go语言生成uuid

操作系统： CentOS 6.9_x64

go语言版本： 1.8.3

问题描述

golang没有提供生成uuid的接口，但开发中确实需要uuid。

这里把看到的代码记录下，也方便我以后查阅。

解决方案

示例代码如下：

package main

import (
    "fmt"
    "sync/atomic"
    "time"
)

type UUID [16]byte

var timeBase = time.Date(1582, time.October, 15, 0, 0, 0, 0, time.UTC).Unix()
var hardwareAddr []byte
var clockSeq uint32

func TimeUUID() UUID {
    return FromTime(time.Now())
}

func FromTime(aTime time.Time) UUID {
    var u UUID

    utcTime := aTime.In(time.UTC)
    t := uint64(utcTime.Unix()-timeBase)*10000000 + uint64(utcTime.Nanosecond()/100)
    u[0], u[1], u[2], u[3] = byte(t>>24), byte(t>>16), byte(t>>8), byte(t)
    u[4], u[5] = byte(t>>40), byte(t>>32)
    u[6], u[7] = byte(t>>56)&0x0F, byte(t>>48)

    clock := atomic.AddUint32(&clockSeq, 1)
    u[8] = byte(clock >> 8)
    u[9] = byte(clock)

    copy(u[10:], hardwareAddr)

    u[6] |= 0x10 // set version to 1 (time based uuid)
    u[8] &= 0x3F // clear variant
    u[8] |= 0x80 // set to IETF variant

    return u
}

func (u UUID) String() string {
    var offsets = [...]int{0, 2, 4, 6, 9, 11, 14, 16, 19, 21, 24, 26, 28, 30, 32, 34}
    const hexString = "0123456789abcdef"
    r := make([]byte, 36)
    for i, b := range u {
        r[offsets[i]] = hexString[b>>4]
        r[offsets[i]+1] = hexString[b&0xF]
    }
    r[8] = '-'
    r[13] = '-'
    r[18] = '-'
    r[23] = '-'
    return string(r)
}

func main() {
    out := TimeUUID()
    fmt.Printf("%s\n", out.String())
}

运行效果：

[root@local t2]# go run uuidTest.go
[root@local t2]#
3e42d638-5243-11e7-8001-000000000000

讨论

当然如果你只是想快速的得到uuid，而且使用的是linux系统，可以直接使用uuidgen命令来获取。

示例代码如下：

package main

import (
    "fmt"
    "log"
    "os/exec"
)

//run in linux
func main() {
    out, err := exec.Command("uuidgen").Output()
    if err != nil {
        log.Fatal(err)
    }
    fmt.Printf("%s", out)
}