能指定缓存时间的上下偏差

cache.go

@@ -16,7 +16,8 @@ type QueryFunc[T any] func() (T, error)
 func QueryWithCache[T any](rdb redis.UniversalClient, key string, model *T, query QueryFunc[*T], options ...Option) (bool, error) {
 	// 获取缓存配置
 	config := CacheConfig{
-		cacheTime: getDefaultCacheTime(),
+		cacheTime: DefaultCacheTime,
+		diff:      DefaultCacheTimeDiff,
 		ctx:       context.Background(),
 		flush:     false,
 		write:     true,
@@ -36,7 +37,7 @@ func QueryWithCache[T any](rdb redis.UniversalClient, key string, model *T, quer
 
 		// 刷新缓存时间
 		if config.flush {
-			return true, rdb.Expire(config.ctx, key, config.cacheTime).Err()
+			return true, rdb.Expire(config.ctx, key, computeCacheTime(config.cacheTime, config.diff)).Err()
 		}
 		return true, nil
 	} else if errors.Is(err, redis.Nil) {
@@ -66,5 +67,5 @@ func cacheMiss[T any](rdb redis.UniversalClient, key string, model *T, query Que
 		return err
 	}
 
-	return rdb.SetEx(config.ctx, key, string(data), config.cacheTime).Err()
+	return rdb.SetEx(config.ctx, key, string(data), computeCacheTime(config.cacheTime, config.diff)).Err()
 }

option.go

@@ -15,26 +15,33 @@ var (
 
 type CacheConfig struct {
 	cacheTime time.Duration
+	diff      time.Duration
 	ctx       context.Context
 	flush     bool
 	write     bool
 }
 
-// 获取默认缓存时间，默认为 [25, 35) min
-func getDefaultCacheTime() time.Duration {
-	diff := time.Duration(rand.Int63()%int64(2*DefaultCacheTimeDiff)) - DefaultCacheTimeDiff
-	return max(0, DefaultCacheTime+diff)
+// 计算缓存时间，默认为 [25, 35) min
+func computeCacheTime(cacheTime time.Duration, diff time.Duration) time.Duration {
+	return max(0, cacheTime+time.Duration(rand.Int63()%int64(2*diff))-diff)
 }
 
 type Option func(c *CacheConfig)
 
-// WithCacheTime 指定缓存时间，默认为 [25, 35) min
+// WithCacheTime 指定缓存时间，默认为 30 min
 func WithCacheTime(cacheTime time.Duration) Option {
 	return func(c *CacheConfig) {
 		c.cacheTime = cacheTime
 	}
 }
 
+// WithCacheTimeDiff 指定缓存时间上下偏差，默认为 5 min
+func WithCacheTimeDiff(diff time.Duration) Option {
+	return func(c *CacheConfig) {
+		c.diff = diff
+	}
+}
+
 // WithContext 指定使用redis时的context，默认为background
 func WithContext(ctx context.Context) Option {
 	return func(c *CacheConfig) {