go get github.com/pioz/faker

faker.SetSeed(623)

fmt.Println(faker.Username())
fmt.Println(faker.String())
fmt.Println(faker.IntInRange(1, 10))
fmt.Println(faker.CurrencyName())
// Output: spicule
// gzaazJyRGt3jDnVh6ik7R9FO0AU1HcOzdOXbmNVBRQ5pq8n9tHf9B21PIFozLEzsoY4wILvZjTxSLQmD3UOAamDgVR411T3YHleDTgLuz90XSO3NFZm1AnaJiJamVRcNGD2zmi4qWkcjKF3E4JKgn1DiCeC3eSb5WELsw8XqRzlvJqG
// 10
// Myanmar Kyat

faker.SetSeed(622)

// Define a new builder
colorBuilder := func(params ...string) (interface{}, error) {
  return faker.Pick("Red", "Yellow", "Blue", "Black", "White"), nil
}

// Register a new builder named "color" for string type
err := faker.RegisterBuilder("color", "string", colorBuilder)
if err != nil {
  panic(err)
}

type Animal struct {
  Name  string `faker:"username"`
  Color string `faker:"color"` // Use custom color builder
}

type Person struct {
  FirstName string            `faker:"firstName"`         // Any available function case insensitive
  LastName  *string           `faker:"lastName"`          // Pointer are also supported
  Age       int               `faker:"intinrange(0,120)"` // Can call with parameters
  UUID      string            `faker:"uuid;unique"`       // Guarantees a unique value
  Number    int               `faker:"-"`                 // Skip this field
  Code      string            // No tag to use default builder for this field type
  Pet       Animal            // Recursively fill this struct
  Nicknames []string          `faker:"username;len=3"`          // Build an array of size 3 using faker.Username function
  Extra     map[string]string `faker:"stringWithSize(3);len=2"` // map are supported
}

p := Person{}
err = faker.Build(&p)
if err != nil {
  panic(err)
}
fmt.Println(p.FirstName)
fmt.Println(*p.LastName)
fmt.Println(p.Age)
fmt.Println(p.UUID)
fmt.Println(p.Number)
fmt.Println(p.Code)
fmt.Println(p.Pet.Name)
fmt.Println(p.Pet.Color)
fmt.Println(len(p.Nicknames))
fmt.Println(p.Nicknames[0])
fmt.Println(p.Nicknames[1])
fmt.Println(p.Nicknames[2])
fmt.Println(p.Extra)
// Output: Wilber
// Gutkowski
// 25
// ff8d6917-b920-46e6-b1be-dc2d48becfcb
// 0
// z
// honegger
// Red
// 3
// teagan
// polypeptide
// chinfest
// map[70w:3F6 gQS:isq]

faker.SetSeed(623)

type User struct {
    Username string `faker:"username"`
    Email    string `faker:"email"`
    Country  string `faker:"CountryAlpha2"`
}

italianUserFactory := func() *User {
    u := &User{Country: "IT"}
    faker.Build(u)
    return u
}

italianUser := italianUserFactory()
fmt.Println(italianUser)
// Output: &{spicule hoag@ornamented.biz IT}

faker.SetSeed(1802)

// Define a new builder
builder := func(params ...string) (interface{}, error) {
    if len(params) > 0 && params[0] == "melee" {
        return faker.Pick("Barbarian", "Bard", "Fighter", "Monk", "Paladin", "Rogue"), nil
    }
    return faker.Pick("Cleric", "Druid", "Ranger", "Sorcerer", "Warlock", "Wizard"), nil
}

// Register a new builder named "dndClass" for string type
err := faker.RegisterBuilder("dndClass", "string", builder)
if err != nil {
    panic(err)
}

player := &struct {
    Class string `faker:"dndClass(melee)"`
    // other fields ...
}{}

// Build a struct with fake data
faker.Build(&player)

fmt.Println(player.Class)
// Output: Paladin