Piotr Nowicki's Blog

Why should you keep your AI agent in a separate environment?

Why should you keep your AI agent as a separate OS user?

How to find out what takes disk on your device if ‘du’ and ‘df’ shows different values.

How to find your device in a network if you don’t know what IP it has been assigned?

How to deal with container naming issue during update of container version

How to create a systemd service that will be automatically restart whenever some configuration file changes?

Let’s make it all work: private AWS ECR repository + custom external domain + ECR Credentials Helper Login + control permissions to fetch your images via Cognito

How to be able to use your custom domain when accessing docker repository hosted in private AWS ECR.

My name is Piotr Nowicki and this page is my blog mainly about Java related technologies.

How to replace GRUB with rEFInd as a boot manager on your Linux machine.

How to customize the Linux loading splashscreen using Plymouth and its themes.

How to configure LUKS (full disk encryption) to work with your YubiKey (FIDO2) so you can unlock your disk without typing password.

You have a Quarkus-based AWS Lambda using logback and want to send logs to logz.io?

You have your Lambda on AWS.

How to configure a new user password in AWS Cognito using plain HTTP calls?

How to easily revert to previously deployed docker image in case new version of your app behaves abnormally?

How to authenticate in AWS Cognito using plain HTTP calls?

Notes to my future-self about how to configure React.js frontend guarded by AWS Cognito to securely communicate with backend based on Serverless Framework (AWS Lambda behind Api Gateway).

Issues I bumped into during restoration of a PostgreSQL backup.

Root cause of a weird ’linux/arm/v7 not supported error'.

Imagine your code waits for some external system to respond.

AWS Systems Manager (formerly SSM) allows you to define secure, encrypted variables that you can read from other processes.

With Serverless Framework application it’s not enough to add proper gitignore statements.

If you’re planning to use Python moto library (to mock AWS resources) for unit tests and at the same time use integration tests - watch out as it can bite you!

Is it possible to create local environment for Serverless application?

How to effectively use stage promotions for your Serverless application.

Example how to name per-stage DynamoDB tables

Short introduction to AWS CodeBuild runtime images

If you have OpenWrt installed on your home router and you’d like to have a backup internet connection or a secondary WAN connection (e.g. to do a load-balancing between multiple WANs) then you might be interested in this post.

Years ago I was learning to pass Oracle Certified Expert, Java EE 6: JSP and Servlet Developer Exam (formerly Sun Certified Java Web Component Developer.)

You can enable CORS in API Gateway through AWS Console with few simple clicks: However there are some restrictions regarding when you can invoke this.

This is like a reminder to myself but assumed others might also be interested in it.

If you’d like to use CORS in your AWS API Gateway, it’s pretty easy to configure in the Console.

The biggest struggle I had in my mind when thinking about serverless and AWS itself was - how the hell to properly test it and create development environment?

I’m in the process of getting familiar with AWS and Serverless architecture and thought I’ll share some basics with you.

Want to use Payara / Glassfish with JAX-RS and Jackson to serialize/deserialize objects to/from JSON?

Some time ago I started to play with AngularJS to create a simple side-project app.

JBoss Keycloak is available as a Docker image.

Obeying to the TDD (Test Driven Development) saved me a lot of time so I decided to write about it.

When you have some non-trivial boolean statement used in if like: private void evict(Data data) { // ...

I’ve finished the migration process of my blog.

When you’re switching from one IDE to another, even if the codebase is the same, some differences might occur.

Few months ago Dane from JArchitect team was kind enough to provide me with a license for JArchitect 3.1.0 Professional Edition, a multiplatform (GNU/Linux, Mac, Windows) software for static code analysis.

Few days ago, during our regular code review, one of my colleagues raised a question what would happen – and if it’s even possible – when a CDI Observer (so a method with parameter annotated @Observes) would be invoked multiple times at the same time for…

Java EE 7 has been recently accepted by the Executive Committee.

Despite the fact that EJB inheritance sometimes uses Java inheritance – they’re not always the same.

This post will talk about possible ways of defining EJB views using annotations (I’ll just mention about using EJB Deployment Descriptor at the end.)

Let’s start with a short quiz.

Being in EJB and JPA world using CMT (Container Managed Transactions) is very comfortable.

UPDATE (5.08.2013) – I’ve updated this post to support JBoss EAP 6.1 Final (JBoss AS 7.2).