feature add singleflight cache (#5119)

client/cache/error_code.go

@@ -123,6 +123,15 @@ var InvalidSsdbCacheValue = berror.DefineCode(4002022, moduleName, "InvalidSsdbC
 SSDB cache only accept string value. Please check your input.
 `)
 
+var InvalidLoadFunc = berror.DefineCode(4002023, moduleName, "InvalidLoadFunc", `
+Invalid load function for read-through pattern decorator.
+You should pass a valid(non-nil) load function when initiate the decorator instance.
+`)
+
+var LoadFuncFailed = berror.DefineCode(4002024, moduleName, "LoadFuncFailed", `
+Failed to load data, please check whether the loadfunc is correct
+`)
+
 var InvalidInitParameters = berror.DefineCode(4002025, moduleName, "InvalidInitParameters", `
 Invalid init cache parameters.
 You can check the related function to confirm that if you pass correct parameters or configure to initiate a Cache instance.
@@ -133,15 +142,6 @@ Failed to execute the StoreFunc.
 Please check the log to make sure the StoreFunc works for the specific key and value.
 `)
 
-var InvalidLoadFunc = berror.DefineCode(4002023, moduleName, "InvalidLoadFunc", `
-Invalid load function for read-through pattern decorator.
-You should pass a valid(non-nil) load function when initiate the decorator instance.
-`)
-
-var LoadFuncFailed = berror.DefineCode(4002024, moduleName, "InvalidLoadFunc", `
-Failed to load data, please check whether the loadfunc is correct
-`)
-
 var DeleteFileCacheItemFailed = berror.DefineCode(5002001, moduleName, "DeleteFileCacheItemFailed", `
 Beego try to delete file cache item failed. 
 Please check whether Beego generated file correctly. 

client/cache/singleflight.go

@@ -0,0 +1,63 @@
+// Copyright 2014 beego Author. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cache
+
+import (
+	"context"
+	"time"
+
+	"github.com/beego/beego/v2/core/berror"
+	"golang.org/x/sync/singleflight"
+)
+
+// SingleflightCache
+// This is a very simple decorator mode
+type SingleflightCache struct {
+	Cache
+	group      *singleflight.Group
+	expiration time.Duration
+	loadFunc   func(ctx context.Context, key string) (any, error)
+}
+
+// NewSingleflightCache create SingleflightCache
+func NewSingleflightCache(c Cache, expiration time.Duration,
+	loadFunc func(ctx context.Context, key string) (any, error),
+) (Cache, error) {
+	if loadFunc == nil {
+		return nil, berror.Error(InvalidLoadFunc, "loadFunc cannot be nil")
+	}
+	return &SingleflightCache{
+		Cache:      c,
+		group:      &singleflight.Group{},
+		expiration: expiration,
+		loadFunc:   loadFunc,
+	}, nil
+}
+
+// Get In the Get method, single flight is used to load data and write back the cache.
+func (s *SingleflightCache) Get(ctx context.Context, key string) (any, error) {
+	val, err := s.Cache.Get(ctx, key)
+	if val == nil || err != nil {
+		val, err, _ = s.group.Do(key, func() (interface{}, error) {
+			v, er := s.loadFunc(ctx, key)
+			if er != nil {
+				return nil, berror.Wrap(er, LoadFuncFailed, "cache unable to load data")
+			}
+			er = s.Cache.Put(ctx, key, v, s.expiration)
+			return v, er
+		})
+	}
+	return val, err
+}

client/cache/singleflight_test.go

@@ -0,0 +1,72 @@
+// Copyright 2014 beego Author. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cache
+
+import (
+	"context"
+	"sync"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestSingleflight_Memory_Get(t *testing.T) {
+	bm, err := NewCache("memory", `{"interval":20}`)
+	assert.Nil(t, err)
+
+	testSingleflightCacheConcurrencyGet(t, bm)
+}
+
+func TestSingleflight_file_Get(t *testing.T) {
+	fc := NewFileCache().(*FileCache)
+	fc.CachePath = "////aaa"
+	err := fc.Init()
+	assert.NotNil(t, err)
+	fc.CachePath = getTestCacheFilePath()
+	err = fc.Init()
+	assert.Nil(t, err)
+
+	testSingleflightCacheConcurrencyGet(t, fc)
+}
+
+func testSingleflightCacheConcurrencyGet(t *testing.T, bm Cache) {
+	key, value := "key3", "value3"
+	db := &MockOrm{keysMap: map[string]int{key: 1}, kvs: map[string]any{key: value}}
+	c, err := NewSingleflightCache(bm, 10*time.Second,
+		func(ctx context.Context, key string) (any, error) {
+			val, er := db.Load(key)
+			if er != nil {
+				return nil, er
+			}
+			return val, nil
+		})
+	assert.Nil(t, err)
+
+	var wg sync.WaitGroup
+	wg.Add(10)
+	for i := 0; i < 10; i++ {
+		go func() {
+			defer wg.Done()
+			val, err := c.Get(context.Background(), key)
+			if err != nil {
+				t.Error(err)
+			}
+			assert.Equal(t, value, val)
+		}()
+		time.Sleep(1 * time.Millisecond)
+	}
+	wg.Wait()
+}

client/cache/write_through_test.go

@@ -27,7 +27,7 @@ import (
 )
 
 func TestWriteThoughCache_Set(t *testing.T) {
-	var mockDbStore = make(map[string]any)
+	mockDbStore := make(map[string]any)
 
 	testCases := []struct {
 		name      string