Master Go Programming: The Complete Go Bootcamp

GOPATH and Code Organization

• Go requires you to organize your code in a specific way

• Go programmers typically keep all their code in a single workspace

• A workspace is nothing more than a directory in your file system whose path is stored in an environment variable called GOPATH

• On windows, it's in %USERPROFILE%\go

• On Macs & Linux, it's in ~go

• You can print out the values of the environment variables by running the go env command

Go Workspace (GOPATH)

The work directory (GOTPATH) contains the following 3 subdirectories at its root:

1. src: contains the source files for your own or other downloaded packages

2. pkg: contains go package objects (aka package archives)

   • these are non-executable files or shared libraries ending in .a

3. bin: contains compiled & executable Go programs

   • when you run go install on a program directory, Go will put the executable file under this file

• To run/compile programs (CLI): go run <filename.go>

Compiling (go build) & Running Go Applications (go run)

go is a tool for managing Go source code

1. go run: compiles & runs the application

   • it doesn't produce an executable

   • go run <filename.go> compiles & immediately runs the Go program

   • go run -x <filename.go> gives details about the compilation process

2. go build: it just compiles the application

   • produces an executable

   • go build <filename.go> compiles a bunch of Go source files

   • compiles packages and dependencies

   • go build will compile the files in the current directory and will produce an executable file with the name of the current working directory

   • go build -o app produces an executable file called app

• compiling for windows: GOOS=windows GOARCH=amd64 go build -o winapp.exe

• compiling for linux: GOOS=linux GOARC=amd64 go build -o linuxapp

• compiling for mac: GOOS=darwin GOARCH=amd64 go build -o macapp

3. go install

• both go install & go build will compile the package in the current directory

• if the package is main, go build will place the resulting executable in the current directory and go install will move the executable to GOPATH/src

Formatting Go Source Code (gofmt)

• Go strongly suggests certain styles

• gofmt which comes from golang formatter will format a program's source code in an idiomatic way that is easy to read and understand

• gofmt is built into the language runtime and it formats Go code according to a set of stable, well-understood language rules

• can be run manually at the command line or can configure our IDE to rub gofmt each time a file is saved

Example: gofmt -l -w main.go

• -l: tells you which file was modified

• -w: if not formatted correctly, will overwrite file

• if you run gofmt in the directory, all source files will be formatted correctly

Variables in Go

• a variable is a name for a memory location where a value of a specific type is stored

• a variable belongs and it's created at runtime

• a declared variable MUST be used or get an error!

• _ is the blank identifier and mutes the compile time error returned by unusual variables

Declaring variables:

1. using the var keyword

2. using the Short Declaration Operator (:=)