TechLab by Bol

Introduction

Another week another book discussion. Maybe we can start a second Techlab Podcast dedicated to interesting books? We got some great responses on the last week’s episode about team topologies and we had a good opportunity. So it is time for the Never Split the Difference - Podcast.

In earlier episodes, we talked with YP’s about their side projects (behind the mask - platform for the hospital to share experiences and Real-time sales dashboard), about the YP program itself and participating in competitions, the BAPC2020.

This time we sit together with representatives of the YP program because they started something really cool.

What this episode covers

The YP Bookclub. And why do I think it so cool? Because they came up with a title I wouldn’t think of Never split the difference Authors: Chris Voss Tahl Raz. Chris Voss is a former FBI hostage international kidnapping negotiator and in this book he takes you inside the world of high-stakes negotiations, revealing the skills that helped him and his colleagues succeed where it mattered most: saving lives.

So, how is this relevant to our YP’s in bol.com?

• First, we discuss the idea behind the YP Bookclub and the format.
• After that, we dive into the book and what the learnings are.
• We connect these learning to the daily job of engineers in general and Young Professionals in particular. And think about how Never split the Difference - podcast could be interesting for you.

Guests

• Priyanka Radja; Software Engineer • IT - Selling Assortment Fintech – Offer Highway
• Chris Langhout; Software Engineer • IT - Selling Assortment Fintech – Offer Highway

Notes

Akerman model – 65% of the price, 85%, 95%. Increments from big to smaller.

Black Swan Theory

Book: Socrates op Sneakers

Introduction

A lot of people involved in the design and structuring of organizations could learn a lot from the book Team Topologies. Our guest describes it in the episode a Domain Specific Language (DSL) for organizational design and evolution. The header of the website and the subtitle of the suggest that it is the way for organizing business and technology teams for fast flow.

In the episode, we discuss the 4 kind of teams and the 3 ways of interactions between these teams that are at the core of Team Topologies.

What this episode covers

Besides that, we cover the fundamental topics like Conway's Law, Cognitive Load and share examples of the use at bol.com.

Guests

• Eduardo da Silva - Space Tech Lead and sociotechnical architect

Notes

Blog post by Eduardo on Team Topologies

The book Team Topologies

Our previous podcast on sociotechnical architecture

Introduction

It sparked in the episode Interactive heavy applications we should record a podcast episode on TypeScript. Around the same time, we came in contact with Hackages. A company focusing on learning tech.

What this episode covers

Time to bring the engineers together and dive deeper into TypeScript.

Typescript is mentioned amongst the 5 most promising languages in 2020.

We talk about:

• What is typescript and how do you benefit?
• What are good implementation strategies?
  • Bol.com examples
  • Examples from Hackages
• Maturity in the usage of Typescript

Guests

• Niels van Midden; Front End software engineer at bol.com
• Davy Engone; Software Engineer at Hackages (the– The guy that is going to make you use/adapt TypeScript
• Kasper Peulen; Fullstack engineer at bol.com with focus on Front End

Notes

Refactoring your code blogpost, one of the areas typescript is being used in bol.com

Typescript home

Introduction

We want to share our approach to IT to learn and entertain you. In this episode, we are happy to have an external guest at the table discussing with our internal guest.

GraphQL stands for Graph Query Language and is used for interacting with services from the frontend. We are talking about API's here.

What this episode covers

Explore with us the possibilities this approach has to offer and how it could even help you to speeds up innovation in the front-end.

Like our guest mentions:

GraphQL is a specification not an implementationTopics

We discussed the following topics

• What is GraphQL?
• What problems does it solve?
• When should you avoid it?
• Do you need additional security measures?
• How is it used at bol.com?
• What is (a)typical for the use of this Query Language at bol.com?
• What does a development team need to get started?
• How do you document what you can query?
• What is the future?

Guests

• Albert Groothedde - Software engineer Frontmen / Rabobank used GraphQL both on front-end and back-end side at several clients
• Eduardo Gomez - Software engineer used GraphQL on the back-end side.

Notes

Falcor JS - Netflix

GraphQL vs. Falcor (Netflix)

Apollo GraphQL Data Graph Platform

Introduction

No rhythm like algorithms. We have been talking in the podcast about programming contest before. For example, about our own Spaces Championship and Advent of code, which also takes place at the end of the year.

What this episode covers

Today we’ll be talking to some participants in the BAPC - The Benelux Algorithm Programming Contest.

Like stated on the website of BAPC, it is a contest in which about 90 teams from leading universities in Luxemburg, Belgium and The Netherlands participate. The teams have to solve a series of algorithmic problems and puzzles. The BAPC 2020 was held on December 12th at the Delft University of Technology and is organized by Mathematics Informatics Study Association ‘Christiaan Huygens’

Topics discussed:

• What is BAPC2020?
  • Serious business
  • Strict rules
• Two bol.com teams competing, why?
• How is it organized? Virtual, gathering?
• What kind of problems to solve?
• Should you be an experienced SE?
• Our own bol.com spaces championship
• And the main question: will the hosts of the show compete in an upcoming championship?

Guests

• Nena O'Driscoll; Young Professional, joined several bol.com and participated in one uni programming competition before, but never the BAPC
• Bas van Rooij; Young Professional, joined several bol.com programming competition before, but never the BAPC

Notes

Scoreboard of BAPC 2020

BAPC2020 on youtube, get an idea on the live scoreboard

Blog: The Dutch Software Testing Championship

Introduction

It happens a lot that listening to a podcast sparks new questions. So, after our episode on Front-End quality, we wanted to know more about Storybook. This coincided with some people reaching out to us to collaborate in the podcast.

What this episode covers

And look where we are now: creating a new podcast on this subject. We asked our selves the question: Could it be the holy grail for front end development?

Topics discussed:

• What is Storybook?
• What problems does it solve?
• How does it support app development?
• What does the Add-on ecosystem look like?
• Is there a way to do accessibility testing?
• How do we at bol.com use this tool?
• What future developments can we expect?

Guests

• Yann Braga (twitter)- Senior Front-End Engineer at FrontMen; Contributor to Storybook.
• Niels van Midden - Front-End engineer at Bol.com in the checkout team.

Notes

The Storybook page.

The presentation at Codemotion by Yann.

Yann is building a Storybook course together with newline.co; Keep an eye on their website for the release.

Introduction

Weaving a Service Mesh for Multiple Clusters at bol.com - that was the title for the presentation our guests gave during the virtual KubeCon and CloudNativeCon 2020 earlier this year. This triggered our curiosity. We have questions like what is this service mesh about? Why do we need it? How did we implement it?.



Guests

• Remco Overdijk; Tech Lead Provisioning Fleet / Expert System Engineer at bol.com. You might know him from the episode where we spoke about Kubernetes.
• James Brook; Cloud Solutions Architect at Google

Notes

CNCF

Istio

Remco and James presenting at KubeCon/CloudNativeCon 2020

Introduction

One of the purposes of this podcast is to share our unique bol.com culture with you. Traditions play an important part in culture. So, in this episode, we share a view on the evolution of a tradition.

What this episode covers

A tradition that underlines our focus on data. In this sales season, everybody in bol.com wants to know how we are doing, preferably Real-Time. With the latest version of the Real-Time Sales dashboard, our guests managed to get the information within 100ms from sales to the dashboard.

If you are one of the people that spent maybe a little too much time watching the results of the election in the US of A unfold on CNN or another network, you could catch the bug of this tradition too. We have a magic board, but we don’t have the talking heads that came with it....

Background

In this episode, we talk about that one screen all bol.com colleagues have open all day in this season period. The initial version which was born back in 2004 and got the name Ancorama. Referring to the colleague who built it. It looked like an excel sheet being updated by querying the database. A couple of years ago a new initiative was born, Real-Time Sales. It brought great new graphs. But in fact, it still wasn't Real-Time.Now we are dealing with a brand new version and it is also known as Real-Time Sales, the next generation. Our guests had a huge stake in building this version and we want to know everything about it.

Subjects

• Why and when did you start the project?
• How did you achieve 100ms processing time?
• What building blocks used and why?
  • RSocket, R2DBC, Reactive programming, Vue3, Kotlin Coroutines
• Test approach
• Future developments

Guests

• Goos van den Bekerom; Software Engineer in the buying domain
• Marvin Zwolsman; Software Engineer in the buying domain and friend of the show! (Hey Google)
• Eugene Figueiras; Software Engineer in the Selling, Assortment and Fintech domain.

Notes

Blogpost on peak season frontend performance

Podcast on season preparations

The state of reactive streams with Oleh Dokuka

Introduction

In this episode we are sharing something that is unique at least in the Tech Community here at bol.com. To become official F/OSS committer and eventually PMC member. Without spoiling too much, I think this contribution will make a positive impact far beyond the bol.com Tech landscape and serve in an enormous number of companies. Helping engineers all over the planet.

What this episode covers

Hoping to inspire you as well to become official F/OSS committer and eventually PMC member.

Our guest is the first bol.com employee to become official committer to the Apache Logging Services. A well known, widely used Free and Open Source Software project (F/OSS). The umbrella for all kinds of logging stuff including the very well-known Log4j. And timing of the recording couldn't be better. The night before Volkan received the invitation to become PMC member. The project management committee of the Apache Logging Services project.

To become official F/OSS committer and eventually PMC member we discuss

• How he started contributing to the Open Source community
• What it needs to become contributor, spoiler: "you don't need to be a programmer".
• How he rolled into this Apache Logging Services project
• What his contribution is: JSON template layout
• The value of open source
• His thoughts of the future

(Image: https://cdn.sanity.io/images/qxrxmo3r/techlab-prd/13f626f4ab9c429055f0e188fce8970400ff5d7e-675x442.jpg)

Guests

• Volkan Yazici; Software engineer; PhD in Computer Engineering, Has been contributing to the search engine on our webshop and currently working on Axle our internal “framework” that cannot be called a framework. (check the podcast episode on Axle).

Notes

Personal projects: https://vlkan.com/code

Apache Logging Services projects: https://logging.apache.org/

unFTP: https://github.com/bolcom/unftp

Other bol.com F/OSS projects: https://github.com/bolcom

Project Management Committee as shown in the guidelines of Apache Logging Services

Introduction

Even if it doesn't appeal to you, you might want to think about it when you work in a larger microservice landscape or have a serious big data platform...Proof data consistency in a microservice landscape. When we google this subject I already get 1.2 MLN results so there’s something going on here.

To ensure data consistency several practices are available:

Saga Pattern

Reconciliation

Event Log

Orchestration vs. ChoreographySingle-Write With EventsChange-First

Event-First

Consistency by Design

Accepting Inconsistency

But in this episode, we won't go over these practices.

What this episode covers

We will dive into the verification part. The proof of the correct operation of your implementation.

Within bol.com we implemented a Data Quality Service (DQS). Actually, the second generation is already in place. The first generation focused on the immutable data in the 2nd improved version mutable data is covered as well. We will go over these questions to explain how we proof data consistency in a microservice landscape:

• How did we come up with our solution?
• What is our approach?
• How does it relate to our big data, BigQuery storage?

Statements

As a starter, we discuss these statements first

• Why care it is just data...
• The microservice is not the issue, the independent data storage solution is, so let’s get back to the centralized databases (makes testing also a lot easier)
• An architect should be the guest of this show as it’s part of his/her role to fix this
• Data Consistency is not a problem for Software Engineers. It should be fixed by our infrastructure solutions

Guests

• Mykola Gurov – Of course, you all know him since he was in our very first episode about Kotlin. Or otherwise from one of his testing in production talks. Jack of all trades.
• Chris Gunnink – Software Engineer on a crusade - DQS
• Sourygna Luangsay – Tech Lead in experimentation, forecasting and the finance product a lot more products

Notes

Bigquery - bol.com adoption story

BigQuery - Google’s Data warehouse running in the Google Cloud Platform (GCP)