Go Before You Wait • The Applied Go Weekly Newsletter 2025-06-22
Your weekly source of Go news, tips, and projects
Go Before You Wait
Hi ,
The smallest improvements are sometimes the best, as in the sync package that receives a new WaitGroup method in Go 1.25. The new Go() method isn't just small at the surface, it's implemented in a handful of lines of code.
Small is beautiful, don't you think, too?
–Christoph
Featured articles
The Small Change That Made a Big Impact - Compa Compila
When your code is slow and the main logic is not the culprit...
Writing Load Balancer From Scratch In 250 Line of Code
The best option for learning how a load balancer works is to implement one. The second-best option is to read an article that explains how the author implemented a load balancer.
Gist of Go: Race conditions
Races are only fun if humans, animals (rats excluded(*)), or vehicles are involved. They cease to be fun if goroutines get into a race on accessing data. Luckily, the book Gist of Go (a work in progress) got a chapter about race conditions.
(*) Why? Because if you win a rat race, you're still a rat.
Podcast corner
Cup o' Go: Agentic workflows and AI firewalls, so pretty much cancelling ourselves out
Listen closely—don't the voices of Jonathan and Shay sound AI-generated?
Well ... probably not.
Fallthrough: Go's Error Handling Is Handled
A recent Go Blog post made it clear: Go's error handling remains as it is. Kris, Ian, and Matt think it's fine, and so do I, and so do you?
Spotlight: New in Go 1.25: WaitGroup.Go()
This is an improvement many of you will love. It is a usability enhancement along the lines of testing's b.Loop() that did away with a clumsy loop condition (and made benchmarking more efficient) in Go 1.24.
I'm talking about WaitGroup.Go(). Starting with Go 1.25, you no longer need to call Add(1) for each goroutine spawned inside a WaitGroup and hope that there's no mismatch with the number of calls to Done().
With Go 1.25, using a WaitGroup is as easy as:
var wg sync.WaitGroup
for i := 0; i < 3; i++ {
wg.Go(func() {
// do something
})
}
wg.Wait()
How is Go() implemented? This is easy to find out, and that's one of the many bits that I love about Go: In the documentation of a Go package on pkg.go.dev, you can click on the title of any identifier (function, type, etc.) to open its source code in Go's official repository. If you drill down on the Go() method, you'll discover that the implementation of WaitGroup.Go() is refreshingly simple; it's just a thin wrapper over the "old" style:
func (wg *WaitGroup) Go(f func()) {
wg.Add(1)
go func() {
defer wg.Done()
f()
}()
}
Go() simply does the Add()/Done() bookkeeping under the hood for you. Neat!
Quote of the Week: The proof is in the pudding user
Go change the way of thinking and the proof is the people who are using Go or people who are just switched from other languages like me. No language is perfect but Go is closest to perfect.
More articles, videos, talks
OpenTelemetry for Go: measuring the overhead | Coroot
OpenTelemetry enables a server to collect and submit metrics, logs, and traces—but what is the cost? Nikolay Sivko measured the performance overhead of OpenTelemetry in a high-load Go application.
Parsing, Not Guessing | Francis Sunday
Regular expressions are powerful but frequently overused. They become complex very quickly and then are a royal PITA to debug. (Hint: sites such as regex101.com are your friend.) Markdown is a good example of a language that shouldn't be "parsed" with regular expressions. It's much better to parse a Markdown text into an abstract syntax tree (AST). Francis Sunday demonstrates how the goldmark package exposes an AST of a rendered Markdown text that can be easily traversed for rendering purposes.
The joy of (type) sets — Bitfield Consulting
With the introduction of type parameters in Go 1.18, interfaces were no longer just "lists of functions" but expanded into a means of constraining the set of allowed types for a type parameter. John Arundel explores the possibilities.
Introducing Chess V2: A New Chess Library in Golang
Uh—what does a chess library do? Specifically, brighamskarda/chess? It can generate legal and pseudo-legal moves from a given board status, parse positions in FEN notation, parse moves in SAN or UCI format, check positions for checkmate or stalemate, and then some.
Statically and dynamically linked Go binaries - YouTube
Go binaries are statically linked, until they aren't. Alex Pliutau explores the differences.
Optimizing calling Windows DLL functions in Go
If you need to call functions in Windows DLLs, you'd go with sys/windows ... unless there is a smarter way.
Unexpected security footguns in Go's parsers
When reading this article, keep this comment from Jeremy Bowers in mind:
"There's a lot of good information in there but I find the tone alarmist. Much of that is user error with plenty of analog in basically every other language. Variations in JSON parsing are everywhere, there is not One True Standard that if you deviate from it you are presumptively In Violation and can be blamed. There's just too much variation for that. JSON issues in a lot of other languages abound, and some are just endemic to the format. The real problem is just that these standards are not as safe as their ease-of-use may imply."
Projects
Libraries
GitHub - floatdrop/debounce: A zero-allocation debouncer written in Go.
"Call this function, but don't call it too often!" This debouncer delays a function call until the function hasn't been called in a specified time and then runs it; all prior calls get dropped. Debouncing can be useful for rate limiting and reducing redundant calls of functions.
GitHub - nlpodyssey/openai-agents-go: A lightweight, powerful framework for multi-agent workflows in Go
The OpenAI Agents SDK is for Pythonistas only, but here is a port for Gophers!
GitHub - john-marinelli/panes: A Bubble Tea component for creating multi-pane applications
A multi-pane application in your terminal? No problem with Bubble Tea and john-marinelli/panes.
GitHub - charmbracelet/fang: The CLI starter kit
There is virtually no way around the Charm packages for developing terminal UI (TUI) apps. Now Charm has a new (still experimental) package: Fang, a layer on top of Cobra that aims to make starting a CLI app even easier.
Tools and applications
GitHub - firstrow/mcwig
Vim in Go? For a toy project, McWig has quite a few features already, including "lots of bugs". The author plans to develop this proof of concept into a full editor.
GitHub - yokecd/yoke: Kubernetes Package Management as Code; infrastructure as code, but actually.
Sick of templating yaml with yaml for Kubernetes package management? With Yoke, you can write resource description in the language you love—which is probably Go, but any language that compiles to WASM should do.
GitHub - goptics/vizb: An interactive go benchmarks visualizer
How do you turn benchmark outputs into interactive HTML charts? With a single command.
Go Struct Analyzer
Optimizing struct memory usage has become easier. Go Struct Analyzer is a VSCode package (also available on Open-VSX) for uses of VSCodium and other VSCode derivates) that augments struct fields with their sizes, and alerts the user about optimization opportunities.
Completely unrelated to Go
Reinvent the Wheel
Don't reinvent the wheel—or rather, do! Matthias Endler knows why reinventing things is actually quite good for everyone.
Rolling the ladder up behind us
With LLMs reaching the level of a junior developer, companies may be tempted to stop hiring juniors as the LLM do the same stuff but cheaper. Xe Iaso explains why this is a footgun.
Happy coding! ʕ◔ϖ◔ʔ
Questions or feedback? Drop me a line. I'd love to hear from you.
Best from Munich, Christoph
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