Dual Writes often happens in a microservices based architecture. Whenever a piece of data changes in one place, we need to persist or react on it on multiple places. Imagine a user bought a product on our website and we need to save order in the database and inform a delivery service that they should […]
This article describes how a Cloud Native application should look like, it is based on the well known 12 Factors. At the moment of writing this article, in my understanding, the Cloud Native is not only about code that developers write, but it is also a way of organizing engineering teams so that their work […]
The Unit return type declaration is optional for functions. The following codes are equivalent. Single-Expression functions:When a function returns a single expression, the curly braces can be omitted and the body is specified after = symbol fun sum(a : Int, b : Int) : Int = a + b Explicitly declaring the return type is […]
Hello World Kotlin programs start at the main function. Here is an example of a simple Kotlin “Hello World” program: When compiled this code will be compiled into a file named after file name + ‘Kt’, if your file was named Main.kt, the compiled code will be in a file name MainKt. In the above […]
When writing software, it is important to keep you organized and focused, losing focus or vague understanding requirements will endup in a bad written system in the best case. If you have got a large body of work that needs to go into production there are lots potential things that can go wrong. When you […]
In this article I would like to explain what kind of problems can we encounter when working with Apache Kafka and how we can address them. Apache Kafka is a distributed streaming platform, it is used for building real-time data pipelines, because of persistence of topics it can be used for processing historical message events; […]
The purpose of this article is to explain (mainly to myself) a technique for creating good indexes for mysql database. Before starting I would like to discuss about selectivity. Index selectivity is the ratio of number of distinct indexed values ( the cardinality) over the total numbers of rows in the table (#T), and ranges […]
Over the last decade or so, Refactoring has become a widely used technique to keep a high internal quality for a codebase. However most teams don’t make enough use of refactoring because they aren’t aware of the various workflows in which you can use it. In this keynote talk from OOP 2014 in Munich, Martin […]
Consuming messages is similar with producing messages because of abstraction offered by kafka library. There are two methods for consuming messages, subscribe(List<String>) can be used to consume messages from one or more topics, assign(List<TopicPartition>) should be used when we are interested to consume messages from specific partitions.
