check visibility of all other dom nodes.

Reflow means re-calculating the positions and geometries of elements in the document, for the purpose of re-rendering part or all of the document. Because reflow is a user-blocking operation in the browser, it is useful for developers to understand how to improve reflow time and also to understand the effects of various document properties (DOM depth, CSS rule efficiency, different types of style changes) on reflow time. Sometimes reflowing a single element in the document may require reflowing its parent elements and also any elements which follow it.

Virtual DOM VS Real DOM

Every time the DOM changes browser need to recalculate the CSS, do layout and repaint web page. This is what takes time in real dom.

To minimize this time Ember use key/value observation technique and Angular uses dirty checking. Using this technique they can only update changed dom node or the node which are marked as dirty in case of Angular.

If this was not the case then you are not able to see new email as soon as it comes while writing a new email in Gmail.

But, browser are becoming smart enough nowadays they are trying to shorten the time it takes to repaint the screen. The biggest thing that can be done is to minimize and batch the DOM changes that make repaints.

The strategy of reducing and baching DOM changes taken to another level of abstraction is the idea behind React’s Virtual DOM.

What makes React’s virtual DOM so fast?

React doesn’t really do anything new. It’s just a strategic move. What it does is It stores a replica of real DOM in memory. When you modify the DOM, it first applies these changes to the in-memory DOM. Then, using it’s diffing algorithm, figures out what has really changed.

Finally, it batches the changes and call applies them on real-dom in one go. Thus, minimizing the re-flow and re-paint.

Interested in reading more on that? Well, that’s a topic for another post?

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Docker Setup for Service Based Architecture Application

Content posted here with the permission of the author Anil Kumar Maurya, who is currently employed at Josh Software. Original post available here.

What is Service Based Architecture ?

At first Micro Service Architecture & Service Based Architecture looks similar but both are different from each other.

Micro service architecture advocates smaller components. An application can consist of hundred or thousands of micro services whereas Service based architecture advocates breaking the code apart in the domain-centric way. An application can consist of 10–12 deployable services. These services may have separate database or they may share same database.

Managing few micro services is easy but as number of micro services increases, challenges to manage them is not an easy task. Number of network calls also increases.

In case of Service based architecture, number of services are limited therefore managing it is not a challenge. Also number of network call is less therefore should give better performance.

ThoughtWorks director Neal Ford argued in a talk that organizations transition more easily from a monolithic architecture to a service-based architecture than to a microservices architecture


Why we chose Service Based Architecture Over Micro Services

Background: We are building an ERP Software. It is going to use by 50–100 people at a time. We are team of 3 developer and we need to deliver first release in 3 months.

We aim to build scalable and maintainable product. Monolith is out of option. We had 2 options, Micro Service OR Service Based Architecture. Micro Service requires complex setup and will double our efforts. As we have limited team size and our timelines are fixed therefore Service Based Architecture with common database made more sense for us.

Challenges we faced

We had 8 repository, one for each services. Setting up project on local for new developer is very time consuming. Every service needed to setup separately.

Apart from setting up all services. We need to install postgres, redis & elasticsearch. If you are stuck while installing any one of it then it may eat up whole day.

Also starting up application required starting all 8 services manually (which is not interesting thing to do everyday)

Docker for our rescue

We created a single repository for all services. Now getting all changes on local is just a git pull command away.

With docker, we can setup all services with all dependency with just one command.

docker-compose build

And we start our application (all services) by

docker-compose up

Setting up docker compose for an application which consist of 8 services (4 Rails-Api Backend & 4 React Frontend)

Application Directory structure looks like:


* Dockerfile is for api images
* Dockerfile-React is for react application images

Of course our services are not named as service-1 & service-2. 
I have changed it deliberately for privacy.

Our docker-compose.yml:

version: '3.6'

    image: postgres

    image: 'redis:latest'

    container_name: elasticsearch
      - bootstrap.memory_lock=true
      - "ES_JAVA_OPTS=-Xms512m -Xmx512m"
      - ""
        soft: -1
        hard: -1
      - esdata1:/usr/share/elasticsearch/data
      - 9200:9200

      context: './service-1-api'
      dockerfile: $PWD/Dockerfile
      - $PWD/service-1-api:/app
    command: bundle exec puma -p 3000
      - 3000:3000
      - db

      context: './service-1-web'
      dockerfile: $PWD/Dockerfile-React
      - $PWD/service-1-web/:/app/
      - 3001:3001
      NODE_ENV: development

      - db
      - redis
      - elasticsearch
      context: './service-2-api'
      dockerfile: $PWD/Dockerfile
    command: bundle exec sidekiq -C config/sidekiq.yml
      - $PWD/service-2-api:/app

      context: './service-2-api'
      dockerfile: $PWD/Dockerfile
      - $PWD/service-2-api:/app
    command: bundle exec puma -p 3002
      - 3002:3002
      - db
      - elasticsearch
      - service-2-sidekiq
    stdin_open: true
    tty: true

      context: './service-2-web'
      dockerfile: $PWD/Dockerfile-React
      - $PWD/service-2-web/:/app/
    command: npm start
      - 3003:3003
      - NODE_ENV=development

      - db
      - redis
      - elasticsearch
      context: './service-3-api'
      dockerfile: $PWD/Dockerfile
    command: bundle exec sidekiq -C config/sidekiq.yml
      - $PWD/service-3-api:/app

      context: './service-3-api'
      dockerfile: $PWD/Dockerfile
      - $PWD/service-3-api:/app
    command: bundle exec puma -p 3004
      - 3004:3004
      - db
      - elasticsearch
      - service-3-sidekiq
    stdin_open: true
    tty: true

      context: './service-3-web'
      dockerfile: $PWD/Dockerfile-React
      - $PWD/service-3-web/:/app/
    command: npm start
      - 3005:3005
      - NODE_ENV=development

      context: './service-4-api'
      dockerfile: $PWD/Dockerfile
      - $PWD/service-4-api:/app
    command: bundle exec puma -p 3006
      - 3006:3006
      - db
    stdin_open: true
    tty: true

      context: './service-4-web'
      dockerfile: $PWD/Dockerfile-React
      - $PWD/service-4-web/:/app/
    working_dir: /app
    command: npm start
      - 3007:3007
      - NODE_ENV=development

    driver: local

*using this docker-compose.yml configuration, service restart is not required on code change.


FROM ruby:2.5.3-alpine

RUN apk add --update bash build-base postgresql-dev tzdata
RUN gem install rails -v '5.1.6'

ADD Gemfile Gemfile.lock /app/
RUN bundle install
COPY . /app/


FROM node:11.6.0-alpine

WORKDIR '/app'

# Install yarn and other dependencies via apk
RUN apk update && apk add yarn python g++ make && rm -rf /var/cache/apk/*

COPY package.json yarn.lock /app/

RUN yarn install
RUN yarn global add react-scripts

COPY . ./

CMD ["npm", "run", "start"]

For adding new gems in rails api service, add gem in Gemfile and build new image for that service, example:

docker-compose build service-1-api

For adding new package in react app service, use

docker-compose run service-1-web yarn add `package-name`


Service Based Architecture is good alternative for applications where Manpower & Time are constraints.

In Next Blog I will write about deploying this Application on Amazon ECS(Elastic Container Service).

Posted in General | 1 Comment

Conversations that matter: Driving digital disruption in Banking

Banking and Chatbots

The word on the street says that banking and finance are moving towards digital transformation more aggressively than ever. Disruptive technologies like artificial intelligence and machine learning are key focus areas for FinTech leaders today. Developing long term solutions at scale to simplify finance operations is what will get developers the most brownie points!

Gartner predicts that companies offering personalization will outperform brands who don’t. With IoT in place now, the number of connected devices in the market has only increased, and the world already has 2.5 billion smartphone users. More than 37% of the world is using messaging apps today, and approximately 20 million already use smart speakers. The paradigm shift from non-personalized marketing to social media is representative of new age interactive customer experiences, and that’s the big fish to catch. Conversational commerce is a key driver of this transformation, and its recent popularity is well deserved. This also includes text based chatbots that increase consumer engagement especially in service-based sectors. In the last year, especially, this has grown incredibly and enabled businesses to connect to 5 times more the number of customers than usual. Impact? Their revenue grew by 10-20%. That is massive! Imagine the kind of growth opportunities out there!

Conversational Banking: Embracing digital transformation
The key differentiator for conversational commerce is that it allows users to converse through a platform of their choice, along with greater transparency. It is cost effective for banks and financial institutions, as a chatbot is simply a conversational algorithm embedded within a chat interface, i.e. a one-time investment. Intelligent chatbots generate a human like conversation with consumers, provide businesses with a dynamic understanding of their needs and while at it, optimize user data in real time. The smarter your bot becomes, the more data it collects. Initially, FinTech chatbots focused on customer experience but more recently, investments in contextual insights driven communication have made bots the new age contact executives, says PWC. Bots have also overtaken IVR and are helping users authenticate transactions seamlessly. In fact, chatbots can also provide CXOs with operational information and thus help them focus more on strategic business objectives, rather than remain caught up in day to day activities.

Adopting holistic, AI empowered support systems for back office

While optimizing customer experiences is priority, chatbots can be used to solve operational back office problems too. Backed by advanced machine learning and natural language processing (NLP), chatbots are essentially conversational analytics platforms that initiate actions without human intervention. A well designed chatbot reduces turn around time, provides instant information, enhances cross selling, improvises mundane queries and has the ability to provide omni channel experiences. For example, if a customer wants their bank statements, all they need to do is send a message to the chatbot. The details will be furnished to them within seconds! Based on the customer’s history and digital profile, chatbots also recommend investment options, provide market related news and suggest ways to utilize credit card points. Proactive suggestions for the win! That’s not all. Advanced chatbots can even analyze complex legal contracts much faster than lawyers, saving a large chunk of manpower and resources in the process. Granting access to software systems, resetting passwords and handling day to day IT operations is also achievable. Cognitive intelligence can further be utilized to pay down debt. Personal banking assistants are already anticipating questions for thousands of common FAQs, reducing the need for time consuming telephonic conversations.

Roadmap for the future: Intelligent conversations
An insights-driven bank complete with sales and marketing functions, and custom offerings based on global trends is the future of FinTech. Imagine an institution empowered with technology that can engage with consumers in real time, bridge gaps between existing legacy infrastructure through predictive data analytics and keep track of everything, all in one place. It will benefit not only the end consumer, but the bank’s employees as well by cutting down hours of repetitive work. For example, if a bank runs a loyalty program and wants to find out customers with the most number of transactions, they don’t need to manually look through their records. An AI and RPA powered chatbot can easily look through the customer data and respond via text! Scalable, high performance open source solutions implemented through apps add to dynamic UX as well. Mobile payments, digital wallets and UPI have also seen a massive escalation in the recent years, and non banking transactions like bill payments are adding to the boost. Soon, front office banking systems will be overtaken by mobile apps, and ticketing and back office systems will run on data analytics and blockchain. While certain processes like KYCs and internal employee management will definitely rely on the human touch, disruptive tech is here to stay. Conversational commerce may be in its infancy stage right now, but it holds the power to build strong business-consumer relationships.. The next era of FinTech will transform banks of today into cognitive financial institutions of tomorrow, and I, for one, can’t wait to see that happen!

Posted in Artificial Intelligence, Insuretech | Leave a comment

Android SMS Retriever​ API: To Auto Verify SMS

Content posted here with the permission of the author Chandrashekhar Sahu, who is currently employed at Josh Software. Original post available here.

The Android app needs SMS receive/read permission to retrieve SMS content.

Imagine an application where the use case is to get the SMS only for validating the user using OTP. And rest of the app does not use SMS reading feature again. Then in this case, it is a waste of the resources & time and of course code to check the SMS permissions.

To solve this problem, Google has introduced SMS Retriever API, this API allows to retrieve the OTP without needing of the SMS permission in your application.

Image Credit: Google

Dependency for SMS Retriever API

implementation ''
implementation ''
implementation ''
implementation ''

Obtain the user’s phone number (Phone Selector API)

First, we need the number of the user on which the OTP will be received. We create a hint request object and set the phone number identifier supported field to true.

HintRequest hintRequest = new HintRequest.Builder()

Then, we get a pending intent from that hint request for the phone number selector dialogue.

GoogleApiClient apiClient = new GoogleApiClient.Builder(getContext()).addApi(Auth.CREDENTIALS_API).enableAutoManage(getActivity(),
        GoogleApiHelper.getSafeAutoManageId(), new GoogleApiClient.OnConnectionFailedListener() {
            public void onConnectionFailed(@NonNull ConnectionResult connectionResult) {
                Log.e(TAG, "Client connection failed: " + connectionResult.getErrorMessage());

            PendingIntent intent = Auth.CredentialsApi.getHintPickerIntent(apiClent, hintRequest);
            startIntentSenderForResult(intent.getIntentSender(),RESOLVE_HINT, null,0,0,0);

Once the user selects the phone number, that phone number is returned to our app in the onActivityResult().

public void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
    if (requestCode == RC_PHONE_HINT) {
       if (data != null) {
          Credential cred = data.getParcelableExtra(Credential.EXTRA_KEY);
            if (cred != null) {
               final String unformattedPhone = cred.getId();

Start the SMS retriever

When we are ready to verify the user’s phone number, get an instance of the SmsRetrieverClientobject. Will call startSmsRetriever and attach success and failure listeners to the SMS retrieval task:

SmsRetrieverClient client = SmsRetriever.getClient(mContext);

// Starts SmsRetriever, waits for ONE matching SMS message until timeout
// (5 minutes).
Task<Void> task = client.startSmsRetriever();

// Listen for success/failure of the start Task. 
task.addOnSuccessListener(new OnSuccessListener<Void>() {
    public void onSuccess(Void aVoid) {
        // Log.d(TAG,"Successfully started retriever");

task.addOnFailureListener(new OnFailureListener() {
    public void onFailure(@NonNull Exception e) {
        Log.e(TAG, "Failed to start retriever");

Our server can then send the message to the phone using existing SMS infrastructure or service. When this message is received, Google Play services broadcasts an intent which contains the text of the message.

public class MySMSBroadcastReceiver extends BroadcastReceiver {
    public void onReceive(Context context, Intent intent) {
        if (SmsRetriever.SMS_RETRIEVED_ACTION.equals(intent.getAction())) {
            Bundle extras = intent.getExtras();
            Status status = (Status) extras.get(SmsRetriever.EXTRA_STATUS);
            switch (status.getStatusCode()) {
                case CommonStatusCodes.SUCCESS:
                    // Get SMS message contents
                    String message = (String) extras.get(SmsRetriever.EXTRA_SMS_MESSAGE);
                    // Extract one-time code from the message and complete verification
                    // by sending the code back to your server for SMS authenticity.
                case CommonStatusCodes.TIMEOUT:
                    // Waiting for SMS timed out (5 minutes)
                    // Handle the error ...

We need to register this BroadcastReceiver in our Manifest file as follows

        <action android:name="" />

Construct a verification message:

When our server receives a request to verify a phone number, first construct the verification message that you will send to the user’s device. This message must:

Otherwise, the contents of the verification message can be whatever you choose. It is helpful to create a message from which you can easily extract the one-time code later on. For example, a valid verification message might look like the following:

<#> Use 123456 as your verification code 

Optional: Save the phone number with Smart Lock for Passwords

Optionally, after the user has verified their phone number, We can prompt the user to save this phone number account with Smart Lock for Passwords so it will be available automatically in other apps and on other devices without having to type or select the phone number again.

Click here to get the source code.

Happy Coding 🙂

Posted in General | Leave a comment