我正在尝试使用 Go 作为教程构建一个基本的缓存系统。
出于某种原因,当我运行它时,if else 语句会导致错误。
package datasource
import (
"fmt"
"github.com/patrickmn/go-cache"
"time"
)
type DataSource interface {
Value(key string) (interface{}, error)
}
// DataSourceStr type, implements the DataSource interface
type DataSourceStr struct {
data map[string]string
}
var cache = cache.New(5*time.Minute, 5*time.Minute)
func (n *DataSourceStr) Value(key string) (interface{}, error) {
/*
1. Compute a cache key
2. Search cache key
3. If hit return value
4. If miss, do datasource
5. Cache and return slow thing.
*/
cached, found := cache.Value(key)
if found {
return cached, nil
}
else if _, ok := n.data[key]; ok
{
//measure how often a key gets called.
cache.Set(key, n.data[key], cache.DefaultExpiration)
return n.data[key], nil
} else {
return nil, fmt.Errorf("key not found %v", ok)
}
}
func getFromDS(datasource DataSource, key string) (string, error) {
v, err := datasource.Value(key)
//create a map that decays based on time.
if err != nil {
return "", nil
}
return fmt.Sprint(v), nil
}
我做错了什么?我正在尝试输入一个键,然后从缓存或数据库中返回该值。不确定我在语法上做错了什么!