Modern Go on

Lesson 5: What's New in Go 1.25–1.26 — Swiss table maps, weak pointers, and the future

Sun, 02 Mar 2025 00:00:00 +0000

Every major Go release follows a rhythm: one or two headline language features, a handful of standard library additions, and a runtime improvement you probably do not notice directly but that makes your services run better in aggregate. Go 1.23 and 1.24 brought the iterator protocol, go tool improvements, and the unique package. Go 1.25 and 1.26 continued this pattern with Swiss table map internals, a production-ready weak pointer API, and improvements to the toolchain that affect how you build, ship, and profile Go binaries.

Lesson 4: Structured Logging with slog — The stdlib logger Go always needed

Thu, 12 Dec 2024 00:00:00 +0000

I have switched logging libraries in Go more times than I care to admit. Started with the standard log package — fine for scripts, useless in production because you cannot query plain text logs efficiently. Moved to logrus because everyone was using it. Switched to zap when I needed better performance. Considered zerolog when I wanted allocation-free hot paths. Each migration meant updating every file that imported the old library, convincing teammates, and writing bridge adapters for third-party code that used a different logger.

Lesson 3: Loop Variable Fix — The Go 1.22 change that fixed a decade of bugs

Sun, 13 Oct 2024 00:00:00 +0000

If you have written Go for more than a few weeks, you have hit this bug. Or you have reviewed code that had it and caught it. Or — if you were unlucky — you shipped it to production and spent an hour staring at a data race report wondering what on earth was happening. The loop variable capture bug was so common that it was essentially a Go rite of passage. Every Go tutorial mentioned it. Every linter had a rule for it. And for a decade, the answer was always “just copy the variable inside the loop.”

Lesson 2: Enhanced HTTP Routing — Method patterns in net/http, no more gorilla/mux

Sun, 11 Aug 2024 00:00:00 +0000

For most of my Go career, the standard library’s net/http.ServeMux was something I used for toy services and immediately replaced with gorilla/mux for anything real. The standard mux could not match HTTP methods. It could not extract path parameters. It matched prefixes in ways that surprised people. The moment a production service needed GET /users/{id} and POST /users, you reached for a dependency.

Go 1.22 changed that. The enhanced ServeMux now supports method matching, wildcard path parameters, and precedence rules that actually make sense. I rewrote three internal services to drop gorilla/mux after reading the release notes, and every one of them got shorter and simpler. This lesson covers exactly what changed and when you still might want a third-party router.

Lesson 1: Range Over Integers and Iterators — for i := range 10 and the iterator protocol

Tue, 04 Jun 2024 00:00:00 +0000

I have written for i := 0; i < n; i++ so many times that my fingers type it on autopilot. The three-clause for loop is fine — it works, everyone understands it, and Go has always had it. But when Go 1.22 shipped for i := range 10, I stopped and stared at it for a moment. Not because it was complicated. Because it was so obviously the right thing that I wondered why it had taken this long.