缓存支持读取缓存key的剩余有效时间

gocache.go

@@ -32,6 +32,24 @@ func (g *Gocache) Exist(ctx context.Context, cacheInstanceFlag string, key strin
 	return exist, nil
 }
 
+func (g *Gocache) TTL(ctx context.Context, cacheInstanceFlag string, key string) (int64, error) {
+	var (
+		exist    bool
+		expireAt time.Time
+	)
+
+	_, expireAt, exist = GocacheStorageClient.Get(cacheInstanceFlag).GetWithExpiration(key)
+	if !exist {
+		// 和redis key不存在返回值一致
+		return -2, nil
+	}
+	if expireAt.Unix() == 0 {
+		// 存在并且未设置过期时间, 和redis key返回值一致
+		return -1, nil
+	}
+	return expireAt.Unix() - time.Now().Unix(), nil
+}
+
 func (g *Gocache) Set(ctx context.Context, cacheInstanceFlag string, key string, value string, ttl int64) error {
 	now := time.Now()
 	if now.Unix() < ttl {