Blog – 96 articles

Building an Engineering Culture

Peter Paul van de Beek, Peter Brouwers, on 8-04-2021
Category: Blog, Development Tags: Community Agile Innovation skills Culture Video Engineering Culture Diversity

In the bol.com Tech Community, we get quite some questions on how we build a great engineering culture. Mid-March 2021 the hosts of our podcast joined the Hackages podcast which was live recorded with almost 100 attendees. They shared their experiences and answered many questions from the audience. Hackages is a community based platform to help developers and businesses grow and empower each other through content, training and consultancy services In bol.com we believe that autonomy of the teams brings the creativity, knowledge and craftmanship needed to build the leading…

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Know what you deploy – a script using git log for listing all features that go live

Nick Tinnemeier, Dennis de Bode, on 19-03-2021
Category: Blog, Development Tags: git shell script git log automate deploy list features that go live

Introduction For me, even after having pushed the deploy button many times, deploying to production keeps being dreadful. Accidentally pushing an unwanted feature that sneaked in somehow is one of the many things I am afraid of. In this blog post I show you how we reduced our deployment anxiety with a script using git log for listing all the features that go live after pushing that deploy-to-pro button. In this blog post I first introduce you to the way we work and provide you with the necessary information to…

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HPA: how it can save you headaches and money

Alexandra Egher, on 12-03-2021
Category: Cloud, Development Tags: cloud kubernetes gcp hpa google shopping

In this blog, we show you how to automatically scale your application resources according to either the CPU consumption or to the incoming load of your application.  Background As humans, we are capable of adapting to variable inputs and situations. Some of us are slower, whereas others easily adapt to change. In dynamic environments, flexibility has become one of the most valued skills. As engineers, we also thrive for adaptability. We embrace new technologies, new responsibilities, and new ways of working together. We want to build future proof solutions that react quickly…

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Product Development for Data Science – From Idea to Production in 7 Phases

Simon Stiebellehner, on 26-02-2021
Category: Data Science & AI, Development

Towards the end of 2020, Melissa Perotti and I held a talk on Product Development for Data Science Products at GoDataFest – the (this time virtual) festival of Data Technology. We elaborate on how we follow a 7-phase process to take Data Science projects from idea to prototype and from prototype to production.   About the talk In every industry, a remarkably large share of Data Science (DS) projects fail. There are various reasons why DS projects may come to a halt:  Data quality or size is insufficient,  the model doesn’t…

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Moving to the cloud? Don’t let your application become a downer!

Richard Deurwaarder, on 12-02-2021
Category: Blog, Cloud, Infrastructure, Development Tags: Resilience cloud kubernetes gcp

Introduction At bol.com we have two main ways of running our applications. We can deploy them in a Datacenter (DC) managed by us or we can run them on Google Cloud Platform (GCP). Many applications are being migrated from DC to the GCP to take advantage of the different products available in GCP. Switching to the cloud isn’t just a matter of lift ‘n shifting your application though, there are several changes that you should take into account. One of those changes is, how the behavior of the underlying platform…

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How to map optional fields with MapStruct

Nick Tinnemeier, on 5-02-2021
Category: Development Tags: mapping MapStruct Java Optional mappers

Introduction MapStruct is a framework that alleviates us, programmers, from the unexciting task of writing code to copy one object model to another, field by field. In this blog we show you how to map optional fields with MapStruct. If, after reading this, you still wonder what MapStruct is and what it can do for you, then this blog could answer those questions for you: https://techlab.bol.com/mapping-object-models-case-study/. This blog zooms in on MapStruct’s capabilities of dealing with source fields that are not always present, i.e. might be null. In particular, we…

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How to write MapStruct mappers for object hierarchies

Nick Tinnemeier, on 1-02-2021
Category: Development Tags: Java mapping MapStruct hierarchies inheritance object hierarchies class hierarchy

Introduction MapStruct is a framework that alleviates us, programmers, from the unexciting task of writing code to copy one object model to another, field by field. This blog elaborates on how to write MapStruct mappers for object hierarchies. If, after reading this, you still wonder what MapStruct is and what it can do for you, then this blog might be a good read: https://techlab.bol.com/mapstruct-case-study/. To already spoil the fun, MapStruct is not able to generate mappers for classes that all inherit from the same (abstract) base class or interface. In…

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Mapping object models with MapStruct – a case study

Nick Tinnemeier, on 6-01-2021
Category: Development Tags: Java MapStruct mappers mapping object models converters code generation

Introduction I was once told that a good programmer is a lazy programmer. A good programmer avoids typing tedious code, where the code could basically write itself. Self-writing code – wouldn’t that be great? Unfortunately, we’re not quite there yet. We show you how close to self-writing code you can get. In this blog we will present a case study using MapStruct for mapping object models. In particular, we zoom in on how the MapStruct framework alleviates us from the dull task of writing code to copy one object model…

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A look back at 2020 podcasts

Peter Brouwers, Peter Paul van de Beek, on 29-12-2020
Category: Blog

Time to reflect on season 2 of the bol.com techlab podcast with Peter Paul van de Beek  and Peter Brouwers. Thanks for all the support in 2020 and we love to see you back in 2021 as guest and listener, Happy New Year!  

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Spaces Talk #6: Making Demos Great Again

Marloes Kuijper, on 19-10-2020
Category: Data Science & AI, Events Tags: Event Machine Learning Spaces Summit data science demo

At this year’s Spaces Summit, I presented a talk on Streamlit: a new web application framework in Python, which is perfect for making data science demos. About the talk As Data Scientists, we often need to quickly prototype ideas and showcase those projects to the business. Yet, Python scripts are not very visually appealing and Powerpoint is not always suitable. You also don’t want to spend weeks setting up that throw-away, unmaintainable Flask application, just for the purpose of showcasing your idea. Fortunately, there’s a solution to all of these…

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