Golang : Generate universally unique identifier(UUID) example

A UUID ( universally unique identifier ) is a 128-bit string value that is used in developing software. An example of UUID string looks like :

69cda7b3-9a67-47ce-beac-16ce1dc177e0

UUID is commonly used in generating MAC addresses for network interface hardware devices, primary keys identifiers in database to ensure uniqueness in a cluster of database servers and also use in binding registration serial number of shareware/licensed software to customer's computers. In some computer games, UUID is generated on the fly as a way identify objects in the virtual world.

Here are two examples of generating UUID in Golang.

To generate UUID with https://github.com/pborman/uuid example :

 package main

 import (
  "fmt"
  "github.com/pborman/uuid"
 )

 func main() {
  uuid := uuid.New()

  fmt.Println(uuid)
 }

Sample output :

69cda7b3-9a67-47ce-beac-16ce1dc177e0

and for time based UUID generation example :

 package main

 import (
  "crypto/rand"
  "fmt"
  "time"
 )

 func main() {
  // generate 32 bits timestamp
  unix32bits := uint32(time.Now().UTC().Unix())

  buff := make([]byte, 12)

  numRead, err := rand.Read(buff)

  if numRead != len(buff) || err != nil {
 panic(err)
  }

  fmt.Printf("%x-%x-%x-%x-%x-%x\n", unix32bits, buff[0:2], buff[2:4], buff[4:6], buff[6:8], buff[8:])
 }

Sample output :

564e9408-fb78-4856-4215-52e0-e14bb054

References :

https://en.wikipedia.org/wiki/Universallyuniqueidentifier

http://www.ietf.org/rfc/rfc4122.txt

https://github.com/pborman/uuid/blob/master/uuid.go