zitadel/internal/id/sonyflake.go

package id

import (
	"errors"
	"net"
	"os"

	"strconv"
	"time"

	"github.com/sony/sonyflake"
)

type sonyflakeGenerator struct {
	*sonyflake.Sonyflake
}

func (s *sonyflakeGenerator) Next() (string, error) {
	id, err := s.NextID()
	if err != nil {
		return "", err
	}
	return strconv.FormatUint(id, 10), nil
}

var (
	SonyFlakeGenerator = Generator(&sonyflakeGenerator{
		sonyflake.NewSonyflake(sonyflake.Settings{
			MachineID: lower16BitPrivateIP,
			StartTime: time.Date(2019, 4, 29, 0, 0, 0, 0, time.UTC),
		}),
	})
)

// the following is a copy of sonyflake (https://github.com/sony/sonyflake/blob/master/sonyflake.go)
//with the change of using the "POD-IP" if no private ip is found
func privateIPv4() (net.IP, error) {
	as, err := net.InterfaceAddrs()
	if err != nil {
		return nil, err
	}

	for _, a := range as {
		ipnet, ok := a.(*net.IPNet)
		if !ok || ipnet.IP.IsLoopback() {
			continue
		}

		ip := ipnet.IP.To4()
		if isPrivateIPv4(ip) {
			return ip, nil
		}
	}

	//change: use "POD_IP"
	ip := net.ParseIP(os.Getenv("POD_IP"))
	if ip == nil {
		return nil, errors.New("no private ip address")
	}
	if ipV4 := ip.To4(); ipV4 != nil {
		return ipV4, nil
	}
	return nil, errors.New("no pod ipv4 address")
}

func isPrivateIPv4(ip net.IP) bool {
	return ip != nil &&
		(ip[0] == 10 || ip[0] == 172 && (ip[1] >= 16 && ip[1] < 32) || ip[0] == 192 && ip[1] == 168)
}

func lower16BitPrivateIP() (uint16, error) {
	ip, err := privateIPv4()
	if err != nil {
		return 0, err
	}

	return uint16(ip[2])<<8 + uint16(ip[3]), nil
}