57 lines
1.3 KiB
Go
57 lines
1.3 KiB
Go
package logic
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import (
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"context"
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"encoding/json"
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"time"
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"bj_power_mes/internal/svc"
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)
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// Service 业务逻辑服务（handler 薄层调用）
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type Service struct {
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ctx *svc.ServiceContext
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}
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func New(s *svc.ServiceContext) *Service {
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return &Service{ctx: s}
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}
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// cached 看板缓存：TTL + 防击穿（SETNX 锁），同一 key 同时仅一个打到 DB
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func (s *Service) cached(ctx context.Context, key string, ttl int, build func() (any, error)) (any, error) {
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if s.ctx.RedisClient == nil {
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return build()
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}
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if v, err := s.ctx.RedisClient.Get(key); err == nil && v != "" {
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var out any
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if json.Unmarshal([]byte(v), &out) == nil {
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return out, nil
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}
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}
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lockKey := key + ":lock"
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ok, _ := s.ctx.RedisClient.SetnxEx(lockKey, "1", 10)
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if !ok {
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// 有人正在重建缓存：短暂等待后重读
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for i := 0; i < 10; i++ {
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time.Sleep(100 * time.Millisecond)
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if v, err := s.ctx.RedisClient.Get(key); err == nil && v != "" {
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var out any
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if json.Unmarshal([]byte(v), &out) == nil {
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return out, nil
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}
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}
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}
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return build()
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}
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defer func() { _, _ = s.ctx.RedisClient.Del(lockKey) }()
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data, err := build()
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if err == nil {
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if b, e := json.Marshal(data); e == nil {
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_ = s.ctx.RedisClient.Setex(key, string(b), ttl)
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}
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}
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return data, err
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}
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