January 29, 2024

Deploying to EMR Serverless via EMR CLI

Recently as part of my academic studies I had to deploy a PySpark application to EMR Serverless. I encountered a couple of issues along the way - most of them related to me trying to get a newer version of Python running on the cluster. This post will cover the issues I encountered and how I resolved them. Read more

February 25, 2023

Defer your mutex Unlocks

A few weeks ago we had an incident where our RabbitMQ was blocked and no new messages were processed. Restarting the service temporary resolved the issue, but the underlying the problem was still there. It was caused by a mutex that stayed locked after a panic. Even though we did recover from panic - the mutex remained to be locked. Read more

August 3, 2022

Easy memory-saving tricks in Go

Unless you’re prototyping a service - you probably care about the memory usage of your application. With a smaller memory footprint, the infrastructure costs are reduced and scaling becomes a bit easier/delayed. Even though Go is known for not consuming a lot of memory, there are ways to further reduce the consumption. Some of them require lots of refactoring, but many are very easy to do. Read more

July 27, 2021

Glice v2 - Adding support for go.mod

Glice has been the first open-source project I published on my GitHub account. It’s a dependency checker for Go that used to go through all .go files, parse the imports and fetch the licenses for third-party dependencies. Long overdue I’ve added support for projects using Go Modules and did a major refactor simultaneously. Read more

April 14, 2021

HTTP logging in Go

Having good logging is crucial for running and debugging applications in production. It reduces your issue to resolution time by providing details about every action, request, and response. Designing a good logging system isn’t a trivial task, and requires an eye for detail. Here’s how I do it in Go! Read more

February 17, 2021

Removing null values from maps or JSON with Go

Recently I was given a task of removing all keys that have null values from an arbirtrary json. We do data processing of Excel/csv files and have default config generated for them server-side. Users provide custom configuration (column types, names, headers, sorting …) and these two get merged. Problem was - if key existed and had null value it would override the key that had a value. Obviously there may be other ways to do this, but this is a very generic solution that can be used in most cases. Read more

August 2, 2020

A robust RabbitMQ client in Go

A few months ago I started working on a project that heavily relies on RabbitMQ as a message broker. We have two clients communicating with Go, one via AMQP (RabbitMQ) and the other through HTTP. As our dependency on RabbitMQ is big, I had to write a robust client that does graceful shutdowns, panic recoveries, is multithreaded, logs everything nicely, and more. Read more

May 23, 2020

Pushing data upstream in Context

Go’s context is a hefty tool that was added as an official package back in 1.7. The context package provides contextual information that a goroutine may need such as how long it should run and how and when it should end. It can also pass informational key-value pairs for use down the call chain. But what if we need to pass information up in the call chain? Pointers come to the rescue. Read more

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