# Paweł Chudzik Recent content on tech\_gibberish This is one page of public article previews, not the complete archive. Follow Next page to continue. Summaries are not the original full articles. ## How to setup remote docker host DevFeed: [How to setup remote docker host]() Original publisher: [Read original article]() Published: 2022-09-26T00:00:00Z Content type: tutorial Language: en Sources: [Paweł Chudzik]() Topics: [Docker](), [Image](), [docker images](), [Testcontainers](), [Amazon EC2](), [Amazon Web Services](), [Linux](), [TLS (Transport Layer Security)](), [x86]() Tags: [arm](), [aws](), [containers](), [docker](), [docker-images](), [ec2](), [how-to](), [integration-test](), [linux](), [remote](), [tls](), [x86]() ### AI overview This tutorial explains how to set up a remote Docker host for integration tests when required ARM images are unavailable. It uses a Linux x86_64 AWS EC2 machine, configures TLS access to the Docker daemon, and connects a local Docker client to the remote host. ### Source excerpt Not all docker images are available for ARM architecture (hopefully this will improve over time). Right now I'm working on a project where images for ARM are not available. Emulation works ok (but slow) most of the time. Lately, I stumbled upon an interesting performance/startup issue when running amd64-based containers using testcontainers in an integration test. Read more ## Multiple GIT identities DevFeed: [Multiple GIT identities]() Original publisher: [Read original article]() Published: 2022-05-12T00:00:00Z Content type: tutorial Language: en Sources: [Paweł Chudzik]() Topics: [Git](), [GitLab](), [ssh](), [configuration]() Tags: [configuration](), [email](), [gerrit](), [git](), [github](), [gitlab](), [go](), [ssh]() ### AI overview A tutorial on configuring multiple Git identities for separate work and personal GitLab accounts. It explains using separate SSH keys and SSH host configuration to select the appropriate identity, with notes that the approach also works with GitHub and other Git services. ### Source excerpt I have two GitLab accounts - "work account" and "personal account". One is for my professional work, it is registered to my work email. The second account is for my private/learning projects registered with my private email address. I want to keep those things separate and use two different identities when working with git. Lately, I've bought a new computer and had to set up this again. Read more ## Gson failure in end-to-end tests DevFeed: [Gson failure in end-to-end tests]() Original publisher: [Read original article]() Published: 2022-01-23T00:00:00Z Content type: article Language: en Sources: [Paweł Chudzik]() Topics: [Gson](), [Java](), [JSON](), [Testing](), [Jackson]() Tags: [e2e](), [enum](), [gson](), [jackson](), [java](), [json](), [tests](), [work]() ### AI overview This article explains that Gson can silently ignore JSON deserialization problems, such as an unknown enum value, allowing end-to-end tests to pass even when an API contract is broken. It contrasts this behavior with Jackson and describes migrating tests from Gson to Jackson. ### Source excerpt Using Gson in your e2e tests might result in tests passing even when contract is broken. Gson is quite imprecise when it comes to deserializing objects from json. Is there any difference between an enum and a string? Is there any difference between s string and a number? Using Java you might answer: sure there is. Even when talking about JSON you'll answer: yeah there is a difference. But for GSON? Meh whatever. Read more ## Synchronous communication - circuit breaker and fallback DevFeed: [Synchronous communication - circuit breaker and fallback]() Original publisher: [Read original article]() Published: 2020-05-07T00:00:00Z Content type: tutorial Language: en Sources: [Paweł Chudzik]() Topics: [Development](), [Software Engineering](), [Network]() Tags: [behavior](), [communication](), [network](), [self-healing](), [services](), [software-development](), [systems]() ### AI overview This tutorial explains the circuit breaker and fallback communication patterns for preventing cascading failures and giving dependent services time to recover. It describes closed, open, and half-open states, then examines implementations from Hystrix and resilience4j using a controllable failing service. ### Source excerpt The circuit breaker is a communication pattern that helps to avoid cascading failure of the system and gives dependent services time to recover. Along with fallback values defined by the developer, it gives a pretty wide safe net when communication channel is broken. Read more ## Working with OpenAPI contract in multiple files DevFeed: [Working with OpenAPI contract in multiple files]() Original publisher: [Read original article]() Published: 2020-04-23T00:00:00Z Content type: tutorial Language: en Sources: [Paweł Chudzik]() Topics: [OpenAPI Specification](), [Swagger](), [API]() Tags: [api](), [code](), [download](), [editor](), [embedded](), [github-issues](), [openapi](), [openapi-specification](), [swagger]() ### AI overview This tutorial explains how to split a large OpenAPI specification into multiple files and work with external references. It discusses Swagger Editor's limitations, Stoplight Studio, swagger-ui-watcher, and a workflow for organizing a pet store API across separate files. ### Source excerpt Real-life OpenAPI specification files tend to go really big really fast. In this post, I'll try to explore how we can split single specification file into multiple files and don't get crazy while scrolling up and down like a mad man. Read more ## Collection like objects in python DevFeed: [Collection like objects in python]() Original publisher: [Read original article]() Published: 2020-04-15T00:00:00Z Content type: tutorial Language: en Sources: [Paweł Chudzik]() Topics: [Python](), [Programming](), [Protocol (disambiguation)](), [Code]() Tags: [behavior](), [class](), [collections](), [dsl](), [functional](), [list](), [programming-language](), [protocol](), [python](), [set](), [slices]() ### AI overview A tutorial on implementing Python collection-like objects using the collections protocol. It discusses slices and methods such as __getitem__, __setitem__, __delitem__, __iter__, __contains__, and __missing__, including how they support collection behavior and domain-specific language extensions. ### Source excerpt Collections are an important part of every programming language. In python, there is a couple of built-in collections like list, set, dictionary but I'm not going to dig into them now. In this post, I'll explore what it takes to implement collection like objects on your own using collections protocol. Read more ## Object oriented programming in Python DevFeed: [Object oriented programming in Python]() Original publisher: [Read original article]() Published: 2020-03-25T00:00:00Z Content type: tutorial Language: en Sources: [Paweł Chudzik]() Topics: [Python](), [Programming]() Tags: [object](), [programming](), [python]() ### AI overview A practical reference to object-oriented programming in Python, covering duck typing, object creation and initialization, finalization, and object representation methods such as __repr__, __str__, and __format__. ### Source excerpt Working with python is fun (as with any language you get hooked up on). You can write simple scripts with it, or complex programs and utilities. The most surprising thing for people coming from the java world might be that in this "scripting" language everything is an object. In this post, I'll explore basic protocols available for user-defined objects. Read more ## Synchronous communication - connection settings and retries DevFeed: [Synchronous communication - connection settings and retries]() Original publisher: [Read original article]() Published: 2020-03-17T00:00:00Z Content type: tutorial Language: en Sources: [Paweł Chudzik]() Topics: [HTTP](), [configuration]() Tags: [configuration](), [errors](), [http](), [network](), [request](), [retry](), [test]() ### AI overview This tutorial explains how to configure connection settings and retries for synchronous communication with Feign. It covers reviewing default connection and read timeouts, choosing retry counts based on service response times and SLAs, adding delays between attempts, and retrying selected errors such as HTTP 503 without contributing to cascading failures. ### Source excerpt The simplest possible strategy that can help with communication issues is retrying to execute the request again. Maybe it was just a network glitch and it will work just fine when you try to call it again. Introducing retries is a relatively simple step that can improve the stability of your service. But before adding retries check if you'll not be waiting for 2 minutes for establishing the connection... Read more ## Synchronous services communication DevFeed: [Synchronous services communication]() Original publisher: [Read original article]() Published: 2020-02-28T00:00:00Z Content type: tutorial Language: en Sources: [Paweł Chudzik]() Topics: [systems](), [Availability](), [Code]() Tags: [availability](), [programming](), [systems]() ### AI overview An examination of how synchronous communication between services affects overall reliability. It explains how dependencies such as databases and other internal or external services compound failure probabilities, and discusses common sources of failure. ### Source excerpt At work, we are splitting the monolithic application into smaller services. From time to time we have some challenges in doing it the right way. Lately, most of the splitting is focused on cutting out frontends to be outside of the monolith. It gives solid results as we are getting logic and business rules in one place. The downside is that most of the communication has to be synchronous which creates interesting problems to solve. Read more ## How I Built and Manage This Blog with Hugo, Markdown, Docker, and Automation DevFeed: [How I Built and Manage This Blog with Hugo, Markdown, Docker, and Automation]() Original publisher: [Read original article]() Published: 2020-02-14T00:00:00Z Content type: tutorial Language: en Sources: [Paweł Chudzik]() Topics: [Hugo](), [Markdown](), [Docker](), [Automation](), [Continuous Deployment (CD)]() Tags: [automation](), [continuous-deployment](), [docker](), [hugo](), [markdown]() ### AI overview The author describes how their blog evolved over three years, covering Hugo, Markdown and Asciidoc, theme customization, Docker-based local development, scripts, and continuous deployment possibilities. ### Source excerpt In this post, I'd like to show you how I've started with writing this blog. How the process evolved during 3 years of writing. How I've finally managed to set up everything in a way that works for me now. If you don't blog yet this might help you out with technical details on how you can start easily. If you already have a blog maybe you'll be able to pick up some ideas. Read more ## Log4j 2: A High-Level Overview of Logging Features DevFeed: [Log4j 2: A High-Level Overview of Logging Features]() Original publisher: [Read original article]() Published: 2020-01-20T00:00:00Z Content type: tutorial Language: en Sources: [Paweł Chudzik]() Topics: [log4j](), [Logging](), [Library](), [audit](), [context](), [tracing](), [configuration]() Tags: [audit](), [configuration](), [context](), [library](), [log4j](), [logging](), [tracing]() ### AI overview A high-level overview of Log4j 2 features, including structured Message objects, event logging for audits, ThreadContext correlation IDs, flow tracing, markers, and configurable appenders. ### Source excerpt When I've first learned that there is something more than printing things to console log4j was state of the art solution. Then SLF4J joined the party and improved where log4j was lacking. The new version of LOG4J is available for some time already and I didn't have a chance to look at what if offers. Let's examine what's possible with the second version of a very well known logging library. Read more ## Toggling Spring Cache at Runtime with a Custom Cache Manager DevFeed: [Toggling Spring Cache at Runtime with a Custom Cache Manager]() Original publisher: [Read original article]() Published: 2020-01-09T00:00:00Z Content type: tutorial Language: en Sources: [Paweł Chudzik]() Topics: [Cache](), [Caching](), [Redis](), [configuration](), [Code]() Tags: [cache](), [caching](), [code](), [configuration](), [metrics](), [redis]() ### AI overview This proof-of-concept article describes how to enable or disable Spring caching at runtime using a custom cache manager. The manager delegates to Redis when caching is enabled and bypasses it when disabled, allowing behavior to be tested against production-like traffic and metrics. ### Source excerpt Sometimes it's good to have an option to try something out on the live environment. Checking things against production like traffic is the most reliable way to gather real-life metrics. In this post, I'm going to try and set up spring cache with a toggle. It'll be possible to turn it off and on during application runtime possibly using external toggle service. Read more ## Practical Skills and Tools That Help Software Developers Work Effectively DevFeed: [Practical Skills and Tools That Help Software Developers Work Effectively]() Original publisher: [Read original article]() Published: 2019-12-27T00:00:00Z Content type: article Language: en Sources: [Paweł Chudzik]() Topics: [Command-line interface](), [Programming](), [Automation](), [Script](), [DevOps](), [Docker](), [Git](), [Gradle](), [kubectl](), [Kubernetes](), [Maven](), [ssh]() Tags: [automation](), [cli](), [command-line](), [data-analysis](), [devops](), [docker](), [git](), [gradle](), [kubectl](), [kubernetes](), [maven](), [programming](), [script](), [ssh]() ### AI overview This article discusses practical skills and tools that shape how software developers work, even when they are not emphasized in job interviews. It recommends command-line fluency, shell utilities, small automation scripts, spreadsheets for data analysis, pragmatic experimentation, and learning from DevOps and QA perspectives. ### Source excerpt On almost every job interview there are questions about frameworks, programming principles, maybe some coding or whiteboard architecting. On the other side, there is the way you work. Tools and skills you use on a daily basis which define how you work. No one really asks about those things but I find them quite important. Read more ## Microservices are hard DevFeed: [Microservices are hard]() Original publisher: [Read original article]() Published: 2019-12-12T00:00:00Z Content type: article Language: en Sources: [Paweł Chudzik]() Topics: [Microservices](), [migration](), [Architecture & Design](), [Persistence](), [Databases](), [HTTP](), [Cloud](), [Amazon Web Services](), [web applications]() Tags: [architecture](), [aws](), [cloud](), [database](), [http](), [implement](), [microservices](), [migration](), [persistence](), [services]() ### AI overview The article describes the difficulties of gradually migrating a monolithic application toward microservices and a service-oriented architecture. It presents an interim report-generation flow in which the monolith and a new service exchange data over HTTP while data remains split across their databases. ### Source excerpt At work, we are slowly breaking down the monolithic application into smaller manageable services. Some time ago we had a very interesting issue which proved that microservices are hard to implement. It's especially true if you are not there yet but somewhere in the middle. When you need to introduce intermediate solutions which will enable you to work further on the migration to service oriented architecture. Read more ## Use replica database for read-only transactions DevFeed: [Use replica database for read-only transactions]() Original publisher: [Read original article]() Published: 2019-11-27T00:00:00Z Content type: tutorial Language: en Sources: [Paweł Chudzik]() Topics: [Transactions](), [Spring Boot](), [MariaDB](), [Replication](), [Docker Compose](), [Amazon Web Services]() Tags: [aws](), [docker-compose](), [mariadb](), [replication](), [spring-boot](), [transactions]() ### AI overview This tutorial shows how to configure a Spring Boot application to route read-only transactions to a replica database while continuing to write data to the master. It describes a setup using MariaDB instances, replication, Docker Compose, and AWS RDS, while noting that the example replication configuration is intended for testing rather than production. ### Source excerpt Some time ago we had a problem with performance caused by generating big reports for users. During one of the firehouse meetings, there was an idea to generate reports from the replica database. We've solved the issue differently but the idea got me interested. In this post, I'll configure spring-boot based application to use the replica database for all read-only transactions. Read more ## Error handling with @Transactional DevFeed: [Error handling with @Transactional]() Original publisher: [Read original article]() Published: 2019-11-11T00:00:00Z Content type: tutorial Language: en Sources: [Paweł Chudzik]() Topics: [Spring Framework](), [Transactions](), [Exception](), [Error Handling]() Tags: [bug](), [error-handling](), [exception](), [spring](), [spring-framework](), [transactions]() ### AI overview This article explains Spring transaction rollback behavior for runtime and checked exceptions, including how explicit rollback configuration affects checked exceptions. It also discusses how Lombok's @SneakyThrows interacts with @Transactional. ### Source excerpt You probably already know that by default in spring transactions are rolled back only for runtime exceptions. When a checked exception is thrown from your code and you don't explicitly tell spring that it should rollback the transaction then it get's committed. In this post, I'm going to create simple reference material on when transactions are rollback when using Spring and Lombok. Read more ## asciidoc documentation DevFeed: [asciidoc documentation]() Original publisher: [Read original article]() Published: 2019-10-24T00:00:00Z Content type: tutorial Language: en Sources: [Paweł Chudzik]() Topics: [Documentation](), [Development](), [Code](), [Wiki]() Tags: [bitbucket](), [code](), [development](), [documentation](), [github](), [gitlab](), [html](), [markdown](), [pdf](), [repo]() ### AI overview This tutorial explores using Asciidoctor for technical documentation stored alongside source code. It explains how repository-based documentation can be kept current, updated by developers, and reviewed with code, while noting that larger documentation projects may benefit from features such as diagrams, source-code inclusion, and HTML or PDF export. ### Source excerpt One thing that a lot of people hate to do is writing documentation. Usually, it's postponed until development is finished and once it's done there is rarely time to do it properly. If you get past the struggle of writing it down there is always a problem of keeping it up to date. To avoid those pain points I'm going to explore what we can do with Asciidoctor to simplify this problem. Read more ## Awaitility DevFeed: [Awaitility]() Original publisher: [Read original article]() Published: 2019-10-10T00:00:00Z Content type: tutorial Language: en Sources: [Paweł Chudzik]() Topics: [Library](), [Testing](), [Concurrency](), [async](), [Code]() Tags: [asynchronous](), [concurrency](), [examples](), [executorservice](), [library](), [multithreading](), [queue](), [testing](), [threads]() ### AI overview This tutorial introduces Awaitility, a small library for testing asynchronous code. It explains how Awaitility can express expectations for multithreaded systems concisely, using a producer-consumer example with a queue. ### Source excerpt If you are not working with multithreading programming and don't have to test any asynchronous code then this post will probably do you nothing good. But if you have ever struggled with testing some logic running in multiple threads and you don't know Awaitility. A small library helps testing asynchronous code. If you've never heard of it then you should continue reading. Read more ## Answers in mockito DevFeed: [Answers in mockito]() Original publisher: [Read original article]() Published: 2019-09-22T00:00:00Z Content type: tutorial Language: en Sources: [Paweł Chudzik]() Topics: [Mocking](), [Library](), [test](), [legacy](), [Refactoring](), [Exception]() Tags: [developer](), [exception](), [legacy](), [mocking](), [mockito](), [refactoring](), [techniques](), [test]() ### AI overview This tutorial explains Mockito stubbing strategies and answers, including default returns, real method calls, null handling, self-returning builders, generated mocks, and deep stubs. It also discusses when these techniques may indicate legacy code or problematic design. ### Source excerpt Mocking library is an important tool in every developer toolbox. Sometimes you want to do things that at first glance look a bit more complex than returning number 42 from some method. Let's see what stubbing techniques are available in Mockito out of the box and what they offer. Read more ## Hands-on RedisTemplate DevFeed: [Hands-on RedisTemplate]() Original publisher: [Read original article]() Published: 2019-09-11T00:00:00Z Content type: tutorial Language: en Sources: [Paweł Chudzik]() Topics: [Redis](), [Caching](), [API](), [implementation]() Tags: [api](), [cache](), [caching](), [implementation](), [redis]() ### AI overview A hands-on tutorial explains how to add item-level caching with Spring's RedisTemplate when the existing cache abstraction cannot invalidate individual values within cached collections. It describes introducing a cache abstraction, writing tests, handling JSON serialization, and implementing the Redis-backed service. ### Source excerpt We are improving cache in the project Im working on. In the code base I've found a method which accepted a collection of ids and returned collection of objects for those ids. My goal was to add cache on individual values returned by the method. Creation of items was IO heavy and time-consuming operation so removal of cache was not an option. Read more ## ArchUnit DevFeed: [ArchUnit]() Original publisher: [Read original article]() Published: 2019-08-22T00:00:00Z Content type: tutorial Language: en Sources: [Paweł Chudzik]() Topics: [Library](), [Java](), [unit test]() Tags: [architecture](), [how-to](), [java](), [structure](), [test](), [tests](), [unit-test]() ### AI overview This tutorial introduces ArchUnit, a free Java library for testing architecture conventions with standard Java unit test frameworks. It demonstrates checks for test naming conventions, package and class dependencies, and preventing internal classes from appearing in public APIs. ### Source excerpt In the past, I've implemented couple of tests that aimed to verify naming conventions or some other practices team agreed upon. And presented a way how to ensure they are followed. When I've been writing those I was not aware that there is a library that aims to test architecture conventions - ArchUnit in this post I'll write a simple test case to check what's possible out of the box. Read more ## Using Advent of Code to Practice Python and Algorithm Implementation DevFeed: [Using Advent of Code to Practice Python and Algorithm Implementation]() Original publisher: [Read original article]() Published: 2019-08-13T00:00:00Z Content type: opinion Language: en Sources: [Paweł Chudzik]() Topics: [Python](), [Advent of Code](), [Programming](), [Algorithms](), [Graphs](), [Mazes]() Tags: [adventofcode](), [algorithm](), [algorithms](), [how-to](), [puzzles](), [python]() ### AI overview The author describes using Advent of Code puzzles to deepen Python knowledge and practice algorithm implementation. A maze-solving problem provided practice with graph traversal, shortest-path reasoning, and measuring traveled distance. ### Source excerpt I'm learning python for some time now. I've made myself familiar with the syntax and then started looking into other ways to increase my knowledge about language and learn its quirks. I've found a very nice site that allows me to practice basics and strengthen different kind of muscles that I'm using in my day job - adventofcode. Read more ## Testcontainers DevFeed: [Testcontainers]() Original publisher: [Read original article]() Published: 2019-07-18T00:00:00Z Content type: tutorial Language: en Sources: [Paweł Chudzik]() Topics: [Testcontainers](), [Testing](), [Docker](), [Redis]() Tags: [docker](), [integration](), [redis](), [services](), [testcontainers](), [testing]() ### AI overview A tutorial on using Testcontainers to run Docker containers for integration tests. It demonstrates testing communication with a live Redis instance without manually preparing infrastructure. ### Source excerpt Recently I've found a very interesting project which allows to spin up docker containers for test purposes. Writing tests checking integration with external services is not an easy task. With testcontainers library it gets simpler because you can have external service up and running just for your test in a couple of lines of code. Read more ## Spock extensions DevFeed: [Spock extensions]() Original publisher: [Read original article]() Published: 2019-07-11T00:00:00Z Content type: tutorial Language: en Sources: [Paweł Chudzik]() Topics: [Framework](), [implementation](), [Spring Boot]() Tags: [extensions](), [framework](), [how-to](), [implementation](), [spring-boot](), [tests]() ### AI overview A tutorial on creating a simple annotation-based Spock extension to execute additional logic before tests and change a toggle during test execution. It explains the extension annotation, implementation, interceptors, and lifecycle methods, with Spring Boot integration as context. ### Source excerpt Recently I had to set up some extra logic to be executed before running tests. I had two options - create yet another abstract class with some behavior or somehow extend Spock and introduce extra logic to be executed just before actual test starts. As we already have enough of abstract classes I decided to try and do the second option. Read more [Next page]()