Understand Custom Types

In addition to the built-in data types provided by Go, you can create your own custom types to better represent specific concepts in your application. These custom types can enhance code readability, maintainability, and type safety.

Custom Types and gRPC

Custom types are particularly useful in the context of gRPC, where you often need to define complex data structures to represent request and response messages. By creating custom types, you can encapsulate related fields and provide meaningful names, improving the overall clarity of your gRPC services.

Creating Custom Types

You can create custom types using the type keyword and a descriptive name. Here are some common types you might encounter:

1. Aliases

Aliases create a new name for an existing type. This can improve code readability and maintainability.

Go

type Age int
type Name string

2. Structs

Structs group together related fields of different types. They are commonly used to represent complex data structures.

Go

type User struct {
    ID   string
    Name string
    Age  int
}

3. Interfaces

Interfaces define a set of methods that a type must implement. This allows you to define contracts and create polymorphic behavior.

Go

type Shape interface {
    Area() float64
}

type Rectangle struct {
    Width  float64
    Height float64
}

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

4. Enumerations

Enumerations (enums) define a set of named constants. They are useful for representing a fixed set of values.

Go

type Color int

const (
    Red   Color = iota
    Green Color = iota
    Blue  Color = iota
)

5. Type Assertions

Type assertions allow you to check if a value is of a specific type.

Go

var shape Shape = Rectangle{Width: 5, Height: 10}

if rect, ok := shape.(Rectangle); ok {
    fmt.Println("Area:", rect.Area())
}

Custom Types in gRPC

Custom types can be used to define request and response messages in gRPC. By creating well-defined custom types, you can improve the readability and maintainability of your gRPC services.

Example:

Protocol Buffers

message User {
  string id = 1;
  string name = 2;
  Age age = 3;
}

enum Age {
  UNKNOWN = 0;
  CHILD = 1;
  ADULT = 2;
}