All posts by
Filip Marszelewski

Jul 15 2019

Migrating a microservice to Spring WebFlux

Reactive programming has been a hot topic on many conference talks for at least several months. It’s effortless to find simple code examples and tutorials and to apply them to greenfield projects. Things become a little bit more complicated when production services with millions of users and thousands of requests per second need to be migrated from existing solutions. In this article, I would like to discuss migration strategy from Spring Web MVC to Spring WebFlux by the example of one of the Allegro microservices. I’m going to show some common pitfalls as well as how performance metrics in production were affected by migration.

Jan 26 2017

Estimating the cache efficiency using big data

Caching is a good and well-known technique used to increase application performance and decrease overall system load. Usually small or medium data sets, which are often read and rarely changed, are considered as a good candidate for caching. In this article we focus on determining optimal cache size based on big data techniques.

Jul 9 2015

Testing server faults with Wiremock

SOA (Service Oriented Architecture) as a modern approach to build distributed enterprise applications gives us many benefits, including resiliency and fault-tolerance. On the other hand, there are many new kinds of SOA-specific faults, like publishing, discovery, composition, binding or execution faults (as stated in A Fault Taxonomy for Service-Oriented Architecture). Error handling is one of the most important things to have services right designed and implemented (see article Error Handling Considerations in SOA Analysis & Design). In this article, I want to focus only on a small aspect of this broad subject: unexpected service behaviors which, if not properly handled by the client, can lead to application inaccessibility.

Jan 16 2015

We were at QCon SF 2014

QCon is one of the most identifiable conferences in IT world. Several times every year it connects IT professionals from the whole world in such a well-known locations like San Francisco, New York, Shanghai, Tokyo, Beijing or London. The main idea of conference is to facilitate the spread of knowledge and innovation in developer community.

Filip Marszelewski

Software engineer and team leader at the team responsible for Allegro listing. Especially interested in chaos engineering and building resilient systems in microservices architecture using reactive and asynchronous patterns.