Elasticsearch with Spring Boot

Elasticsearch is a full-text search engine especially designed for working with large data sets. Following this description it is a natural choice to use it for storing and searching application logs. Together with Logstash and Kibana it is a part of powerful solution called Elastic Stack, that has already been described in some of my previous articles.
Keeping application logs is not the only one use case for Elasticsearch. It is often used as a secondary database for the application, that has primary relational database. Such an approach can be especially useful if you have to perform full-text search over large data set or just store many historical records that are no longer modified by the application. Of course there is always question about advantages and disadvantages of that approach.
When you are working with two different data sources that contain the same data, you have to first think about synchronization. You have several options. Depending on the relational database vendor, you can leverage binary or transaction logs, which contain the history of SQL updates. This approach requires some middleware that reads logs and then puts data to Elasticsearch. You can always move the whole responsibility to the database side (trigger) or into Elasticsearch side (JDBC plugins). Continue reading “Elasticsearch with Spring Boot”

Redis in Microservices Architecture

Redis can be widely used in microservices architecture. It is probably one of the few popular software solutions that may be leveraged by your application in such many different ways. Depending on the requirements it can acts as a primary database, cache, message broker. While it is also a key/value store we can use it as a configuration server or discovery server in your microservices architecture. Although it is usually defined as an in-memory data structure, we can also run it in persistent mode.
Today, I’m going to show you some examples of using Redis with microservices built on top of Spring Boot and Spring Cloud frameworks. These application will communicate between each other asynchronously using Redis Pub/Sub, using Redis as a cache or primary database, and finally used Redis as a configuration server. Continue reading “Redis in Microservices Architecture”

A Magic Around Spring Boot Externalized Configuration

There are some things I really like in Spring Boot, and one of them is an externalized (external) configuration. Spring Boot allows you to configure your application in many ways. You have 17 levels of loading configuration properties into application. All of them are described in the 24th Chapter of Spring Boot documentation available here.

This article was inspired by some last talks with developers about problems with the configuration of their applications. They haven’t heard about some interesting features that may be used to make it more flexible and clear. Continue reading “A Magic Around Spring Boot Externalized Configuration”

Introduction to Spring Data Redis

Redis is an in-memory data structure store with optional durability, used as database, cache and message broker. Currently, it is the most most popular tool in the key/value stores category: https://db-engines.com/en/ranking/key-value+store. The easiest way to integrate your application with Redis is through Spring Data Redis. You can use Spring RedisTemplate directly for that or you might as well use Spring Data Redis repositories. There are some limitations when you integrate with Redis via Spring Data Redis repositories. They require at least Redis Server version 2.8.0 and do not work with transactions. Therefore you need to disable transaction support for RedisTemplate, which is leveraged by Redis repositories. Continue reading “Introduction to Spring Data Redis”