Author: Ashok

Spring boot + AWS AppConfig 1. Setup AWS AppConfig Why AppConfig? AppConfig is a configuration management system provided by AWS which supports controlled rollouts to applications. If your application is already deployed in the AWS cloud environment and your application needs a dynamic configuration, then AppConfig might fit your need. In this tutorial, I’m using… Continue reading How to refresh application properties without restart

Merge sort is based on divide & conquer strategy. It continously divide the array into two halves until we reach one element where we cannot divide futher. Once divided, start merging them continously into a sorted array until we get the full array list. Divide & Conquer Recursive algorithm

Let’s assume that you have an AWS API Gateway proxy setup backed by lambda and lambda will handle all the requests. I had the same setup and like to test it in local using rest clients like Postman or Insomnia before deploying in the lambda. Prerequisites: In this tutorial, I have used AWS SAM CLI… Continue reading How to test AWS APIGateway – Lambda trigger in local

Recently I came across a book named Shape Up by Ryan Singer (https://twitter.com/rjs) about product development teams and strategies. The more I’ve started reading it, realized that most of the painful problems are real. Solutions mentioned in the book can be followed at the larger scale. In this article I’m not gonna review the book… Continue reading 6 week cycles instead of frequent meetings

The problem : Let’s assume that your application listen to two kafka topics and due to a bug or due to business needs you need to stop one of the consumer. If you’re using spring kafka, you can set “autoStartup“ property as false and restart the application. In this article, we are going to see… Continue reading Disable kafka listener programatically

A security group acts as a virtual firewall for your instance to control inbound and outbound traffic. When you launch an instance in a VPC, you can assign up to five security groups to the instance. And Security Groups can be attached to multiple instances. Security groups can only be created for a region/VPC. If… Continue reading AWS – Security Groups

Before start reading about the advanced IAM concepts, please go through this page Web Identity Federation Users access AWS resources after successful authentication with a web-based identity provider like Facebook, google. if the authentication is successful, users will get an authentication code from the web ID provider. Users can get temporary AWS security credentials &… Continue reading AWS Advanced IAM

Introduction : Let’s assume that in your application(not reactive), there is an API which depends on the response from event listeners. In real time, we use lot of event listeners in event driven architectures. It can be Another thread completion Kafka consumer completion Redis key state change, etc., Problem : Let’s say we create an… Continue reading Make request thread to wait and notify

Prerequisite: Algorithm, Sorting, Asymptotic complexity(time complexity, space complexity) Introduction: Bubble sort may look same as insertion sort, because the outcome of the bubble sort looks same as insertion sort. In case of sorting in ascending order, Insertion sort will keep taking out the min value at end of the each iteration, whereas bubble sort will take out… Continue reading Bubble Sort

Introduction Pivot, Divide and Conquer, Wall and Randomized Algorithms are the four terminologies we should know when come to quick sort. Pivot value selection Randomly select an element from the array. Here, we are choosing the last element as a pivot. Wall The left side of the wall will always have values that are smaller… Continue reading Quick sort