From f16d5646f013810820a9a4bd74c050d9abe137f3 Mon Sep 17 00:00:00 2001
From: Michael Wan <zirenwan@gmail.com>
Date: Wed, 31 Oct 2018 01:38:42 -0400
Subject: [PATCH] feature: add Close func for Store backend

Signed-off-by: Michael Wan <zirenwan@gmail.com>
---
 pkg/meta/backend.go    |  4 ++++
 pkg/meta/boltdb.go     |  6 ++++++
 pkg/meta/local.go      |  5 +++++
 pkg/meta/store.go      |  5 +++++
 pkg/meta/store_test.go | 13 +++++++++++++
 5 files changed, 33 insertions(+)

diff --git a/pkg/meta/backend.go b/pkg/meta/backend.go
index 17265ae6be..84358eb4e5 100644
--- a/pkg/meta/backend.go
+++ b/pkg/meta/backend.go
@@ -24,6 +24,10 @@ type Backend interface {
 
 	// Path returns the path with the specified key.
 	Path(key string) string
+
+	// Close releases all resources used by the store
+	// It does not make any changes to store.
+	Close() error
 }
 
 // Register registers a backend to be daemon's store.
diff --git a/pkg/meta/boltdb.go b/pkg/meta/boltdb.go
index 45049c24a6..d5f996f31b 100644
--- a/pkg/meta/boltdb.go
+++ b/pkg/meta/boltdb.go
@@ -160,3 +160,9 @@ func (b *bolt) List(bucket string) ([][]byte, error) {
 
 	return values, err
 }
+
+// Close releases all database resources.
+// All transactions must be closed before closing the database.
+func (b *bolt) Close() error {
+	return b.db.Close()
+}
diff --git a/pkg/meta/local.go b/pkg/meta/local.go
index f6cbd1dec6..727d6c3e5e 100644
--- a/pkg/meta/local.go
+++ b/pkg/meta/local.go
@@ -177,6 +177,11 @@ func (s *localStore) Keys(fileName string) ([]string, error) {
 	return keys, nil
 }
 
+// Close do nothing in local store
+func (s *localStore) Close() error {
+	return nil
+}
+
 func mkdirIfNotExist(dir string) error {
 	if _, err := os.Stat(dir); err != nil {
 		if os.IsNotExist(err) {
diff --git a/pkg/meta/store.go b/pkg/meta/store.go
index fb2b6afca7..13a034306b 100644
--- a/pkg/meta/store.go
+++ b/pkg/meta/store.go
@@ -270,3 +270,8 @@ func (s *Store) KeysWithPrefix(prefix string) ([]string, error) {
 func (s *Store) Path(key string) string {
 	return s.backend.Path(key)
 }
+
+// Shutdown releases all resources used by the backend
+func (s *Store) Shutdown() error {
+	return s.backend.Close()
+}
diff --git a/pkg/meta/store_test.go b/pkg/meta/store_test.go
index c5ad138cde..7ce8d74ea4 100644
--- a/pkg/meta/store_test.go
+++ b/pkg/meta/store_test.go
@@ -1,6 +1,7 @@
 package meta
 
 import (
+	"fmt"
 	"reflect"
 	"testing"
 )
@@ -201,6 +202,18 @@ func TestBoltdbRemove(t *testing.T) {
 	}
 }
 
+func TestBoltdbClose(t *testing.T) {
+	if err := boltdbStore.Shutdown(); err != nil {
+		t.Fatal(err)
+	}
+
+	// test List again, should occur error here
+	_, err := boltdbStore.List()
+	if err == nil {
+		t.Fatal(fmt.Errorf("still can visit the boltdb after execute close db action"))
+	}
+}
+
 type Demo4 struct {
 	A int
 	B string