Random fake data and struct generator for Go.
- More than 100 generator functions
- Struct generator
- Unique data generator
- Builtin types support
- Easily customizable
- Zero dependencies
- Recursive infinite loop detector
- Benchmarks (coming soon)
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 KyatPlease refer to the godoc for all available functions and more.
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]One of the nice things about Faker is that it can also be used as a factory library. In fact when we call the faker.Build function if a value is not zero then it is not modified, leaving the original value. This allows you to create factory functions very easily:
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}A builder is a variadic function that will take an arbitrary number of strings as arguments and return an interface or an error. This function (builder) can be used to generate fake data and customize the behaviour of Faker. Here an example:
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: PaladinIf you want to contribute to faker with new generator functions please read this wiki!
Bug reports and pull requests are welcome on GitHub at https://github.com/pioz/faker/issues.
The package is available as open source under the terms of the MIT License.