Johan Zietsman's blog about software developmenthttps://johanzietsman.com/https://johanzietsman.com/actuator-and-prometheus/https://johanzietsman.com/actuator-and-prometheus/How to monitor and measure a Spring Boot Application's performance.Sat, 27 Feb 2016 00:00:00 GMThttps://johanzietsman.com/analyzing-the-merge-sort-algorithm/https://johanzietsman.com/analyzing-the-merge-sort-algorithm/An example of how to analyze the running time of a divide and conquer algorithm like merge sort.Sun, 22 May 2016 00:00:00 GMThttps://johanzietsman.com/basic-bump-api-using-rails/https://johanzietsman.com/basic-bump-api-using-rails/A protocol to link mobile devices through device bumping, a technique that requires accurate device geolocation.Sat, 02 Jan 2016 00:00:00 GMThttps://johanzietsman.com/boot-your-restful-api-using-spring/https://johanzietsman.com/boot-your-restful-api-using-spring/How to build a HATEOAS RESTful API using Spring Boot and Mongo.Wed, 17 Feb 2016 00:00:00 GMThttps://johanzietsman.com/building-tic-tac-toe-in-kotlin-with-functional-programming/https://johanzietsman.com/building-tic-tac-toe-in-kotlin-with-functional-programming/Explore the basics of functional programming in Kotlin as we dive into building a Tic Tac Toe game. Discover the power of pure functions, immutable state, and learn how to separate side effects from the functional core using an IO monad.Mon, 12 Jun 2023 00:00:00 GMThttps://johanzietsman.com/centralized-logging-with-cloudwatch-beanstalk-and-logback/https://johanzietsman.com/centralized-logging-with-cloudwatch-beanstalk-and-logback/How to collect performance metrics, access events and general logs in a centralized place when deploying to Elastic Beanstalk.Sat, 03 Sep 2016 00:00:00 GMThttps://johanzietsman.com/continuous-integration-delivery-and-deployment/https://johanzietsman.com/continuous-integration-delivery-and-deployment/An overview of continuous integration, delivery and deployment principles including deployment pipelines, feature flags, database migrations and testing strategy.Fri, 13 Jul 2018 00:00:00 GMThttps://johanzietsman.com/dockerize-a-spring-boot-application/https://johanzietsman.com/dockerize-a-spring-boot-application/A brief exploration of Docker and how it can be used to setup a complex application with several components.Sun, 13 Mar 2016 00:00:00 GMThttps://johanzietsman.com/event-driven-architecture-with-atom-feeds/https://johanzietsman.com/event-driven-architecture-with-atom-feeds/How to build an event-driven architecture, including event sourcing, without the need for messaging infrastructure using Atom feeds.Tue, 13 Apr 2021 00:00:00 GMThttps://johanzietsman.com/how-to-build-a-chat-app-using-webflux-websockets-react/https://johanzietsman.com/how-to-build-a-chat-app-using-webflux-websockets-react/Sun, 17 Sep 2017 00:00:00 GMThttps://johanzietsman.com/how-to-gather-performance-metrics-in-spring-batch/https://johanzietsman.com/how-to-gather-performance-metrics-in-spring-batch/This post will look at two ways to extract performance metrics out of a Spring Batch Job using Dropwizard Metrics.Mon, 09 Jul 2018 00:00:00 GMThttps://johanzietsman.com/how-to-reverse-indent-files-with-rxjs/https://johanzietsman.com/how-to-reverse-indent-files-with-rxjs/A Basic introduction to reactive programming using RxJS 5.0 by building a node script that reverse indents files.Tue, 05 Jun 2018 00:00:00 GMThttps://johanzietsman.com/how-to-setup-a-sonar-time-machine-for-an-angular-project/https://johanzietsman.com/how-to-setup-a-sonar-time-machine-for-an-angular-project/How to extract historical static analysis data from an Angular App into a new SonarQube server.Mon, 24 Aug 2020 00:00:00 GMThttps://johanzietsman.com/how-to-setup-jenkins-on-aws-with-spotfleet-slaves/https://johanzietsman.com/how-to-setup-jenkins-on-aws-with-spotfleet-slaves/Build CI/CD infrastructure with Ansible and CloudformationFri, 24 Apr 2020 00:00:00 GMThttps://johanzietsman.com/how-to-setup-kodi-on-a-raspberry-pi/https://johanzietsman.com/how-to-setup-kodi-on-a-raspberry-pi/Building a pocket sized media center (HTPC) using Arch Linux, Kodi and a Raspberry Pi 3.Mon, 14 Nov 2016 00:00:00 GMThttps://johanzietsman.com/how-to-use-jwt-and-oauth-with-spring-boot/https://johanzietsman.com/how-to-use-jwt-and-oauth-with-spring-boot/Do you need to setup Single Sign-on (SSO) for a microservice architecture? Thu, 01 Dec 2016 00:00:00 GMThttps://johanzietsman.com/kodi-add-on-development/https://johanzietsman.com/kodi-add-on-development/Lessons learned from developing my first Kodi add-on.Mon, 28 Nov 2016 00:00:00 GMThttps://johanzietsman.com/learning-react/https://johanzietsman.com/learning-react/Notes from learning React, Redux and the surrounding JavaScript ecosystem including ES6, middleware, routing and authentication.Thu, 17 Nov 2016 00:00:00 GMThttps://johanzietsman.com/machine-learning-random-forests/https://johanzietsman.com/machine-learning-random-forests/Notes on the random forest machine learning algorithm taken from the FastAI course.Fri, 24 Apr 2020 00:00:00 GMThttps://johanzietsman.com/masking-pii-in-logs/https://johanzietsman.com/masking-pii-in-logs/How to mask Personally Identifiable Information in logs using slf4j and AspectjMon, 01 Jun 2020 00:00:00 GMThttps://johanzietsman.com/microservices-platform-with-aws-fargate-rds/https://johanzietsman.com/microservices-platform-with-aws-fargate-rds/How to deploy Microservices on AWS Fargate backed by an Aurora Postgres RDS Cluster for persistence using Cloudformation and AnsibleSun, 28 Jun 2020 00:00:00 GMThttps://johanzietsman.com/microservices-with-spring-boot-and-spring-cloud/https://johanzietsman.com/microservices-with-spring-boot-and-spring-cloud/An overview of building microservices with Spring Boot covering RESTful API design, Swagger, Actuator and Spring Cloud components like Eureka, Feign, Zuul and Zipkin.Tue, 09 Jan 2018 00:00:00 GMThttps://johanzietsman.com/practical-machine-learning-with-fastai/https://johanzietsman.com/practical-machine-learning-with-fastai/Notes from the fast.ai course covering random forests, neural networks, deep learning and convolutional neural networks.Sun, 19 Aug 2018 00:00:00 GMThttps://johanzietsman.com/ralph-loop/https://johanzietsman.com/ralph-loop/Using a simple bash loop to orchestrate an AI agent across multiple sessions — from specification to working code.Mon, 06 Apr 2026 00:00:00 GMThttps://johanzietsman.com/rxjs/https://johanzietsman.com/rxjs/An exploration of reactive programming with RxJS covering observables, operators, subjects, hot vs cold observables and error handling.Mon, 06 Mar 2017 00:00:00 GMThttps://johanzietsman.com/sequential-ajax-and-jquerys-promise/https://johanzietsman.com/sequential-ajax-and-jquerys-promise/Wed, 20 Jan 2016 00:00:00 GMThttps://johanzietsman.com/specs-are-grown-not-written/https://johanzietsman.com/specs-are-grown-not-written/A self-assessment of the 7 skills every AI-augmented developer needs, from specification precision to token economics.Fri, 27 Mar 2026 00:00:00 GMThttps://johanzietsman.com/ssl-on-apache-with-self-signed-certificates/https://johanzietsman.com/ssl-on-apache-with-self-signed-certificates/How to setup SSL for multiple Virtual Hosts in Apache using self signed certificates.Thu, 07 Jul 2016 00:00:00 GMThttps://johanzietsman.com/tech-interview-cheatsheet-graphs/https://johanzietsman.com/tech-interview-cheatsheet-graphs/Overview of Graphs, including graph representations, depth first search (DFS), breadth first search (BFS) and Eulerian paths.Wed, 13 May 2020 00:00:00 GMThttps://johanzietsman.com/tech-interview-cheatsheet-lists-search-sort/https://johanzietsman.com/tech-interview-cheatsheet-lists-search-sort/An overview of Binary Search algorithms, including Bubble, Merge and Quick Sort.Tue, 16 May 2017 00:00:00 GMThttps://johanzietsman.com/tech-interview-cheatsheet-maps-hashing/https://johanzietsman.com/tech-interview-cheatsheet-maps-hashing/Sat, 27 May 2017 00:00:00 GMThttps://johanzietsman.com/tech-interview-cheatsheet-trees/https://johanzietsman.com/tech-interview-cheatsheet-trees/Overview of Trees, including depth first search (DFS), breadth first search (BFS), Binary Search Trees & Self Balancing Trees.Sat, 27 May 2017 00:00:00 GMThttps://johanzietsman.com/visualizing-a-spring-context-graph/https://johanzietsman.com/visualizing-a-spring-context-graph/How to examine the runtime state of a Spring context with the help of an object graph.Tue, 29 Mar 2016 00:00:00 GMT