Agfdhyk

You can generate UUIDs using the go-uuid library. This can be installed with:

go get github.com/nu7hatch/gouuid

You can generate random (version 4) UUIDs with:

import "github.com/nu7hatch/gouuid"



...



u, err := uuid.NewV4()

The returned UUID type is a 16 byte array, so you can retrieve the binary value easily. It also provides the standard hex string representation via its String() method.

The code you have also looks like it will also generate a valid version 4 UUID: the bitwise manipulation you perform at the end set the version and variant fields of the UUID to correctly identify it as version 4. This is done to distinguish random UUIDs from ones generated via other algorithms (e.g. version 1 UUIDs based on your MAC address and time).

The go-uuid library is NOT RFC4122 compliant. The variant bits are not set correctly. There have been several attempts by community members to have this fixed but pull requests for the fix are not being accepted.

You can generate UUIDs using the Go uuid library I rewrote based on the go-uuid library. There are several fixes and improvements. This can be installed with:

go get github.com/twinj/uuid

You can generate random (version 4) UUIDs with:

import "github.com/twinj/uuid"



u := uuid.NewV4()

The returned UUID type is an interface and the underlying type is an array.

The library also generates v1 UUIDs and correctly generates v3 and 5 UUIDs. There are several new methods to help with printing and formatting and also new general methods to create UUIDs based off of existing data.

"crypto/rand" is cross platform pkg for random bytes generattion

package main



import (

    "crypto/rand"

    "fmt"

)



func pseudo_uuid() (uuid string) {



    b := make(byte, 16)

    _, err := rand.Read(b)

    if err != nil {

        fmt.Println("Error: ", err)

        return

    }



    uuid = fmt.Sprintf("%X-%X-%X-%X-%X", b[0:4], b[4:6], b[6:8], b[8:10], b[10:])



    return

}

gofrs/uuid is the replacement for satori/go.uuid, which is the most starred UUID package for Go. It supports UUID versions 1-5 and is RFC 4122 and DCE 1.1 compliant.

import "github.com/gofrs/uuid"



// Create a Version 4 UUID, panicking on error

u := uuid.Must(uuid.NewV4())

From Russ Cox's post:

There's no official library. Ignoring error checking,
this seems like it would work fine:

f, _ := os.Open("/dev/urandom")

b := make(byte, 16)

f.Read(b)

f.Close()

uuid := fmt.Sprintf("%x-%x-%x-%x-%x", b[0:4], b[4:6], b[6:8], b[8:10], b[10:])

Note: In the original, pre Go 1 version the first line was:

f, _ := os.Open("/dev/urandom", os.O_RDONLY, 0)

Here it compiles and executes, only /dev/urandom returns all zeros in the playground. Should work fine locally.

In the same thread there are some other methods/references/packages found.

As part of the uuid spec, if you generate a uuid from random it must contain a "4" as the 13th character and a "8", "9", "a", or "b" in the 17th (source).

// this makes sure that the 13th character is "4"

u[6] = (u[6] | 0x40) & 0x4F

// this makes sure that the 17th is "8", "9", "a", or "b"

u[8] = (u[8] | 0x80) & 0xBF 

An official implementation by Google is currently under development but not stable yet: https://github.com/google/uuid

Looks like it's the continuation of https://github.com/pborman/uuid from this answer

Generating a version 4 UUID works like this:
uuid, err := uuid.NewRandom()

Update:
A version 1.0.0 has been released and the note regarding possible instability has been removed.

The gorand package has a UUID method that returns a Version 4 (randomly generated) UUID in its canonical string representation ("xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx") and it's RFC 4122 compliant.

It also uses the crypto/rand package to ensure the most cryptographically secure generation of UUIDs across all platforms supported by Go.

import "github.com/leonelquinteros/gorand"



func main() {

    uuid, err := gorand.UUID()

    if err != nil {

        panic(err.Error())

    }



    println(uuid)

} 

You should use google/uuid https://github.com/google/uuid

package main



import (

    "fmt"

    "github.com/google/uuid"

)



func main() {

    id, err := uuid.NewUUID()

    if err !=nil {

        // handle error

    }

    fmt.Printf(id.String())

}

This package is RFC4122 and DCE 1.1 compliant

On Linux, you can read from /proc/sys/kernel/random/uuid:

package main



import "io/ioutil"

import "fmt"



func main() {

    u, _ := ioutil.ReadFile("/proc/sys/kernel/random/uuid")

    fmt.Println(string(u))

}

No external dependencies!

$ go run uuid.go 

3ee995e3-0c96-4e30-ac1e-f7f04fd03e44

This library is our standard for uuid generation and parsing:

https://github.com/pborman/uuid

For Windows, I did recently this:

// +build windows



package main



import (

    "syscall"

    "unsafe"

)



var (

    modrpcrt4 = syscall.NewLazyDLL("rpcrt4.dll")

    procUuidCreate = modrpcrt4.NewProc("UuidCreate")

)



const (

    RPC_S_OK = 0

)



func NewUuid() (byte, error) {

    var uuid [16]byte

    rc, _, e := syscall.Syscall(procUuidCreate.Addr(), 1,

             uintptr(unsafe.Pointer(&uuid[0])), 0, 0)

    if int(rc) != RPC_S_OK {

        if e != 0 {

            return nil, error(e)

        } else {

            return nil, syscall.EINVAL

        }

    }

    return uuid[:], nil

}