Book review: The Go programmming language

Some books are so good you feel honored to be able to read them, and “The Go programming language”, in my opinion, happens to make that list: it’s a real gem.

Now, I can’t really tell if it’s because I personally like Golang a lot or because the author is some kind of Stephen King of technical writers, but I must admit this was one of the best books I’ve ever read: the way it guides you through the language, explain design decisions, common pitfalls (and how to avoid them) and so on is simply beautiful.

To give you a perspective, the book is very practical, and each chapter kind of adds a feature to the software you’re building:

To me, reading the book just feels like entering Rob Pike’s brain to understand the decisions and rationale behind Go’s design, standard library and so on.

(side note: Rob Pike actually reviewed the book. As soon as I found out, I got quite excited!)

As someone who has been playing with the language for 2 years but didn’t deploy more than 2 real-word Go apps in production, it was definitely a good read, so I’d encourage mid, novice and aspiring Golang programmers to read the book.

Keeping in mind that I tend to be excited about Golang in general, here’s a bunch of significant quotes from the book:

creating one goroutine is cheap and creating a million is practical

go doc http.ListenAndServe

There is no limit on name length, but convention and style in Go programs lean toward short names, especially for local variables with small scopes; you are much more likely to see variables named i than theLoopIndex. Generally, the larger the scope of a name, the longer and more meaningful it should be.

normal practice in Go is to deal with the error in the if block and then return, so that the successful execution path is not indented

Get into the habit of considering errors after every function call, and when you deliberately ignore one, document your intention clearly.

the unit of encapsulation is the package, not the type as in many other languages.

The entire errors package is only four lines long

When designing a new package, novice Go programmers often start by creating a set of interfaces and only later define the concrete types that satisfy them. This approach results in many interfaces, each of which has only a single implementation. Don’t do that. Such interfaces are unnecessary abstractions; they also have a run-time cost. You can restrict which methods of a type or fields of a struct are visible outside a package using the export mechanism. Interfaces are only needed when there are two or more concrete types that must be dealt with in a uniform way.

A defer is marginally more expensive than an explicit call to Unlock, but not enough to justify less clear code. As always with concurrent programs, favor clarity and resist premature optimization. Where possible, use defer and let critical sections extend to the end of a function.

Be descriptive and unambiguous where possible. For example, don’t name a utility package util when a name such as imageutil or ioutil is specific yet still concise.

Good documentation need not be extensive, and documentation is no substitute for simplicity.

Go’s attitude to testing stands in stark contrast. It expects test authors to do most of this work themselves, defining functions to avoid repetition, just as they would for ordinary programs.

As the influential computer scientist Edsger Dijkstra put it, “Testing shows the presence, not the absence of bugs.”

Since other goroutines cannot access the variable directly, they must use a channel to send the confining goroutine a request to query or update the variable. This is what is meant by the Go mantra “Do not communicate by sharing memory; instead, share memory by communicating.”

Go is really magical, the kind of magical that makes you productive and leaves you speechless1 when writing code.

  1. Note: not the PHP kind of speechless ;-)
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