Golang | Braindump

Why was Go created?

efficient compilation
easy to code
efficient execution

Project Structure

Not a hard rule, but based on common conventions.

.
|-- go.mod
|-- readme.md
|-- tests
|-- cmd
|   |-- app
|       |-- main.go
|-- internal
|   `-- module1
|       `-- module1.go
`-- pkg

go.mod
readme
cmd
- a

Useful Libraries

air: automatic recompile and run

Modules

variables and functions are private to the package, but can be accessed in different files without importing IF they are in the same package and folder
public variables and functions start with a capital

Control Structures

Conditionals

There's a special if/else structure where you can declare a variable that's in-scope for only the if/else. Not really a thing in most languages.

if message := "hello"; user != nil {
	// message available
} else {
	// message available
}

Loops

There's only for, no do-while, no while

Interface

You only need to define the methods for each struct in order to implement the interface. So for example, if you have the following Rectangle.

type Rectangle struct {
    Width, Height float64
}

func (r Rectangle) Area() float64 {
    return r.Width * r.Height
}

func (r Rectangle) Perimeter() float64 {
    return 2 * (r.Width + r.Height)
}

If in the same package, an interface is defined like so.

type Shape interface {
    Area() float64
    Perimeter() float64
}

This, implicitly means that the Rectangle implements the Shape interface. Meaning, that you can pass in Rectangles to functions which expect a Shape.

func PrintShapeDetails(s Shape) {
    fmt.Printf("Area: %f, Perimeter: %f\n", s.Area(), s.Perimeter())
}

func main() {
    r := Rectangle{Width: 10, Height: 5}
    PrintShapeDetails(r)
}

Concurrency

For now, I understand goroutines as just creating a lightweight thread, which means that whatever function is called in the goroutine will running separately from the rest.

Read Tour of Go - Concurrency

Testing

When testing you can use the package packageName name itself, when you are testing internal functions. If you'd like to test from a package consumption perspective you opt for package packageName_test.

References

How to Start?

How to gain deeper knowledge?

Effective Go