feature extend readthrough for cache module (#5116)

* feature 增加readthrough

client/cache/memcache/memcache_test.go

@@ -16,6 +16,7 @@ package memcache
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"os"
 	"strconv"
@@ -23,6 +24,8 @@ import (
 	"testing"
 	"time"
 
+	"github.com/beego/beego/v2/core/berror"
+
 	_ "github.com/bradfitz/gomemcache/memcache"
 	"github.com/stretchr/testify/assert"
 
@@ -69,7 +72,7 @@ func TestMemcacheCache(t *testing.T) {
 	v, err = strconv.Atoi(string(val.([]byte)))
 	assert.Nil(t, err)
 	assert.Equal(t, 1, v)
-	bm.Delete(context.Background(), "astaxie")
+	assert.Nil(t, bm.Delete(context.Background(), "astaxie"))
 
 	res, _ = bm.IsExist(context.Background(), "astaxie")
 	assert.False(t, res)
@@ -111,3 +114,116 @@ func TestMemcacheCache(t *testing.T) {
 	assert.Nil(t, bm.ClearAll(context.Background()))
 	// test clear all
 }
+
+func TestReadThroughCache_Memcache_Get(t *testing.T) {
+	bm, err := cache.NewCache("memcache", fmt.Sprintf(`{"conn": "%s"}`, "127.0.0.1:11211"))
+	assert.Nil(t, err)
+
+	testReadThroughCacheGet(t, bm)
+}
+
+func testReadThroughCacheGet(t *testing.T, bm cache.Cache) {
+	testCases := []struct {
+		name    string
+		key     string
+		value   string
+		cache   cache.Cache
+		wantErr error
+	}{
+		{
+			name: "Get load err",
+			key:  "key0",
+			cache: func() cache.Cache {
+				kvs := map[string]any{"key0": "value0"}
+				db := &MockOrm{kvs: kvs}
+				loadfunc := func(ctx context.Context, key string) (any, error) {
+					v, er := db.Load(key)
+					if er != nil {
+						return nil, er
+					}
+					val := []byte(v.(string))
+					return val, nil
+				}
+				c, err := cache.NewReadThroughCache(bm, 3*time.Second, loadfunc)
+				assert.Nil(t, err)
+				return c
+			}(),
+			wantErr: func() error {
+				err := errors.New("the key not exist")
+				return berror.Wrap(
+					err, cache.LoadFuncFailed, "cache unable to load data")
+			}(),
+		},
+		{
+			name:  "Get cache exist",
+			key:   "key1",
+			value: "value1",
+			cache: func() cache.Cache {
+				keysMap := map[string]int{"key1": 1}
+				kvs := map[string]any{"key1": "value1"}
+				db := &MockOrm{keysMap: keysMap, kvs: kvs}
+				loadfunc := func(ctx context.Context, key string) (any, error) {
+					v, er := db.Load(key)
+					if er != nil {
+						return nil, er
+					}
+					val := []byte(v.(string))
+					return val, nil
+				}
+				c, err := cache.NewReadThroughCache(bm, 3*time.Second, loadfunc)
+				assert.Nil(t, err)
+				err = c.Put(context.Background(), "key1", "value1", 3*time.Second)
+				assert.Nil(t, err)
+				return c
+			}(),
+		},
+		{
+			name:  "Get loadFunc exist",
+			key:   "key2",
+			value: "value2",
+			cache: func() cache.Cache {
+				keysMap := map[string]int{"key2": 1}
+				kvs := map[string]any{"key2": "value2"}
+				db := &MockOrm{keysMap: keysMap, kvs: kvs}
+				loadfunc := func(ctx context.Context, key string) (any, error) {
+					v, er := db.Load(key)
+					if er != nil {
+						return nil, er
+					}
+					val := []byte(v.(string))
+					return val, nil
+				}
+				c, err := cache.NewReadThroughCache(bm, 3*time.Second, loadfunc)
+				assert.Nil(t, err)
+				return c
+			}(),
+		},
+	}
+	_, err := cache.NewReadThroughCache(bm, 3*time.Second, nil)
+	assert.Equal(t, berror.Error(cache.InvalidLoadFunc, "loadFunc cannot be nil"), err)
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			bs := []byte(tc.value)
+			c := tc.cache
+			val, err := c.Get(context.Background(), tc.key)
+			if err != nil {
+				assert.EqualError(t, tc.wantErr, err.Error())
+				return
+			}
+			assert.Equal(t, bs, val)
+		})
+	}
+}
+
+type MockOrm struct {
+	keysMap map[string]int
+	kvs     map[string]any
+}
+
+func (m *MockOrm) Load(key string) (any, error) {
+	_, ok := m.keysMap[key]
+	if !ok {
+		return nil, errors.New("the key not exist")
+	}
+	return m.kvs[key], nil
+}