go cache the data in memory, auto to fetch the data if missing.
- based on via patrickmn/go-cache
- retrieveFunc will be called if the key not in cache
- TTL required
- cache the missing key for 5s, avoid
cache penetration - use singleflight to avoid
cache breakdown - cache in memory, no need to worry about
cache avalanche - support go version 1.11+
$ go get github.com/wklken/cache
package main
import (
"fmt"
"time"
"github.com/wklken/cache"
)
// 1. impl the reterive func
func RetrieveOK(k cache.Key) (interface{}, error) {
arg := k.(cache.StringKey)
fmt.Println("arg: ", arg)
// you can use the arg to fetch data from database or http request
// username, err := GetFromDatabase(arg)
// if err != nil {
// return nil, err
// }
return "ok", nil
}
func main() {
// 2. new a cache
c := cache.NewCache(
"example",
false,
RetrieveOK,
5*time.Minute)
// 4. use it
k := cache.NewStringKey("hello")
data, err := c.Get(k)
fmt.Println("err == nil: ", err == nil)
fmt.Println("data from cache: ", data)
}package main
import (
"fmt"
"time"
"github.com/wklken/cache"
)
// 1. impl the key interface, Key() string
type ExampleKey struct {
Field1 string
Field2 int64
}
func (k ExampleKey) Key() string {
return fmt.Sprintf("%s:%d", k.Field1, k.Field2)
}
// 2. impl the reterive func
func RetrieveExample(inKey cache.Key) (interface{}, error) {
k := inKey.(ExampleKey)
fmt.Println("ExampleKey Field1 and Field2 value:", k.Field1, k.Field2)
// data, err := GetFromDatabase(k.Field1, k.Field2)
// if err != nil {
// return nil, err
// }
return "world", nil
}
func main() {
// 3. new a cache
c := cache.NewCache(
"example",
false,
RetrieveExample,
5*time.Minute)
// 4. use it
k := ExampleKey{
Field1: "hello",
Field2: 42,
}
data, err := c.Get(k)
fmt.Println("err == nil: ", err == nil)
fmt.Println("data from cache: ", data)
dataStr, err := c.GetString(k)
fmt.Println("err == nil: ", err == nil)
fmt.Printf("data type is %T, value is %s\n", dataStr, dataStr)
}MIT