Even though a lot of software development is high-level stuff which does not require the developer to delve into the details of how things work under the hood, in certain situations it can be very helpful to know what sort of low-level operations an application is performing. Two typical scenarios are performance tuning and debugging.
In this post I would like to show you how to add a resource programatically in Jersey container. We start from a business use case that needs to be implemented. What we are trying to achieve is to allow external clients to use some resources of internal microservices. I am aware of the fact that the solution we are going to discuss is not the best way to solve the problem. Choosing the best solution lies outside the scope of this post. What is covered in this post are the steps and solutions we tried to use in order to solve the problem.
When you publish your service API it is crucial to make it easy to upgrade. If you forget about it, you might end up in dependency hell. Each attempt to change your API will force you to contact all your clients and tell them to upgrade their software. As a result, both you and your clients will be very unhappy. You can mitigate it by providing multiple versions of your resources. But there is no single way how to manage them. Different companies solve it in different ways. Below you find three most popular approaches.
This is the second part of the article about how, in one of the teams at Allegro Group, we combined the Minimum Viable Product (MVP) and Walking Skeleton concepts with the Story Mapping technique to quickly define the scope of the forthcoming project and eventually built a reliable and valuable product in a limited amount of time.
Any programmer can admit that working with code that has been developed for years by many people is a difficult task. Keeping your own application architecture clean is troublesome, and it gets even more challenging in case of an application that was written by other programmers several years ago. One can enjoy writing new applications and tools that do not carry any burden, but each product evolves together with its business assumptions. Moreover, new features are added and the application needs to be constantly improved.
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.
At the beginning of December we published our first post about Swift. Today we want to continue the Swift thread and introduce a few interesting facts about functions in Swift language.
On 23rd and 24th October, the Allegro platform suffered a failure of a subsystem responsible for asynchronous distributed task processing. The subsystem consists of several daemon processes, Gearman job server, Redis and Oracle databases. The problem affected many areas, e.g. features such as purchasing numerous offers via cart and bulk offer editing (including price list editing) did not work at all. Moreover, it partially failed to send daily newsletter with new offers. Also some parts of internal administration panel were affected.
Devoxx (formerly JavaPolis) is an annual Java-centric conference organized by BeJUG that takes place in Antwerp, Belgium. Such a big Java event can‘t go unnoticed by Allegro. This year five representatives of our company had a chance to experience five full days of Devoxx.
This post is an introduction to the mysterious and alien world of aspect-oriented programming, or aspects for short. At first sight it is difficult to understand why to use aspects and how a project can benefit from this technology. The simplest use case where we can use an aspect is logging. I believe that everyone saw, or even wrote on their own, a piece of code where the business logic was interweaving with infrastructure code:
In distributed environments it is crucial to have a common, standardized language which services can use to exchange information between each other. At Allegro, to meet this goal, we’ve chosen the REST architecture.
Big Data Spain is an annual conference on Big Data and related topics held in the suburbs of Madrid. This year’s, i.e. third, edition has so far been the biggest; it has attracted more than 500 guests and various speakers including Big Data celebrities like Paco Nathan of Databricks. During two days of the conference, guests could attend many keynotes, speeches and workshops and learn about variuos products, services and specific use-cases, in both English and Spanish. Allegro was represented by two employees with a presentation on Hadoop pitfalls and gotchas.
Two weeks ago, I attended Swift Warsaw as a speaker, holding a presentation on “Swift Runtime — Swift Method Dispatching”. I promised to summarise the talk in an article, so hereby I keep my promise.
This post is about migrating a real-world, non-trivial, business-critical application from Java 7 to Java 8. When searching for a JDK 8 migration guide, you can often find blog posts that claim to be helpful but in reality only repeat the list of features found in release notes and offer no insight into issues you may encounter in practice. Having no migration guide during our own migration, we decided to create one. This is a report right from the trenches, no details spared, casualties included.
At Allegro, we always try to pick the right tool for the job. As a result, despite focusing on JVM for implementing our services, we do use Python extensively for infrastructure automation and management.
Introduction of Swift programming language during WWDC 2014 was big news in developers’ world. The community warmly welcomed the language created by Apple and many developers started learning and using it immediately. This article explains what Swift is and its basic concepts. If you are an iOS (or OS X) developer it means that you probably already know all the things described below, but if you haven’t started your iOS development adventure yet (but you want to), this article could be a good introduction for you.
Two weeks ago we attended AWS re:invent conference in Las Vegas. Our company was represented by Wojciech Lesicki (Product Owner of our cloud infrastructure), Sebastian Pietrowski (Head of Architecture and Operations) and Mateusz Gajewski (Solutions Architect). This post summarises new product announcements made during the keynotes, our impressions on breakout sessions, bootcamps and conference itself.
REST (Representational State Transfer) has become very popular over the course of the past few years. It has happened so not only because of growing popularity of lightweight Web frameworks (like Angular.js) but also due to the new Microservice Architecture hype (thank you Netlifx). Frameworks like Spring add new REST-related functionalities with each new release and more and more companies decide to give them a try… But how do you test them - REST services and their clients?
We live in a mobile-oriented world so it’s crucial to provide the best usability experience possible. In this post we show how you can preserve user’s context when installing a mobile application from a website.
There are two parts of this article. In first we define what is Capacity (maximum load) and Resilience (fault tolerance) of a typical e-commerce site.
This year’s edition of Strata Hadoop World held in New York was humongous, 16 workshops, over 20 keynotes, over 130 talks and most importantly over 5000 attendees! This massive crowd wouldn’t fit in Hilton hotel where the previous edition was held. That is why organizers had to move the conference to Javits Conference Center - an enormous building in which Big Data believers occupied just one sector. The fact that the European edition of Hadoop Summit experienced exactly the same transition (the third edition is going to be held in a bigger location in Brussels) gives pleasant assurance that Big Data technologies are still a hot topic and that Big Data Community grows at a stable pace.
One of new features introduced by JAX-RS 2.0 is asynchronous processing in Server and Client APIs. We use these APIs together with CompletableFuture and Java 8 lambda expressions to show how to create scalable and well performing REST services in a more functional way.
Main purpose of this article is to describe what kind of techniques may be used to build valuable and reliable products with limited time. It is based on the experiences we had, during our work on new logistics platform.
JDD conference is behind us. We had a great time doing a github dev contest (Chief Troublemaker Officer) for conference attendees. Some guys complained that the contest was too hard, good to hear! It was out intention not to make it too trivial.
If you are going to be in Kraków for JDD conference, October, 13-14th, don’t miss a perfect opportunity to meet our Allegro engineers!
