179 lines
3.8 KiB
Go
179 lines
3.8 KiB
Go
package services
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import (
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"context"
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"errors"
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"fmt"
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"platform/pkg/rds"
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"strings"
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"time"
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"github.com/google/uuid"
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"github.com/jxskiss/base62"
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"github.com/redis/go-redis/v9"
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)
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var ID IdService = IdService{}
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type IdService struct {
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}
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// region SerialID
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const (
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// 保留位，确保最高位为0，防止产生负值
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reservedBits = 1
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// 时间戳位数
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timestampBits = 41
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// 序列号位数
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sequenceBits = 22
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// 最大序列号掩码：2^22 - 1
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maxSequence = (1 << sequenceBits) - 1
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// 位移计算常量
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timestampShift = sequenceBits
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// Redis 缓存过期时间（秒）
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redisTTL = 5
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)
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var (
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ErrSequenceOverflow = errors.New("sequence overflow")
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)
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func (s *IdService) GenSerial(ctx context.Context) (uint64, error) {
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// 构造Redis键
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now := time.Now().Unix()
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key := idSerialKey(now)
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// 使用Redis事务确保原子操作
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var sequence int64
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err := rds.Client.Watch(ctx, func(tx *redis.Tx) error {
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// 获取当前序列号
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currentVal, err := tx.Get(ctx, key).Int64()
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if err != nil && !errors.Is(err, redis.Nil) {
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return err
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}
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if errors.Is(err, redis.Nil) {
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currentVal = 0
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}
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sequence = currentVal + 1
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// 检查序列号是否溢出
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if sequence > maxSequence {
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return ErrSequenceOverflow
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}
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// 将更新后的序列号保存回Redis，设置5秒过期时间
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pipe := tx.Pipeline()
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pipe.Set(ctx, key, sequence, redisTTL*time.Second)
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_, err = pipe.Exec(ctx)
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return err
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}, key)
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if err != nil {
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return 0, err
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}
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// 组装最终ID
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id := uint64((now << timestampShift) | sequence)
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return id, nil
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}
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// ParseSerial 解析ID，返回其组成部分
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func (s *IdService) ParseSerial(id uint64) (timestamp int64, sequence int64) {
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// 通过位运算和掩码提取各部分
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timestamp = int64(id >> timestampShift)
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sequence = int64(id & maxSequence)
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return
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}
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// idSerialKey 根据时间戳生成Redis键
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func idSerialKey(timestamp int64) string {
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return fmt.Sprintf("global:id:serial:%d", timestamp)
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}
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// endregion
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// region ReadableID
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// GenReadable 根据给定的标签生成易读的全局唯一标识符
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// tag 参数用于标识 ID 的用途，如 "usr" 表示用户ID，"ord" 表示订单ID等
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// 生成的 ID 格式为：<tag>_<encoded-uuid>，例如：usr_7NLmVLeHwqS73enFZ1i8tB
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func (s *IdService) GenReadable(tag string) string {
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// 生成 UUID
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id := uuid.New()
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// 将 UUID 编码为 Base62 字符串（更短，更易读）
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encoded := base62.EncodeToString(id[:])
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// 如标签为空，则直接返回编码后的字符串
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if tag == "" {
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return encoded
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}
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// 标准化标签：转换为小写并移除特殊字符
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tag = normalizeTag(tag)
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// 组合最终 ID
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return fmt.Sprintf("%s_%s", tag, encoded)
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}
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// ParseReadableID 解析易读ID，返回其标签和编码部分
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func (s *IdService) ParseReadableID(id string) (tag string, encoded string) {
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parts := strings.SplitN(id, "_", 2)
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if len(parts) != 2 {
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return "", id
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}
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return parts[0], parts[1]
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}
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// TryDecodeID 尝试将编码部分解码回 UUID
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// 如果解码失败，返回错误
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func (s *IdService) TryDecodeID(encoded string) (uuid.UUID, error) {
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// 尝试解码 Base62 编码
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bytes, err := base62.DecodeString(encoded)
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if err != nil {
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return uuid.UUID{}, err
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}
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// 确保长度正确
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if len(bytes) != 16 {
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return uuid.UUID{}, fmt.Errorf("invalid UUID length after decoding: %d", len(bytes))
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}
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// 转换为 UUID
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var result uuid.UUID
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copy(result[:], bytes)
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return result, nil
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}
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// normalizeTag 标准化标签
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// 转换为小写，移除特殊字符，最多保留 5 个字符
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func normalizeTag(tag string) string {
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// 转换为小写
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tag = strings.ToLower(tag)
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// 移除特殊字符
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var sb strings.Builder
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for _, c := range tag {
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if (c >= 'a' && c <= 'z') || (c >= '0' && c <= '9') {
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sb.WriteRune(c)
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}
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}
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// 截取最多 5 个字符
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result := sb.String()
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if len(result) > 5 {
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result = result[:5]
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}
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return result
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}
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// endregion
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