It serves as a great reference, the code in there runs with small changes, I know this because I ran the code myself when I was contemplating adding content from this book to my own FOSS ebook (https://github.com/thewhitetulip/web-dev-golang-anti-textboo...), I emailed the Professor and he gave his permission, but I skipped on adding chapters because this book itself was available via the author's home page and there was no point in me adding it to my tutorial, I am glad this is now available via gitbooks!

Since Go is backward compatible, it is in the contract somewhere, you can refer this book even though it was written a long long time ago!

Go hasn't changed much cosmetically since 2012.

I had the same question, but so far the answers here are from a "technical correctness" perspective (which isn't a concern since Go is good at compatibility).

My question is whether newer libraries and best practices have evolved since 2012, or if the ecosystem has remained static in this area since 2012. I'd certainly hope there's been some learning since then, unless Go really had already achieved perfection the first time around; color me skeptical.