调用
var snowNode *snowflake.Node
if snowNode == nil {
node, err := snowflake.NewNode(0)
if err != nil {
panic(err)
}
snowNode = node
}
fmt.Sprintf("%s%d", prefix, snowNode.Generate())
实现
// Package snowflake provides a very simple Twitter snowflake generator and parser.
package snowflake
import (
"encoding/base64"
"encoding/binary"
"errors"
"fmt"
"gitlab.bianjie.ai/avata/orders/order-server/internal/pkg/configs"
"strconv"
"sync"
"time"
)
var (
// Epoch is set to the twitter snowflake epoch of Nov 04 2010 01:42:54 UTC in milliseconds
// You may customize this to set a different epoch for your application.
Epoch int64 = 1288834974657
// NodeBits holds the number of bits to use for Node
// Remember, you have a total 22 bits to share between Node/Step
NodeBits uint8 = 10
// StepBits holds the number of bits to use for Step
// Remember, you have a total 22 bits to share between Node/Step
StepBits uint8 = 12
// DEPRECATED: the below four variables will be removed in a future release.
mu sync.Mutex
nodeMax int64 = -1 ^ (-1 << NodeBits)
nodeMask = nodeMax << StepBits
stepMask int64 = -1 ^ (-1 << StepBits)
timeShift = NodeBits + StepBits
nodeShift = StepBits
SnakeNode *Node
)
const encodeBase32Map = "ybndrfg8ejkmcpqxot1uwisza345h769"
var decodeBase32Map [256]byte
const encodeBase58Map = "123456789abcdefghijkmnopqrstuvwxyzABCDEFGHJKLMNPQRSTUVWXYZ"
var decodeBase58Map [256]byte
// A JSONSyntaxError is returned from UnmarshalJSON if an invalid ID is provided.
type JSONSyntaxError struct{ original []byte }
func (j JSONSyntaxError) Error() string {
return fmt.Sprintf("invalid snowflake ID %q", string(j.original))
}
// ErrInvalidBase58 is returned by ParseBase58 when given an invalid []byte
var ErrInvalidBase58 = errors.New("invalid base58")
// ErrInvalidBase32 is returned by ParseBase32 when given an invalid []byte
var ErrInvalidBase32 = errors.New("invalid base32")
// Create maps for decoding Base58/Base32.
// This speeds up the process tremendously.
func init() {
for i := 0; i < len(decodeBase58Map); i++ {
decodeBase58Map[i] = 0xFF
}
for i := 0; i < len(encodeBase58Map); i++ {
decodeBase58Map[encodeBase58Map[i]] = byte(i)
}
for i := 0; i < len(decodeBase32Map); i++ {
decodeBase32Map[i] = 0xFF
}
for i := 0; i < len(encodeBase32Map); i++ {
decodeBase32Map[encodeBase32Map[i]] = byte(i)
}
}
// A Node struct holds the basic information needed for a snowflake generator
// node
type Node struct {
mu sync.Mutex
epoch time.Time
time int64
node int64
step int64
nodeMax int64
nodeMask int64
stepMask int64
timeShift uint8
nodeShift uint8
}
// An ID is a custom type used for a snowflake ID. This is used so we can
// attach methods onto the ID.
type ID int64
// NewNode returns a new snowflake node that can be used to generate snowflake
// IDs
func NewNode(node int64) (*Node, error) {
configs.GlobalContext.Logger.WithField("snow_node_index", node).Info("init snow node index")
// re-calc in case custom NodeBits or StepBits were set
// DEPRECATED: the below block will be removed in a future release.
mu.Lock()
nodeMax = -1 ^ (-1 << NodeBits)
nodeMask = nodeMax << StepBits
stepMask = -1 ^ (-1 << StepBits)
timeShift = NodeBits + StepBits
nodeShift = StepBits
mu.Unlock()
n := Node{}
n.node = node
n.nodeMax = -1 ^ (-1 << NodeBits)
n.nodeMask = n.nodeMax << StepBits
n.stepMask = -1 ^ (-1 << StepBits)
n.timeShift = NodeBits + StepBits
n.nodeShift = StepBits
if n.node < 0 || n.node > n.nodeMax {
return nil, errors.New("Node number must be between 0 and " + strconv.FormatInt(n.nodeMax, 10))
}
var curTime = time.Now()
// add time.Duration to curTime to make sure we use the monotonic clock if available
n.epoch = curTime.Add(time.Unix(Epoch/1000, (Epoch%1000)*1000000).Sub(curTime))
SnakeNode = &n
return &n, nil
}
// Generate creates and returns a unique snowflake ID
// To help guarantee uniqueness
// - Make sure your system is keeping accurate system time
// - Make sure you never have multiple nodes running with the same node ID
func (n *Node) Generate() ID {
n.mu.Lock()
now := time.Since(n.epoch).Nanoseconds() / 1000000
if now == n.time {
n.step = (n.step + 1) & n.stepMask
if n.step == 0 {
for now <= n.time {
now = time.Since(n.epoch).Nanoseconds() / 1000000
}
}
} else {
n.step = 0
}
n.time = now
r := ID((now)<<n.timeShift |
(n.node << n.nodeShift) |
(n.step),
)
n.mu.Unlock()
return r
}
// Int64 returns an int64 of the snowflake ID
func (f ID) Int64() int64 {
return int64(f)
}
// ParseInt64 converts an int64 into a snowflake ID
func ParseInt64(id int64) ID {
return ID(id)
}
// String returns a string of the snowflake ID
func (f ID) String() string {
return strconv.FormatInt(int64(f), 10)
}
// ParseString converts a string into a snowflake ID
func ParseString(id string) (ID, error) {
i, err := strconv.ParseInt(id, 10, 64)
return ID(i), err
}
// Base2 returns a string base2 of the snowflake ID
func (f ID) Base2() string {
return strconv.FormatInt(int64(f), 2)
}
// ParseBase2 converts a Base2 string into a snowflake ID
func ParseBase2(id string) (ID, error) {
i, err := strconv.ParseInt(id, 2, 64)
return ID(i), err
}
// Base32 uses the z-base-32 character set but encodes and decodes similar
// to base58, allowing it to create an even smaller result string.
// NOTE: There are many different base32 implementations so becareful when
// doing any interoperation.
func (f ID) Base32() string {
if f < 32 {
return string(encodeBase32Map[f])
}
b := make([]byte, 0, 12)
for f >= 32 {
b = append(b, encodeBase32Map[f%32])
f /= 32
}
b = append(b, encodeBase32Map[f])
for x, y := 0, len(b)-1; x < y; x, y = x+1, y-1 {
b[x], b[y] = b[y], b[x]
}
return string(b)
}
// ParseBase32 parses a base32 []byte into a snowflake ID
// NOTE: There are many different base32 implementations so becareful when
// doing any interoperation.
func ParseBase32(b []byte) (ID, error) {
var id int64
for i := range b {
if decodeBase32Map[b[i]] == 0xFF {
return -1, ErrInvalidBase32
}
id = id*32 + int64(decodeBase32Map[b[i]])
}
return ID(id), nil
}
// Base36 returns a base36 string of the snowflake ID
func (f ID) Base36() string {
return strconv.FormatInt(int64(f), 36)
}
// ParseBase36 converts a Base36 string into a snowflake ID
func ParseBase36(id string) (ID, error) {
i, err := strconv.ParseInt(id, 36, 64)
return ID(i), err
}
// Base58 returns a base58 string of the snowflake ID
func (f ID) Base58() string {
if f < 58 {
return string(encodeBase58Map[f])
}
b := make([]byte, 0, 11)
for f >= 58 {
b = append(b, encodeBase58Map[f%58])
f /= 58
}
b = append(b, encodeBase58Map[f])
for x, y := 0, len(b)-1; x < y; x, y = x+1, y-1 {
b[x], b[y] = b[y], b[x]
}
return string(b)
}
// ParseBase58 parses a base58 []byte into a snowflake ID
func ParseBase58(b []byte) (ID, error) {
var id int64
for i := range b {
if decodeBase58Map[b[i]] == 0xFF {
return -1, ErrInvalidBase58
}
id = id*58 + int64(decodeBase58Map[b[i]])
}
return ID(id), nil
}
// Base64 returns a base64 string of the snowflake ID
func (f ID) Base64() string {
return base64.StdEncoding.EncodeToString(f.Bytes())
}
// ParseBase64 converts a base64 string into a snowflake ID
func ParseBase64(id string) (ID, error) {
b, err := base64.StdEncoding.DecodeString(id)
if err != nil {
return -1, err
}
return ParseBytes(b)
}
// Bytes returns a byte slice of the snowflake ID
func (f ID) Bytes() []byte {
return []byte(f.String())
}
// ParseBytes converts a byte slice into a snowflake ID
func ParseBytes(id []byte) (ID, error) {
i, err := strconv.ParseInt(string(id), 10, 64)
return ID(i), err
}
// IntBytes returns an array of bytes of the snowflake ID, encoded as a
// big endian integer.
func (f ID) IntBytes() [8]byte {
var b [8]byte
binary.BigEndian.PutUint64(b[:], uint64(f))
return b
}
// ParseIntBytes converts an array of bytes encoded as big endian integer as
// a snowflake ID
func ParseIntBytes(id [8]byte) ID {
return ID(int64(binary.BigEndian.Uint64(id[:])))
}
// Time returns an int64 unix timestamp in milliseconds of the snowflake ID time
// DEPRECATED: the below function will be removed in a future release.
func (f ID) Time() int64 {
return (int64(f) >> timeShift) + Epoch
}
// Node returns an int64 of the snowflake ID node number
// DEPRECATED: the below function will be removed in a future release.
func (f ID) Node() int64 {
return int64(f) & nodeMask >> nodeShift
}
// Step returns an int64 of the snowflake step (or sequence) number
// DEPRECATED: the below function will be removed in a future release.
func (f ID) Step() int64 {
return int64(f) & stepMask
}
// MarshalJSON returns a json byte array string of the snowflake ID.
func (f ID) MarshalJSON() ([]byte, error) {
buff := make([]byte, 0, 22)
buff = append(buff, '"')
buff = strconv.AppendInt(buff, int64(f), 10)
buff = append(buff, '"')
return buff, nil
}
// UnmarshalJSON converts a json byte array of a snowflake ID into an ID type.
func (f *ID) UnmarshalJSON(b []byte) error {
if len(b) < 3 || b[0] != '"' || b[len(b)-1] != '"' {
return JSONSyntaxError{b}
}
i, err := strconv.ParseInt(string(b[1:len(b)-1]), 10, 64)
if err != nil {
return err
}
*f = ID(i)
return nil
}
