bkielbasa/developer20

Bartłomiej Klimczak	[email protected]
Technologies	Go, Kubernetes, Docker, AWS, MySQL, PostgresSQL, Kafka
Distinctions	Google Developer Expert in Go category

• My personal blog
• Twitter account: kabanek

Blog posts

• Top level logging
• replace directive in go modules
• gRPC with SSL/TLS
• How to structure Go code?
• HTTP context livetime

Experience

Go developer at G2A

(July 2020 - June 2021)

I'm building the logistic part of the platform. I build Go (micro)services that support purchasing a physical product as well as integrating with external services. One of my challenges was understanding the domain correctly to be able to rewrite the monolith (Magento) application. I had to make sure that, at the first phase, the behavior doesn't change but the new implementation is open to new features and improvements. I modeled the part of the domain I was responsible for.

What's more, I was a member of a team that introduced OpenTelemetry in the company. I prepared a Go library helped developers to migrate to the new solution.

Technologies I use: Go, Kubernetes, Docker, RabbitMQ, Kafka, ELK

Go developer at Brainly

(May 2018 - July 2020)

I've been working in a team that focused on engaging users to have more interaction with the page. I built several services that support it. One of them was a service that's tracking user's pageviews (similar to Google Analitycs). The value it brought was associating specific page views with concrete users. It gave us the ability to create very targeted campaigns.

Technologies I use: Go, Kubernetes, Docker, RabbitMQ, GraphQL, ELK, AWS

Senior PHP developer at FreshMail

(July 2016 - May 2018)

I've been part of the core team that builds the e-mail marketing platform. One of my responsibilities was maintaining the legacy code.

Technologies I use: PHP, MySQL, AWS

PHP developer at Integer (InPost)

(February 2014 - July 2016)

I built a "Manager Paczek" (Parcels Manager). It's a tool for retail customers. They can create and manage their parcels (pay for shipment, notify addressee via sms/email etc). I was building the backend for the whole solution.

Technologies I use: PHP, MySQL

PHP developer at Polcode

(July 2011 - July 2014)

It was a freelance possition where I've been working on building web sides based on Magento, Wordpress, Joomla and so on. My responsibilites was contacting with clients, gathering requirements and developing the webside.

Technologies I use: PHP, MySQL, JS

Projects

I'm a huge fan of opensource so I have my own projects that support the community :)

• https://developer20.com/ - It’s my blog where I share my knowlage with others. I focus on Go development but you can find much more there
• GoBDD - BDD framework for Go. It’s goal is to give as simple and powerful BDD framework for Go.
• Cyclop - It’s a tool which analize Go code and caluclates its cyclomatic complexity
• GoCracow and Golang Poland - Local meetup focused on Go. I lead the community as well as give talks.

Hobby

• I like playing Dota2 and chess
• I learn to play ukulele (but I'm just a beginner)

developer20's Issues

“Transaction management” (e.g. with repository pattern)

Links:

• https://audrenbdb.fr/posts/repo-transaction/
• https://zenidas.wordpress.com/recipes/repository-pattern-and-transaction-management-in-golang/
• https://blog.devgenius.io/go-golang-clean-architecture-repositories-vs-transactions-9b3b7c953463

Pls don't mock `sql.DB`!

Programs you should know how to develop before applying for Go role

Writing custom marshaler and unmarshaler in Go

Profiling Go applications

Interfaces naming convention

Fuzzy testing in Go

write simple event store in Go

Add dark theme

My VIM setup for Go

How to debug a Go Application in Kubernetes from IDE

Go scheduler

Customizing Go Binaries with Build Tags

Six types of decaupling

My most common PR comments

Top 5 design patterns

There are many design patterns. In this art, I'd like to describe those that I use the most.

Finding goroutine leaks

Add example error output

to this post: https://developer20.com/golang-tips-and-trics-vii/

this will help to find this post by googling the error message

E-commerce app written in Go with DDD and clean architecture in mind

How to debug `init()` functions

https://pkg.go.dev/runtime

Understanding sync.mutex package

How to design better API

Cancellable `io.Reader`/`io.Writter`

by default, all io.Reader and io.Writer aren't cancelable. It's quite simple to add it to them. In this blog post, I'll describe a few ways of doing it.

Why you should aim to deploy of friday at 16:00

but not necessarily to do it :)

Understanding stack/heap and anything related to allocations in Go

• What's the difference between heap and stack?
• When does Go allocate to the heap and when to the stack?
• How to measure it?

Golang and Event-Driven Architecture

Error handling in Go

Write CQRS implementation in one table

DNS server in Go

Create a gif on-the-fly that never ends.

It's possible to create a GIF file that's infinite. If we make it on the fly, we can basically stream a video.
The project's goal would be to show this feature in a project written in Go. It doesn't have to be video streaming but a simple infinite GIF file.

Golang for haters

There are a ton of articles/talks that complain about Go. Sometimes they are right. Sometimes don't. In this article, I want to take a look at all of their arguments and try to explain or say if they are right or not.

Sounds fun!

How to use tracer in Go

Using delve

how I write web apps after 5 years in Go

How to make tests more readable?

Describe good practices with working with tests. Avoid globals and use builders or named parameters instead.

More in-depth analize of `fmt` package

Different concurrency patterns

When goroutines, we have multiple ways we can handle the concurrency. We can use context package, sync package, or patterns like Fan-in and Fan-out/pipeline/actors.

In this series (?) of articles, I want to describe most of them with their pros and cons.

More in-depth analize of `testing` package

Micro and macro optimizations in Go

How GC in Go works

GC Semantics, Write barriers, alghoritms

You cannot hire a senior

a bit of philosophical article :)

Create twitter card

Validator: https://cards-dev.twitter.com/validator
And docs: https://developer.twitter.com/en/docs/tweets/optimize-with-cards/overview/summary

Don't use env vars in k8s

Questions and answers for the most popular interview questions (for gophers)

Describe different concurrency patterns in Go

Pros and cons of using monorepo

Write DNS server in Go

than can be funny!

refs: https://blog.adamchalmers.com/making-a-dns-client/

Memory layout, CPU caches and Go

SOLID in tests

Draft PR here: #38

Garbage Collector in Go