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Go

Go is an open source programming language that makes it easy to build simple, reliable, and efficient software.

Installation​

You can follow the official instructions on how to install Go, or you can use Homebrew instead:

brew install go

When installed, run go version to see the installed version of Go.

$ go version
go version go1.11.4 darwin/amd64

Setup your workspace​

The GOPATH and PATH environment variables​

The GOPATH environment variable specifies the location of your workspace. It defaults to a directory named go inside your home directory ($HOME/go).

If you really want to change your GOPATH to something else add GOPATH to your shell/bash/zsh initialization file .bash_profile, .bashrc or .zshrc.

export GOPATH=/something-else

Add GOPATH/bin directory to your PATH environment variable so you can run Go programs anywhere.

export PATH=$PATH:$(go env GOPATH)/bin

Make sure to re-source source .bash_profile your current session or simply open new tab within iTerm.

Write your first program​

Create a file in your workspace $GOPATH/src/hello/main.go and add some code, for example:

package main

func main() {
    println("Hello World!")
}

Run the program by running:

$ go run hello.go
Hello World!

If you wish to compile it and move it to $GOPATH/bin, then run:

go install .

Since you have $GOPATH/bin added to your $PATH, you can run your program from anywhere:

$ hello
Hello World!

Import a Go package​

Besides creating your own packages you can import and use other packages in your Go code. To do so you'll use the go get command:

go get -u github.com/gorilla/mux

The command above will import the package mux into this directory $GOPATH/src/github.com/gorilla/mux.

You can then use this package in your Go programs like this:

package main

import (
    "github.com/gorilla/mux" // Your imported package
    "net/http"
)

func yourHandler(w http.ResponseWriter, r *http.Request) {
    w.Write([]byte("Gorilla!\n"))
}

func main() {
    r := mux.NewRouter()
    // Routes consist of a path and a handler function.
    r.HandleFunc("/", yourHandler)

    // Bind to a port and pass our router in
    panic(http.ListenAndServe(":8000", r))
}

Tooling and learning​

Format your code​

Go has a built-in tool that automatically formats Go source code.

To format a single file run:

gofmt -w yourcode.go

You can also format an entire package:

go fmt path/to/your/package

Note: that the command is different from formatting a single file

Generate documentation​

With the godoc command you can generate documentation from your code and read documentation from other packages.

godoc fmt                # documentation for package fmt
godoc fmt Printf         # documentation for fmt.Printf
godoc -src fmt           # fmt package interface in Go source form
godoc -all -http :1234   # documentation for all packages on your machine served through http http://localhost:1234

You need to respect some spec in order to document using godoc. More information in the Godoc documentation.

Learn more​

The interactive tutorial will let you learn more about Go. You can also install it locally by go get golang.org/x/tour and running it anywhere by tour (given that you added GOPATH/bin to your PATH).