php snowflake git,全局唯一id生成snowflake算法golang实现

snowflake.go

package snowflake

import (

"fmt"

"time"

"errors"

)

/*

组成：0(1 bit) | timestamp in milli second (41 bit) | machine id (10 bit) | index (12 bit)

每毫秒最多生成4096个id，集群机器最多1024台

*/

type Snowflake struct {

lastTimestamp int64

index int16

machId int16

}

func (s *Snowflake)Init(id int16) error {

if id > 0xff {

return errors.New("illegal machine id")

}

s.machId = id

s.lastTimestamp = time.Now().UnixNano()/1e6

s.index = 0

return nil

}

func (s *Snowflake)GetId() (int64, error) {

curTimestamp := time.Now().UnixNano()/1e6

if (curTimestamp == s.lastTimestamp) {

s.index++

if(s.index>0xfff) {

s.index = 0xfff

return -1,errors.New("out of range")

}

} else {

//fmt.Printf("id/ms:%d -- %dn", s.lastTimestamp, s.index)

s.index = 0

s.lastTimestamp = curTimestamp

}

return int64((0x1ffffffffff & s.lastTimestamp) << 22) + int64(0xff << 10) + int64(0xfff & s.index),nil

}

var UUID Snowflake

单元测试

snowflake_test.go

package snowflake

import (

"github.com/deckarep/golang-set"

"testing"

)

// 生成1亿个ID看有没有重复

func TestSnowFlake( t *testing.T ) {

UUID.Init(1024)

s := mapset.NewSet()

for i:=0;i<1e9;i++ {

id,err := UUID.GetId()

if err!= nil {

t.FailNow()

}

if(s.Add(id) == false) {

t.FailNow()

}

}

}

把代码都放到同一个文件夹下，运行

go test -v snowflake_test.go snowflake.go

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