Simple Golang file cache

FileCache.go

package utilities

import (
	"path/filepath"
	"os"
	"sync"
	"io/ioutil"
	"time"
	"github.com/vmihailenco/msgpack"
)

type fileCache struct {
	fileMu sync.RWMutex
	path   string
	ttl    time.Duration
}

var fCache *fileCache

func FileCache() *fileCache {
	if fCache == nil {
		path, err := filepath.Abs(filepath.Dir(os.Args[0]))
		if err != nil {
			panic(err)
		}
		path += "/tmp"
		fCache = NewFileCache(path, 24*time.Hour)
	}
	return fCache
}

func NewFileCache(path string, ttl time.Duration) *fileCache {
	os.MkdirAll(path, os.ModePerm)
	return &fileCache{
		path: path,
		ttl:  ttl,
	}
}

func (c *fileCache) Load(fileName string, f interface{}) error {

	filePath := c.path + "/" + fileName

	fileInfo, _ := os.Stat(filePath)
	if fileInfo == nil || fileInfo.ModTime().Add(c.ttl).Before(time.Now()) {
		return nil
	}

	data, err := ioutil.ReadFile(filePath)
	if err != nil {
		return err
	}

	return msgpack.Unmarshal(data, f)
}

func (c *fileCache) Save(f interface{}, fileName string) error {
	c.fileMu.Lock()
	defer c.fileMu.Unlock()
	data, err := msgpack.Marshal(f)
	if err != nil {
		return err
	}
	return ioutil.WriteFile(c.path+"/"+fileName, data, 0666)
}