idgen

Documentation

Index

• Constants
• Variables
• type Counter
• type CounterStore
  • func NewMongoDBCounter(uri, db, label string) CounterStore
  • func NewRedisCounter(addr, key string) CounterStore
• type IDGenerator
• type MongoDBCounter
  • func (s *MongoDBCounter) Close() error
  • func (s *MongoDBCounter) Incr(ctx context.Context) (int64, error)
  • func (s *MongoDBCounter) IncrementAndLoad(ctx context.Context, n int, ctr *Counter) error
  • func (s *MongoDBCounter) Init(ctx context.Context) error
• type RedisCounter
  • func (s *RedisCounter) Close() error
  • func (s *RedisCounter) Incr(ctx context.Context) (int64, error)
  • func (s *RedisCounter) Init(ctx context.Context) error
• type SegmentIDGen
  • func NewSegmentIDGen(store CounterStore, step int32) *SegmentIDGen
  • func (g *SegmentIDGen) Init(ctx context.Context) error
  • func (g *SegmentIDGen) MustNext(ctx context.Context) int64
  • func (g *SegmentIDGen) Next(ctx context.Context) (int64, error)
• type Snowflake
  • func NewSnowflake(workerId uint16) *Snowflake
  • func (sf *Snowflake) MustNext() int64
  • func (sf *Snowflake) Next() (int64, error)
• type StorageType

Constants

const (
	SequenceBits       = 12
	WorkerIDBits       = 13
	TimeUnitBits       = 36
	ClockBackwardsBits = 2
	WorkIDMask         = 1<<WorkerIDBits - 1
	MaxSeqID           = (1 << SequenceBits) - 1
	TimestampShift     = WorkerIDBits + SequenceBits
	MaxTimeUnits       = (1 << TimeUnitBits) - 1
	BackwardsMaskShift = TimeUnitBits + WorkerIDBits + SequenceBits

	TimeUnit    = int64(time.Millisecond * 10)    // 厘秒（10毫秒）
	CustomEpoch = int64(1704038400 * time.Second) // 起始纪元 2024-01-01 00:00:00 UTC
)

一个64位UUID由以下部分组成

1位符号位
2位时钟回拨标记，时钟最多被回拨3次
36位时间戳（厘秒），~=21y288d, 最大可以表示到2045-10-10
13位服务器ID，最大服务器ID=8191
12位序列号，单个时间单位的最大分配数量（4096/毫秒）

const (
	CollectionName = "uuid"
)

const (
	DefaultSeqIDStep = 2000 // 默认步长
)

Variables

var (
	ErrClockGoneBackwards = errors.New("clock gone backwards")
	ErrTimeUnitOverflow   = errors.New("clock time unit overflow")
	ErrUUIDIntOverflow    = errors.New("uuid integer overflow")
)

var ErrCounterOutOfRange = errors.New("counter out of range")

Types

type Counter

type Counter struct {
	Label string `bson:"label"`   // 识别符
	Value int64  `bson:"counter"` // 计数器
}

Counter 计数器

type CounterStore

type CounterStore interface {
	Init(context.Context) error
	Close() error
	Incr(context.Context) (int64, error)
}

CounterStore 表示一个存储组件，维持一个持续递增（不一定连续）的counter

func NewMongoDBCounter

func NewMongoDBCounter(uri, db, label string) CounterStore

func NewRedisCounter

func NewRedisCounter(addr, key string) CounterStore

type IDGenerator

type IDGenerator interface {
	Next(context.Context) (int64, error)
}

IDGenerator ID生成器

type MongoDBCounter

type MongoDBCounter struct {
	// contains filtered or unexported fields
}

MongoDBCounter 使用MongoDB的自增计数器

func (*MongoDBCounter) Close

func (s *MongoDBCounter) Close() error

func (*MongoDBCounter) Incr

func (s *MongoDBCounter) Incr(ctx context.Context) (int64, error)

func (*MongoDBCounter) IncrementAndLoad

func (s *MongoDBCounter) IncrementAndLoad(ctx context.Context, n int, ctr *Counter) error

IncrementAndLoad 把counter自增再读取最新的counter https://docs.mongodb.com/manual/core/write-operations-atomicity/

func (*MongoDBCounter) Init

func (s *MongoDBCounter) Init(ctx context.Context) error

type RedisCounter

type RedisCounter struct {
	// contains filtered or unexported fields
}

RedisCounter 基于redis INCR命令实现的计数器

func (*RedisCounter) Close

func (s *RedisCounter) Close() error

func (*RedisCounter) Incr

func (s *RedisCounter) Incr(ctx context.Context) (int64, error)

func (*RedisCounter) Init

func (s *RedisCounter) Init(ctx context.Context) error

type SegmentIDGen

type SegmentIDGen struct {
	// contains filtered or unexported fields
}

func NewSegmentIDGen

func NewSegmentIDGen(store CounterStore, step int32) *SegmentIDGen

func (*SegmentIDGen) Init

func (g *SegmentIDGen) Init(ctx context.Context) error

func (*SegmentIDGen) MustNext

func (g *SegmentIDGen) MustNext(ctx context.Context) int64

func (*SegmentIDGen) Next

func (g *SegmentIDGen) Next(ctx context.Context) (int64, error)

Next 分配下一个ID

type Snowflake

type Snowflake struct {
	// contains filtered or unexported fields
}

func NewSnowflake

func NewSnowflake(workerId uint16) *Snowflake

func (*Snowflake) MustNext

func (sf *Snowflake) MustNext() int64

func (*Snowflake) Next

func (sf *Snowflake) Next() (int64, error)

type StorageType

type StorageType int8

const (
	StorageMongoDB StorageType = 1
	StorageRedis   StorageType = 2
)