Merge pull request #370 from sljeff/cache

remove cacheNil support, may add it back if we can find a better way to support this feature in the future

docs/CHANGELOG.md

@@ -1,3 +1,12 @@
+# 1.0.0 (2022-01-05)
+
+- 删除 cachext 的 cacheNil 逻辑
+
+**BREAKING CHANGE**:
+
+- 去掉 WithCacheNil 配置
+- 以前判断了 cachext.Nil 的地方，应该改为判断响应后 out 值是否为空值
+
 # 0.16.3 (2021-10-09)
 
 - 修正 `DialOptions` 拼写

extensions/cachext/cached.go

@@ -13,16 +13,9 @@ import (
 	"github.com/prometheus/client_golang/prometheus"
 )
 
-const Nil = cacheNil("cache result is nil")
-
-type cacheNil string
-
-func (e cacheNil) Error() string { return string(e) }
-
 // CachedConfig save the param and config for a cached func
 type CachedConfig struct {
 	cache        *CacheExt
-	cacheNil     bool
 	ttl          time.Duration
 	version      int64
 	funcName     string
@@ -72,46 +65,22 @@ func (c *CachedConfig) GetResult(ctx context.Context, out interface{}, strArgs [
 			// Increment hit counter.
 			c.cache.hitCounter.With(labels).Inc()
 		}
-		if c.cacheNil && decodeIsNil(data) {
-			// 无法直接把out设置为nil，这里通过返回特殊的错误来表示nil。调用方需要判断
-			return Nil
-		}
 		return decode(data, out)
 	}
 	res, err := c.getResult(ctx, strArgs, intArgs)
 	if err != nil {
 		return err
 	}
-	// 函数返回值与cacheNil需要设置的值相同，报错
-	if c.cacheNil && decodeIsNil(res) {
-		return errors.New("Your response is conflict with cacheNil value")
-	}
-
-	status := [2]bool{res == nil, c.cacheNil} // 函数返回值与是否cacheNil状态判断
-	cacheNilHited := [2]bool{true, true}      // 函数返回值是nil，同时cacheNil。
-	noNeedCacheNil := [2]bool{true, false}    // 函数返回值是nil，不cacheNil。
 
-	switch status {
-	case cacheNilHited:
-		// Set nil 会保存一个[]byte{192}的结构到backend中
-		nilBytes, _ := encode(nil)
-		if err = c.cache.backend.Set(ctx, c.cache.transKey(cacheKey), nilBytes, c.ttl); err != nil {
-			return err
-		}
-		return Nil
-	case noNeedCacheNil:
-		return Nil
-	default:
-		// 函数返回值非空，把结果放入缓存。不管是否cacheNil
-		if encodedBytes, err := encode(res); err != nil {
+	// 把结果放入缓存
+	if encodedBytes, err := encode(res); err != nil {
+		return err
+	} else {
+		err = c.cache.backend.Set(ctx, c.cache.transKey(cacheKey), encodedBytes, c.ttl)
+		if err != nil {
 			return err
-		} else {
-			err = c.cache.backend.Set(ctx, c.cache.transKey(cacheKey), encodedBytes, c.ttl)
-			if err != nil {
-				return err
-			}
-			return decode(encodedBytes, out)
 		}
+		return decode(encodedBytes, out)
 	}
 }
 
@@ -125,7 +94,6 @@ func (c *CacheExt) Cached(funcName string, f cachedFunc, options ...cacheOption)
 	c.cachedFuncName[funcName] = void{}
 	cacheFuncConf := &CachedConfig{
 		ttl:          24 * 2 * time.Hour,
-		cacheNil:     false,
 		version:      1,
 		cache:        c,
 		getResult:    f,
@@ -160,15 +128,6 @@ func WithVersion(version int64) cacheOption {
 	}
 }
 
-// WithCacheNil set whether cacheNil to cacheFuncConfig, if cacheNil seted and function returns nil, GetResult will return Nil
-// cacheNil stored in redis with []byte{192} 0xC0
-func WithCacheNil(cacheNil bool) cacheOption {
-	return func(config *CachedConfig) error {
-		config.cacheNil = cacheNil
-		return nil
-	}
-}
-
 // WithMakeCacheKey you can write your own makeCacheKey, use this func to change the default makeCacheKey.
 // first param means funcName, the second param means version, next params mean real function input param.
 func WithMakeCacheKey(f makeCacheKeyFunc) cacheOption {

extensions/cachext/ext.go

@@ -1,7 +1,6 @@
 package cachext
 
 import (
-	"bytes"
 	"context"
 	"errors"
 	"fmt"
@@ -248,14 +247,6 @@ func decode(data []byte, out interface{}) error {
 	return msgpack.Unmarshal(data, out)
 }
 
-func decodeIsNil(data interface{}) bool {
-	if byteData, ok := data.([]byte); ok {
-		err := msgpack.NewDecoder(bytes.NewReader(byteData)).DecodeNil()
-		return (err == nil)
-	}
-	return false
-}
-
 // Create a collector for total cache request counter
 func newCacheRequestCounter() *prometheus.CounterVec {
 	return promauto.NewCounterVec(

extensions/cachext/ext_test.go

@@ -152,7 +152,7 @@ func TestCacheExt_Operation(t *testing.T) {
 	mydata := myData{}
 	mydata.Value1 = 100
 	mydata.Value2 = "thre si a verty conplex data {}{}"
-	mydata.Value3 = []node{node{"这是第一个node", []string{"id1", "id2", "id3"}}, node{"这是第二个node", []string{"id4", "id5", "id6"}}}
+	mydata.Value3 = []node{{"这是第一个node", []string{"id1", "id2", "id3"}}, {"这是第二个node", []string{"id4", "id5", "id6"}}}
 	if err := cache.Set(context.Background(), "cache_key_2", mydata, 10*time.Second); err != nil {
 		t.Log(err)
 		t.Errorf("Cache Set Failed")
@@ -392,45 +392,34 @@ func TestCacheExt_Cached_Common(t *testing.T) {
 	// nil
 	f_nil := func(_ context.Context, names []string, arg []int64) (interface{}, error) {
 		call_times += 1
-		return nil, nil
+		return func() (*string, error) {
+			return nil, nil
+		}()
 	}
-	c_f_nil := cache.Cached("f_nil", f_nil, cachext.WithVersion(2), cachext.WithTTL(10*time.Second), cachext.WithCacheNil(false))
-	nil_res := ""
+	c_f_nil := cache.Cached("f_nil", f_nil, cachext.WithVersion(2), cachext.WithTTL(10*time.Second))
+	nil_res := "content"
 	call_times = 0
 	for i := 0; i <= 3; i++ {
 		err := c_f_nil.GetResult(context.Background(), &nil_res, []string{}, []int64{})
-		if err != cachext.Nil {
-			t.Errorf("Not Cache Nil failed")
+		if err != nil || nil_res != "" {
+			t.Errorf(err.Error())
 		}
 	}
 	if call_times != 4 {
 		t.Log(nil_res, call_times)
 	}
-	cn_f_nil := cache.Cached("cn_f_nil", f_nil, cachext.WithVersion(5), cachext.WithTTL(10*time.Second), cachext.WithCacheNil(true))
+	nil_res = "content"
+	cn_f_nil := cache.Cached("cn_f_nil", f_nil, cachext.WithVersion(5), cachext.WithTTL(10*time.Second))
 	call_times = 0
 	for i := 0; i <= 3; i++ {
 		err := cn_f_nil.GetResult(context.Background(), &nil_res, []string{}, []int64{})
-		if err != cachext.Nil {
-			t.Errorf("Cache Nil failed")
+		if err != nil || nil_res != "" {
+			t.Errorf(err.Error())
 		}
 	}
 	if call_times != 1 {
 		t.Log(nil_res, call_times)
 	}
-	// nil 测试函数返回值与cacheNil预设值冲突时，报错情况
-	f_evil_nil := func(_ context.Context, names []string, arg []int64) (interface{}, error) {
-		return []byte{192}, nil
-	}
-	c_f_evil_nil := cache.Cached("f_evil_nil", f_evil_nil, cachext.WithTTL(10*time.Second), cachext.WithVersion(2), cachext.WithCacheNil(true))
-	if err := c_f_evil_nil.GetResult(context.Background(), &nil_res, []string{}, []int64{}); err == nil {
-		t.Log(nil_res, err, call_times)
-		t.Errorf("Evil Cache Nil happened")
-	}
-	c_f_kind_nil := cache.Cached("c_f_kind_nil", f_evil_nil, cachext.WithTTL(10*time.Second), cachext.WithVersion(2))
-	if err := c_f_kind_nil.GetResult(context.Background(), &nil_res, []string{}, []int64{}); err != nil {
-		t.Log(nil_res, err, call_times)
-		t.Errorf("Evil Cache Nil happened")
-	}
 }
 
 func TestCacheExt_Cached_Struct(t *testing.T) {
@@ -463,7 +452,7 @@ func TestCacheExt_Cached_Struct(t *testing.T) {
 		mydata.Value2 = "thre si a verty conplex data {}{}"
 		some_str := "some str"
 		mydata.Value4 = some_str
-		mydata.Value3 = []node{node{"这是第一个node", []string{"id1", "id2", "id3"}}, node{"这是第二个node", []string{"id4", "id5", "id6"}}}
+		mydata.Value3 = []node{{"这是第一个node", []string{"id1", "id2", "id3"}}, {"这是第二个node", []string{"id4", "id5", "id6"}}}
 		return mydata, nil
 	}
 	cached_complex_ff := cache.Cached("complex_ff", complex_ff, cachext.WithTTL(10*time.Second))