diff --git a/.travis.yml b/.travis.yml
index 000b437..245be03 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -10,5 +10,5 @@ before_install:
   - go get golang.org/x/tools/cmd/cover
 
 script:
-#  - go test -v -cover
+  #  - go test -v -cover
   - $HOME/gopath/bin/goveralls -v -service=travis-ci
diff --git a/README_cn.md b/README_cn.md
index 2d24625..29ccbb9 100644
--- a/README_cn.md
+++ b/README_cn.md
@@ -15,6 +15,9 @@ Go下通用的缓存使用库，通过包装各种常用的驱动，来提供统
 - memCached powered by `github.com/bradfitz/gomemcache`
 - buntdb powered by `github.com/tidwall/buntdb`
 - boltdb powered by `github.com/etcd-io/bbolt`
+- badger db https://github.com/dgraph-io/badger
+- nutsdb https://github.com/xujiajun/nutsdb
+- goleveldb https://github.com/syndtr/goleveldb
 
 ## GoDoc
 
diff --git a/boltdb/boltdb.go b/boltdb/boltdb.go
index e2b40bd..60d04c9 100644
--- a/boltdb/boltdb.go
+++ b/boltdb/boltdb.go
@@ -4,8 +4,9 @@ package boltdb
 import (
 	"bytes"
 	"encoding/gob"
-	"github.com/etcd-io/bbolt"
 	"time"
+
+	"github.com/etcd-io/bbolt"
 )
 
 // BoltDB definition
diff --git a/buntdb/buntdb.go b/buntdb/buntdb.go
index ce08a16..a803176 100644
--- a/buntdb/buntdb.go
+++ b/buntdb/buntdb.go
@@ -2,9 +2,10 @@
 package buntdb
 
 import (
+	"time"
+
 	"github.com/gookit/cache"
 	"github.com/tidwall/buntdb"
-	"time"
 )
 
 // Memory open a file that does not persist to disk.
@@ -75,7 +76,6 @@ func (c *BuntDB) Get(key string) interface{} {
 	if err != nil {
 		return nil
 	}
-
 	return val
 }
 
diff --git a/cache.go b/cache.go
index 02ed141..5424b0f 100644
--- a/cache.go
+++ b/cache.go
@@ -5,11 +5,14 @@ package cache
 
 import (
 	"encoding/json"
+	"io"
 	"time"
 )
 
 // Cache interface definition
 type Cache interface {
+	io.Closer
+
 	// basic op
 	// Has cache key
 	Has(key string) bool
diff --git a/example_test.go b/example_test.go
index cef9e19..994ed0d 100644
--- a/example_test.go
+++ b/example_test.go
@@ -2,6 +2,7 @@ package cache
 
 import (
 	"fmt"
+
 	"github.com/gookit/cache/redis"
 )
 
diff --git a/file_cache.go b/file_cache.go
index 088b1ed..071950c 100644
--- a/file_cache.go
+++ b/file_cache.go
@@ -86,7 +86,7 @@ func (c *FileCache) Get(key string) interface{} {
 	}
 
 	// has been expired. delete it.
-	c.Del(key)
+	c.lastErr = c.Del(key)
 	return nil
 }
 
@@ -129,7 +129,7 @@ func (c *FileCache) Set(key string, val interface{}, ttl time.Duration) (err err
 
 // Del value by key
 func (c *FileCache) Del(key string) error {
-	c.MemoryCache.Del(key)
+	c.lastErr = c.MemoryCache.Del(key)
 
 	c.lock.RLock()
 	defer c.lock.RUnlock()
@@ -166,7 +166,7 @@ func (c *FileCache) SetMulti(values map[string]interface{}, ttl time.Duration) (
 // DelMulti values by multi key
 func (c *FileCache) DelMulti(keys []string) error {
 	for _, key := range keys {
-		c.Del(key)
+		_= c.Del(key)
 	}
 	return nil
 }
diff --git a/leveldb/leveldb.go b/leveldb/leveldb.go
new file mode 100644
index 0000000..db6708b
--- /dev/null
+++ b/leveldb/leveldb.go
@@ -0,0 +1,47 @@
+// Package leveldb use the https://github.com/syndtr/goleveldb as cache driver
+package leveldb
+
+import "time"
+
+// LevelDB definition
+type LevelDB struct {
+
+}
+
+func (c *LevelDB) Has(key string) bool {
+	panic("implement me")
+}
+
+func (c *LevelDB) Get(key string) interface{} {
+	panic("implement me")
+}
+
+func (c *LevelDB) Set(key string, val interface{}, ttl time.Duration) (err error) {
+	panic("implement me")
+}
+
+func (c *LevelDB) Del(key string) error {
+	panic("implement me")
+}
+
+func (c *LevelDB) GetMulti(keys []string) map[string]interface{} {
+	panic("implement me")
+}
+
+func (c *LevelDB) SetMulti(values map[string]interface{}, ttl time.Duration) (err error) {
+	panic("implement me")
+}
+
+func (c *LevelDB) DelMulti(keys []string) error {
+	panic("implement me")
+}
+
+func (c *LevelDB) Clear() error {
+	panic("implement me")
+}
+
+func (c *LevelDB) Close() error {
+	panic("implement me")
+}
+
+
diff --git a/memcached/memcached.go b/memcached/memcached.go
index 374069f..c29a252 100644
--- a/memcached/memcached.go
+++ b/memcached/memcached.go
@@ -2,9 +2,10 @@
 package memcached
 
 import (
+	"time"
+
 	"github.com/bradfitz/gomemcache/memcache"
 	"github.com/gookit/cache"
-	"time"
 )
 
 // MemCached definition
@@ -124,6 +125,11 @@ func (c *MemCached) Clear() error {
 	return c.client.DeleteAll()
 }
 
+// Close driver
+func (*MemCached) Close() error {
+	return nil
+}
+
 // Client get
 func (c *MemCached) Client() *memcache.Client {
 	return c.client
diff --git a/memory_cache.go b/memory_cache.go
index f45166f..6703591 100644
--- a/memory_cache.go
+++ b/memory_cache.go
@@ -49,7 +49,7 @@ func (c *MemoryCache) Get(key string) interface{} {
 		}
 
 		// has been expired. delete it.
-		c.Del(key)
+		_= c.Del(key)
 	}
 
 	c.lock.RUnlock()
@@ -107,7 +107,7 @@ func (c *MemoryCache) SetMulti(values map[string]interface{}, ttl time.Duration)
 // DelMulti values by multi key
 func (c *MemoryCache) DelMulti(keys []string) error {
 	for _, key := range keys {
-		c.Del(key)
+		_= c.Del(key)
 	}
 	return nil
 }
diff --git a/nutsdb/nutsdb.go b/nutsdb/nutsdb.go
new file mode 100644
index 0000000..2828547
--- /dev/null
+++ b/nutsdb/nutsdb.go
@@ -0,0 +1,47 @@
+// Package nutsdb use the https://github.com/xujiajun/nutsdb as cache driver
+package nutsdb
+
+import "time"
+
+// NutsDB definition
+type NutsDB struct {
+
+}
+
+func (c *NutsDB) Has(key string) bool {
+	panic("implement me")
+}
+
+func (c *NutsDB) Get(key string) interface{} {
+	panic("implement me")
+}
+
+func (c *NutsDB) Set(key string, val interface{}, ttl time.Duration) (err error) {
+	panic("implement me")
+}
+
+func (c *NutsDB) Del(key string) error {
+	panic("implement me")
+}
+
+func (c *NutsDB) GetMulti(keys []string) map[string]interface{} {
+	panic("implement me")
+}
+
+func (c *NutsDB) SetMulti(values map[string]interface{}, ttl time.Duration) (err error) {
+	panic("implement me")
+}
+
+func (c *NutsDB) DelMulti(keys []string) error {
+	panic("implement me")
+}
+
+func (c *NutsDB) Clear() error {
+	panic("implement me")
+}
+
+func (c *NutsDB) Close() error {
+	panic("implement me")
+}
+
+
diff --git a/redis/redis.go b/redis/redis.go
index 4fd862e..4286f38 100644
--- a/redis/redis.go
+++ b/redis/redis.go
@@ -5,9 +5,10 @@ package redis
 import (
 	"errors"
 	"fmt"
-	"github.com/gomodule/redigo/redis"
 	"log"
 	"time"
+
+	"github.com/gomodule/redigo/redis"
 )
 
 // RedisCache definition.
@@ -148,6 +149,11 @@ func (c *RedisCache) DelMulti(keys []string) (err error) {
 	return
 }
 
+// Close connections
+func (c *RedisCache) Close() error {
+	return c.pool.Close()
+}
+
 // Clear all caches
 func (c *RedisCache) Clear() error {
 	conn := c.pool.Get()
@@ -233,11 +239,11 @@ func newPool(url, password string, dbNum int) *redis.Pool {
 			if password != "" {
 				_, err := c.Do("AUTH", password)
 				if err != nil {
-					c.Close()
+					_= c.Close()
 					return nil, err
 				}
 			}
-			c.Do("SELECT", dbNum)
+			_,_ = c.Do("SELECT", dbNum)
 			return c, err
 		},
 		TestOnBorrow: func(c redis.Conn, t time.Time) error {
diff --git a/redis/redis_test.go b/redis/redis_test.go
index 9e20525..d9131cd 100644
--- a/redis/redis_test.go
+++ b/redis/redis_test.go
@@ -7,11 +7,13 @@ func Example() {
 	c := Connect("127.0.0.1:6379", "", 0)
 
 	// set
-	c.Set("name", "cache value", 60)
+	_= c.Set("name", "cache value", 60)
+
 	// get
 	val := c.Get("name")
+
 	// del
-	c.Del("name")
+	_= c.Del("name")
 
 	// get: "cache value"
 	fmt.Print(val)
diff --git a/testdata/.keep b/testdata/.keep
new file mode 100644
index 0000000..e69de29