diff --git a/.github/workflows/go.yml b/.github/workflows/go.yml
index d2a527c6b..ebd64e90b 100644
--- a/.github/workflows/go.yml
+++ b/.github/workflows/go.yml
@@ -44,7 +44,7 @@ jobs:
     steps:
       - uses: actions/checkout@v3
       - name: Set up Go
-        uses: actions/setup-go@v3.3.0
+        uses: actions/setup-go@v3.3.1
         with:
           go-version: ${{ matrix.go }}
 
diff --git a/api/metadata/server.go b/api/metadata/server.go
index 3600fc14e..b1c4c17b2 100644
--- a/api/metadata/server.go
+++ b/api/metadata/server.go
@@ -7,6 +7,7 @@ import (
 	"errors"
 	"fmt"
 	"io"
+	"sort"
 	"sync"
 
 	"google.golang.org/grpc"
@@ -115,6 +116,8 @@ func (s *Server) ListServices(ctx context.Context, in *ListServicesRequest) (*Li
 			reply.Methods = append(reply.Methods, fmt.Sprintf("/%s/%s", name, method))
 		}
 	}
+	sort.Strings(reply.Services)
+	sort.Strings(reply.Methods)
 	return reply, nil
 }
 
diff --git a/cmd/kratos/internal/base/vcs_url.go b/cmd/kratos/internal/base/vcs_url.go
index ef76db30f..6d3aef12a 100644
--- a/cmd/kratos/internal/base/vcs_url.go
+++ b/cmd/kratos/internal/base/vcs_url.go
@@ -8,7 +8,7 @@ import (
 )
 
 var (
-	scpSyntaxRe = regexp.MustCompile(`^([a-zA-Z0-9_]+)@([a-zA-Z0-9._-]+):(.*)$`)
+	scpSyntaxRe = regexp.MustCompile(`^(\w+)@([\w.-]+):(.*)$`)
 	scheme      = []string{"git", "https", "http", "git+ssh", "ssh", "file", "ftp", "ftps"}
 )
 
diff --git a/cmd/kratos/internal/change/get.go b/cmd/kratos/internal/change/get.go
index 18e02072a..32046d1ea 100644
--- a/cmd/kratos/internal/change/get.go
+++ b/cmd/kratos/internal/change/get.go
@@ -43,7 +43,7 @@ func (g *GithubAPI) GetReleaseInfo(version string) ReleaseInfo {
 	if version != "latest" {
 		api = fmt.Sprintf("https://api.github.com/repos/%s/%s/releases/tags/%s", g.Owner, g.Repo, version)
 	}
-	resp, code := requestGithubAPI(api, "GET", nil, g.Token)
+	resp, code := requestGithubAPI(api, http.MethodGet, nil, g.Token)
 	if code != http.StatusOK {
 		printGithubErrorInfo(resp)
 	}
@@ -63,7 +63,7 @@ func (g *GithubAPI) GetCommitsInfo() []CommitInfo {
 	var list []CommitInfo
 	for {
 		url := fmt.Sprintf("https://api.github.com/repos/%s/%s/commits?pre_page=%d&page=%d&since=%s", g.Owner, g.Repo, prePage, page, info.PublishedAt)
-		resp, code := requestGithubAPI(url, "GET", nil, g.Token)
+		resp, code := requestGithubAPI(url, http.MethodGet, nil, g.Token)
 		if code != http.StatusOK {
 			printGithubErrorInfo(resp)
 		}
diff --git a/cmd/kratos/version.go b/cmd/kratos/version.go
index a616f7153..5ccc1597e 100644
--- a/cmd/kratos/version.go
+++ b/cmd/kratos/version.go
@@ -1,4 +1,4 @@
 package main
 
 // release is the current kratos tool version.
-const release = "v2.5.1"
+const release = "v2.5.2"
diff --git a/cmd/protoc-gen-go-errors/version.go b/cmd/protoc-gen-go-errors/version.go
index 8061323f7..e9c17d212 100644
--- a/cmd/protoc-gen-go-errors/version.go
+++ b/cmd/protoc-gen-go-errors/version.go
@@ -1,4 +1,4 @@
 package main
 
 // release is the current protoc-gen-go-errors version.
-const release = "v2.5.1"
+const release = "v2.5.2"
diff --git a/cmd/protoc-gen-go-http/http.go b/cmd/protoc-gen-go-http/http.go
index d88277227..1c9298bf7 100644
--- a/cmd/protoc-gen-go-http/http.go
+++ b/cmd/protoc-gen-go-http/http.go
@@ -2,6 +2,7 @@ package main
 
 import (
 	"fmt"
+	"net/http"
 	"os"
 	"regexp"
 	"strings"
@@ -85,7 +86,7 @@ func genService(gen *protogen.Plugin, file *protogen.File, g *protogen.Generated
 			sd.Methods = append(sd.Methods, buildHTTPRule(g, method, rule))
 		} else if !omitempty {
 			path := fmt.Sprintf("/%s/%s", service.Desc.FullName(), method.Desc.Name())
-			sd.Methods = append(sd.Methods, buildMethodDesc(g, method, "POST", path))
+			sd.Methods = append(sd.Methods, buildMethodDesc(g, method, http.MethodPost, path))
 		}
 	}
 	if len(sd.Methods) != 0 {
@@ -119,19 +120,19 @@ func buildHTTPRule(g *protogen.GeneratedFile, m *protogen.Method, rule *annotati
 	switch pattern := rule.Pattern.(type) {
 	case *annotations.HttpRule_Get:
 		path = pattern.Get
-		method = "GET"
+		method = http.MethodGet
 	case *annotations.HttpRule_Put:
 		path = pattern.Put
-		method = "PUT"
+		method = http.MethodPut
 	case *annotations.HttpRule_Post:
 		path = pattern.Post
-		method = "POST"
+		method = http.MethodPost
 	case *annotations.HttpRule_Delete:
 		path = pattern.Delete
-		method = "DELETE"
+		method = http.MethodDelete
 	case *annotations.HttpRule_Patch:
 		path = pattern.Patch
-		method = "PATCH"
+		method = http.MethodPatch
 	case *annotations.HttpRule_Custom:
 		path = pattern.Custom.Path
 		method = pattern.Custom.Kind
@@ -139,7 +140,7 @@ func buildHTTPRule(g *protogen.GeneratedFile, m *protogen.Method, rule *annotati
 	body = rule.Body
 	responseBody = rule.ResponseBody
 	md := buildMethodDesc(g, m, method, path)
-	if method == "GET" || method == "DELETE" {
+	if method == http.MethodGet || method == http.MethodDelete {
 		if body != "" {
 			_, _ = fmt.Fprintf(os.Stderr, "\u001B[31mWARN\u001B[m: %s %s body should not be declared.\n", method, path)
 		}
@@ -213,7 +214,7 @@ func buildPathVars(path string) (res map[string]*string) {
 	if strings.HasSuffix(path, "/") {
 		fmt.Fprintf(os.Stderr, "\u001B[31mWARN\u001B[m: Path %s should not end with \"/\" \n", path)
 	}
-	pattern := regexp.MustCompile(`(?i){([a-z\.0-9_\s]*)=?([^{}]*)}`)
+	pattern := regexp.MustCompile(`(?i){([a-z.0-9_\s]*)=?([^{}]*)}`)
 	matches := pattern.FindAllStringSubmatch(path, -1)
 	res = make(map[string]*string, len(matches))
 	for _, m := range matches {
diff --git a/cmd/protoc-gen-go-http/version.go b/cmd/protoc-gen-go-http/version.go
index 25b73c2fe..7d929e189 100644
--- a/cmd/protoc-gen-go-http/version.go
+++ b/cmd/protoc-gen-go-http/version.go
@@ -1,4 +1,4 @@
 package main
 
 // release is the current protoc-gen-go-http version.
-const release = "v2.5.1"
+const release = "v2.5.2"
diff --git a/contrib/config/apollo/README.md b/contrib/config/apollo/README.md
index c03cff0fd..a8eea4932 100644
--- a/contrib/config/apollo/README.md
+++ b/contrib/config/apollo/README.md
@@ -97,5 +97,4 @@ config := map[string]interface{}{
         }
     }
 }
-_ = config
 ```
diff --git a/contrib/config/apollo/apollo.go b/contrib/config/apollo/apollo.go
index 259ed1a90..bd96ef11d 100644
--- a/contrib/config/apollo/apollo.go
+++ b/contrib/config/apollo/apollo.go
@@ -3,15 +3,14 @@ package apollo
 import (
 	"strings"
 
-	"github.com/go-kratos/kratos/v2/config"
-	"github.com/go-kratos/kratos/v2/log"
-
 	"github.com/apolloconfig/agollo/v4"
 	"github.com/apolloconfig/agollo/v4/constant"
 	apolloConfig "github.com/apolloconfig/agollo/v4/env/config"
 	"github.com/apolloconfig/agollo/v4/extension"
 
+	"github.com/go-kratos/kratos/v2/config"
 	"github.com/go-kratos/kratos/v2/encoding"
+	"github.com/go-kratos/kratos/v2/log"
 )
 
 type apollo struct {
diff --git a/contrib/config/apollo/watcher.go b/contrib/config/apollo/watcher.go
index 94ef2ef0b..ea5ef1083 100644
--- a/contrib/config/apollo/watcher.go
+++ b/contrib/config/apollo/watcher.go
@@ -4,12 +4,11 @@ import (
 	"context"
 	"strings"
 
-	"github.com/go-kratos/kratos/v2/encoding"
+	"github.com/apolloconfig/agollo/v4/storage"
 
 	"github.com/go-kratos/kratos/v2/config"
+	"github.com/go-kratos/kratos/v2/encoding"
 	"github.com/go-kratos/kratos/v2/log"
-
-	"github.com/apolloconfig/agollo/v4/storage"
 )
 
 type watcher struct {
diff --git a/contrib/config/consul/README.md b/contrib/config/consul/README.md
index a3d39a18a..9dc5a0666 100644
--- a/contrib/config/consul/README.md
+++ b/contrib/config/consul/README.md
@@ -2,20 +2,21 @@
 
 ```go
 import (
-    "github.com/go-kratos/kratos/contrib/config/consul/v2"
     "github.com/hashicorp/consul/api"
+
+    "github.com/go-kratos/kratos/contrib/config/consul/v2"
 )
-func main() {
 
+func main() {
     consulClient, err := api.NewClient(&api.Config{
-    Address: "127.0.0.1:8500",
+        Address: "127.0.0.1:8500",
     })
     if err != nil {
         panic(err)
     }
     cs, err := consul.New(consulClient, consul.WithPath("app/cart/configs/"))
-    //consul中需要标注文件后缀，kratos读取配置需要适配文件后缀
-    //The file suffix needs to be marked, and kratos needs to adapt the file suffix to read the configuration.
+    // consul中需要标注文件后缀，kratos读取配置需要适配文件后缀
+    // The file suffix needs to be marked, and kratos needs to adapt the file suffix to read the configuration.
     if err != nil {
         panic(err)
     }
diff --git a/contrib/config/etcd/README.md b/contrib/config/etcd/README.md
index d76687458..131619c1a 100644
--- a/contrib/config/etcd/README.md
+++ b/contrib/config/etcd/README.md
@@ -4,10 +4,11 @@
 import (
 	"log"
 
-	cfg "github.com/go-kratos/kratos/contrib/config/etcd/v2"
-	"github.com/go-kratos/kratos/v2/config"
 	clientv3 "go.etcd.io/etcd/client/v3"
 	"google.golang.org/grpc"
+
+	cfg "github.com/go-kratos/kratos/contrib/config/etcd/v2"
+	"github.com/go-kratos/kratos/v2/config"
 )
 
 // create an etcd client
@@ -30,12 +31,16 @@ if err != nil {
 c := config.New(config.WithSource(source))
 defer c.Close()
 
+// load sources before get
+if err := c.Load(); err != nil {
+    log.Fatalln(err)
+}
+
 // acquire config value
 foo, err := c.Value("/app-config").String()
 if err != nil {
-    log.Println(err)
+    log.Fatalln(err)
 }
-println(foo)
 
+log.Println(foo)
 ```
-
diff --git a/contrib/config/kubernetes/config_test.go b/contrib/config/kubernetes/config_test.go
index 6cdb1c98c..b110b634d 100644
--- a/contrib/config/kubernetes/config_test.go
+++ b/contrib/config/kubernetes/config_test.go
@@ -8,14 +8,14 @@ import (
 	"strings"
 	"testing"
 
-	"github.com/go-kratos/kratos/v2/config"
-
 	v1 "k8s.io/api/core/v1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/client-go/kubernetes"
 	"k8s.io/client-go/rest"
 	"k8s.io/client-go/tools/clientcmd"
 	"k8s.io/client-go/util/homedir"
+
+	"github.com/go-kratos/kratos/v2/config"
 )
 
 const (
diff --git a/contrib/config/nacos/README.md b/contrib/config/nacos/README.md
index 71f186bf6..fa54caf07 100644
--- a/contrib/config/nacos/README.md
+++ b/contrib/config/nacos/README.md
@@ -2,9 +2,10 @@
 
 ```go
 import (
-	kconfig "github.com/go-kratos/kratos/v2/config"
 	"github.com/nacos-group/nacos-sdk-go/clients"
 	"github.com/nacos-group/nacos-sdk-go/common/constant"
+
+	kconfig "github.com/go-kratos/kratos/v2/config"
 )
 
 
diff --git a/contrib/config/nacos/go.mod b/contrib/config/nacos/go.mod
index 7890e0587..6917f24a4 100644
--- a/contrib/config/nacos/go.mod
+++ b/contrib/config/nacos/go.mod
@@ -5,6 +5,9 @@ go 1.16
 require (
 	github.com/go-kratos/kratos/v2 v2.4.0
 	github.com/nacos-group/nacos-sdk-go v1.0.9
+)
+
+require (
 	gopkg.in/yaml.v3 v3.0.1 // indirect
 )
 
diff --git a/contrib/config/polaris/README.md b/contrib/config/polaris/README.md
index 4c2694c47..b39e78f22 100644
--- a/contrib/config/polaris/README.md
+++ b/contrib/config/polaris/README.md
@@ -2,24 +2,23 @@
 
 ```go
 import (
- "log"
-
- "github.com/polarismesh/polaris-go"
- "github.com/go-kratos/kratos/contrib/config/polaris/v2"
+	"log"
+	
+	"github.com/polarismesh/polaris-go"
+	
+	"github.com/go-kratos/kratos/contrib/config/polaris/v2"
 )
 
 func main() {
+    configApi, err := polaris.NewConfigAPI()
+    if err != nil {
+    	log.Fatalln(err)
+    }
 
- configApi, err := polaris.NewConfigAPI()
- if err != nil {
-  log.Fatalln(err)
- }
-
- source, err := New(&configApi, WithNamespace("default"), WithFileGroup("default"), WithFileName("default.yaml"))
-
- if err != nil {
-  log.Fatalln(err)
- }
- source.Load()
+    source, err := New(&configApi, WithNamespace("default"), WithFileGroup("default"), WithFileName("default.yaml"))
+    if err != nil {
+    	log.Fatalln(err)
+    }
+    source.Load()
 }
 ```
diff --git a/contrib/config/polaris/config.go b/contrib/config/polaris/config.go
index c3c39ecee..288db4383 100644
--- a/contrib/config/polaris/config.go
+++ b/contrib/config/polaris/config.go
@@ -6,9 +6,9 @@ import (
 	"path/filepath"
 	"strings"
 
-	"github.com/go-kratos/kratos/v2/config"
-
 	"github.com/polarismesh/polaris-go"
+
+	"github.com/go-kratos/kratos/v2/config"
 )
 
 // Option is polaris config option.
diff --git a/contrib/config/polaris/watcher.go b/contrib/config/polaris/watcher.go
index dcd890556..703055508 100644
--- a/contrib/config/polaris/watcher.go
+++ b/contrib/config/polaris/watcher.go
@@ -5,11 +5,11 @@ import (
 	"path/filepath"
 	"strings"
 
-	"github.com/go-kratos/kratos/v2/config"
-	"github.com/go-kratos/kratos/v2/log"
-
 	"github.com/polarismesh/polaris-go"
 	"github.com/polarismesh/polaris-go/pkg/model"
+
+	"github.com/go-kratos/kratos/v2/config"
+	"github.com/go-kratos/kratos/v2/log"
 )
 
 type Watcher struct {
@@ -28,7 +28,7 @@ func getFullPath(namespace string, fileGroup string, fileName string) string {
 	return fmt.Sprintf("%s/%s/%s", namespace, fileGroup, fileName)
 }
 
-func recieve(event model.ConfigFileChangeEvent) {
+func receive(event model.ConfigFileChangeEvent) {
 	meta := event.ConfigFileMetadata
 	ec := eventChanMap[getFullPath(meta.GetNamespace(), meta.GetFileGroup(), meta.GetFileName())]
 	defer func() {
@@ -42,7 +42,7 @@ func recieve(event model.ConfigFileChangeEvent) {
 }
 
 func newWatcher(configFile polaris.ConfigFile) *Watcher {
-	configFile.AddChangeListener(recieve)
+	configFile.AddChangeListener(receive)
 
 	fullPath := getFullPath(configFile.GetNamespace(), configFile.GetFileGroup(), configFile.GetFileName())
 	if _, ok := eventChanMap[fullPath]; !ok {
diff --git a/contrib/encoding/msgpack/go.mod b/contrib/encoding/msgpack/go.mod
index 5b6a1f7e9..7548f1744 100644
--- a/contrib/encoding/msgpack/go.mod
+++ b/contrib/encoding/msgpack/go.mod
@@ -3,7 +3,7 @@ module github.com/go-kratos/kratos/contrib/encoding/msgpack/v2
 go 1.16
 
 require (
-	github.com/go-kratos/kratos/v2 v2.5.1
+	github.com/go-kratos/kratos/v2 v2.5.2
 	github.com/vmihailenco/msgpack/v5 v5.3.5
 )
 
diff --git a/contrib/log/aliyun/aliyun.go b/contrib/log/aliyun/aliyun.go
index 351de69d9..836960e06 100644
--- a/contrib/log/aliyun/aliyun.go
+++ b/contrib/log/aliyun/aliyun.go
@@ -16,6 +16,7 @@ import (
 // Logger see more detail https://github.com/aliyun/aliyun-log-go-sdk
 type Logger interface {
 	log.Logger
+
 	GetProducer() *producer.Producer
 	Close() error
 }
@@ -81,22 +82,16 @@ func (a *aliyunLog) Close() error {
 }
 
 func (a *aliyunLog) Log(level log.Level, keyvals ...interface{}) error {
-	buf := level.String()
-	levelTitle := "level"
-
-	contents := make([]*sls.LogContent, 0)
+	contents := make([]*sls.LogContent, 0, len(keyvals)/2+1)
 
 	contents = append(contents, &sls.LogContent{
-		Key:   &levelTitle,
-		Value: &buf,
+		Key:   newString(level.Key()),
+		Value: newString(level.String()),
 	})
-
 	for i := 0; i < len(keyvals); i += 2 {
-		key := toString(keyvals[i])
-		value := toString(keyvals[i+1])
 		contents = append(contents, &sls.LogContent{
-			Key:   &key,
-			Value: &value,
+			Key:   newString(toString(keyvals[i])),
+			Value: newString(toString(keyvals[i+1])),
 		})
 	}
 
@@ -104,9 +99,7 @@ func (a *aliyunLog) Log(level log.Level, keyvals ...interface{}) error {
 		Time:     proto.Uint32(uint32(time.Now().Unix())),
 		Contents: contents,
 	}
-
-	err := a.producer.SendLog(a.opts.project, a.opts.logstore, "", "", logInst)
-	return err
+	return a.producer.SendLog(a.opts.project, a.opts.logstore, "", "", logInst)
 }
 
 // NewAliyunLog new a aliyun logger with options.
@@ -128,6 +121,11 @@ func NewAliyunLog(options ...Option) Logger {
 	}
 }
 
+// newString string convert to *string
+func newString(s string) *string {
+	return &s
+}
+
 // toString convert any type to string
 func toString(v interface{}) string {
 	var key string
@@ -138,23 +136,23 @@ func toString(v interface{}) string {
 	case float64:
 		key = strconv.FormatFloat(v, 'f', -1, 64)
 	case float32:
-		key = strconv.FormatFloat(float64(v), 'f', -1, 64)
+		key = strconv.FormatFloat(float64(v), 'f', -1, 32)
 	case int:
 		key = strconv.Itoa(v)
 	case uint:
-		key = strconv.Itoa(int(v))
+		key = strconv.FormatUint(uint64(v), 10)
 	case int8:
 		key = strconv.Itoa(int(v))
 	case uint8:
-		key = strconv.Itoa(int(v))
+		key = strconv.FormatUint(uint64(v), 10)
 	case int16:
 		key = strconv.Itoa(int(v))
 	case uint16:
-		key = strconv.Itoa(int(v))
+		key = strconv.FormatUint(uint64(v), 10)
 	case int32:
 		key = strconv.Itoa(int(v))
 	case uint32:
-		key = strconv.Itoa(int(v))
+		key = strconv.FormatUint(uint64(v), 10)
 	case int64:
 		key = strconv.FormatInt(v, 10)
 	case uint64:
diff --git a/contrib/log/aliyun/aliyun_test.go b/contrib/log/aliyun/aliyun_test.go
index e8e2624f0..c4bfde480 100644
--- a/contrib/log/aliyun/aliyun_test.go
+++ b/contrib/log/aliyun/aliyun_test.go
@@ -2,6 +2,7 @@ package aliyun
 
 import (
 	"math"
+	"reflect"
 	"testing"
 
 	"github.com/go-kratos/kratos/v2/log"
@@ -99,34 +100,44 @@ func TestLog(t *testing.T) {
 	}
 }
 
+func TestNewString(t *testing.T) {
+	ptr := newString("")
+	if kind := reflect.TypeOf(ptr).Kind(); kind != reflect.Ptr {
+		t.Errorf("want type: %v, got type: %v", reflect.Ptr, kind)
+	}
+}
+
 func TestToString(t *testing.T) {
 	tests := []struct {
-		in  interface{}
-		out string
+		name string
+		in   interface{}
+		out  string
 	}{
-		{math.MaxFloat64, "17976931348623157000000000000000000000000000000000000" +
-			"000000000000000000000000000000000000000000000000000000000000000000000000000" +
-			"000000000000000000000000000000000000000000000000000000000000000000000000000" +
-			"000000000000000000000000000000000000000000000000000000000000000000000000000" +
-			"0000000000000000000000000000000"},
-		{math.MaxFloat32, "340282346638528860000000000000000000000"},
-		{1<<((32<<(^uint(0)>>63))-1) - 1, "9223372036854775807"},
-		{uint(1<<(32<<(^uint(0)>>63)) - 1), "-1"},
-		{math.MaxInt8, "127"},
-		{math.MaxUint8, "255"},
-		{math.MaxInt16, "32767"},
-		{math.MaxUint16, "65535"},
-		{math.MaxInt32, "2147483647"},
-		{math.MaxUint32, "4294967295"},
-		{math.MaxInt64, "9223372036854775807"},
-		{uint64(math.MaxUint64), "18446744073709551615"},
-		{"abc", "abc"},
-		{false, "false"},
-		{[]byte("abc"), "abc"},
+		{"float64", 6.66, "6.66"},
+		{"max float64", math.MaxFloat64, "179769313486231570000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000"}, //nolint:lll
+		{"float32", float32(6.66), "6.66"},
+		{"max float32", math.MaxFloat32, "340282346638528860000000000000000000000"},
+		{"int", int(math.MaxInt64), "9223372036854775807"},
+		{"uint", uint(math.MaxUint64), "18446744073709551615"},
+		{"int8", math.MaxInt8, "127"},
+		{"uint8", math.MaxUint8, "255"},
+		{"int16", math.MaxInt16, "32767"},
+		{"uint16", math.MaxUint16, "65535"},
+		{"int32", math.MaxInt32, "2147483647"},
+		{"uint32", math.MaxUint32, "4294967295"},
+		{"int64", math.MaxInt64, "9223372036854775807"},
+		{"uint64", uint64(math.MaxUint64), "18446744073709551615"},
+		{"string", "abc", "abc"},
+		{"bool", false, "false"},
+		{"[]byte", []byte("abc"), "abc"},
+		{"struct", struct{ Name string }{}, `{"Name":""}`},
 	}
 	for _, test := range tests {
-		if toString(test.in) != test.out {
-			t.Fatalf("want: %s, got: %s", test.out, toString(test.in))
-		}
+		t.Run(test.name, func(t *testing.T) {
+			out := toString(test.in)
+			if test.out != out {
+				t.Fatalf("want: %s, got: %s", test.out, out)
+			}
+		})
 	}
 }
diff --git a/contrib/log/aliyun/go.mod b/contrib/log/aliyun/go.mod
index 73edfb732..83029a5d4 100644
--- a/contrib/log/aliyun/go.mod
+++ b/contrib/log/aliyun/go.mod
@@ -4,7 +4,7 @@ go 1.16
 
 require (
 	github.com/aliyun/aliyun-log-go-sdk v0.1.37
-	github.com/go-kratos/kratos/v2 v2.5.1
+	github.com/go-kratos/kratos/v2 v2.5.2
 	google.golang.org/protobuf v1.28.1
 )
 
diff --git a/contrib/log/fluent/fluent_test.go b/contrib/log/fluent/fluent_test.go
index 5b7b3e171..41f7080d3 100644
--- a/contrib/log/fluent/fluent_test.go
+++ b/contrib/log/fluent/fluent_test.go
@@ -11,18 +11,23 @@ import (
 )
 
 func TestMain(m *testing.M) {
+	listener := func(ln net.Listener) {
+		conn, err := ln.Accept()
+		if err != nil {
+			return
+		}
+		defer conn.Close()
+		_, err = io.ReadAll(conn)
+		if err != nil {
+			return
+		}
+	}
+
 	if ln, err := net.Listen("tcp", ":24224"); err == nil {
 		defer ln.Close()
 		go func() {
 			for {
-				conn, err := ln.Accept()
-				if err != nil {
-					return
-				}
-				defer conn.Close()
-				if _, err = io.ReadAll(conn); err != nil {
-					continue
-				}
+				listener(ln)
 			}
 		}()
 	}
diff --git a/contrib/log/fluent/go.mod b/contrib/log/fluent/go.mod
index 8b3a4efcd..cd2e6ff99 100644
--- a/contrib/log/fluent/go.mod
+++ b/contrib/log/fluent/go.mod
@@ -5,7 +5,7 @@ go 1.16
 require (
 	github.com/bmizerany/assert v0.0.0-20160611221934-b7ed37b82869 // indirect
 	github.com/fluent/fluent-logger-golang v1.9.0
-	github.com/go-kratos/kratos/v2 v2.5.1
+	github.com/go-kratos/kratos/v2 v2.5.2
 	github.com/kr/pretty v0.3.0 // indirect
 	github.com/tinylib/msgp v1.1.6 // indirect
 )
diff --git a/contrib/log/logrus/go.mod b/contrib/log/logrus/go.mod
index 5d923e1cf..75465145e 100644
--- a/contrib/log/logrus/go.mod
+++ b/contrib/log/logrus/go.mod
@@ -3,7 +3,7 @@ module github.com/go-kratos/kratos/contrib/log/logrus/v2
 go 1.16
 
 require (
-	github.com/go-kratos/kratos/v2 v2.5.1
+	github.com/go-kratos/kratos/v2 v2.5.2
 	github.com/sirupsen/logrus v1.8.1
 )
 
diff --git a/contrib/log/tencent/go.mod b/contrib/log/tencent/go.mod
index d5a758f03..b102d7259 100644
--- a/contrib/log/tencent/go.mod
+++ b/contrib/log/tencent/go.mod
@@ -3,7 +3,7 @@ module github.com/go-kratos/kratos/contrib/log/tencent/v2
 go 1.16
 
 require (
-	github.com/go-kratos/kratos/v2 v2.5.1
+	github.com/go-kratos/kratos/v2 v2.5.2
 	github.com/tencentcloud/tencentcloud-cls-sdk-go v1.0.2
 	google.golang.org/protobuf v1.28.0
 )
diff --git a/contrib/log/tencent/tencent.go b/contrib/log/tencent/tencent.go
index 8becf7883..3016926e0 100644
--- a/contrib/log/tencent/tencent.go
+++ b/contrib/log/tencent/tencent.go
@@ -14,8 +14,8 @@ import (
 
 type Logger interface {
 	log.Logger
-	GetProducer() *cls.AsyncProducerClient
 
+	GetProducer() *cls.AsyncProducerClient
 	Close() error
 }
 
@@ -66,25 +66,20 @@ func WithAccessSecret(as string) Option {
 type Option func(cls *options)
 
 func (log *tencentLog) Close() error {
-	err := log.producer.Close(5000)
-	return err
+	return log.producer.Close(5000)
 }
 
 func (log *tencentLog) Log(level log.Level, keyvals ...interface{}) error {
-	buf := level.String()
-	levelTitle := "level"
-	contents := make([]*cls.Log_Content, 0)
+	contents := make([]*cls.Log_Content, 0, len(keyvals)/2+1)
 
 	contents = append(contents, &cls.Log_Content{
-		Key:   &levelTitle,
-		Value: &buf,
+		Key:   newString(level.Key()),
+		Value: newString(level.String()),
 	})
 	for i := 0; i < len(keyvals); i += 2 {
-		key := toString(keyvals[i])
-		value := toString(keyvals[i+1])
 		contents = append(contents, &cls.Log_Content{
-			Key:   &key,
-			Value: &value,
+			Key:   newString(toString(keyvals[i])),
+			Value: newString(toString(keyvals[i+1])),
 		})
 	}
 
@@ -92,8 +87,7 @@ func (log *tencentLog) Log(level log.Level, keyvals ...interface{}) error {
 		Time:     proto.Int64(time.Now().Unix()),
 		Contents: contents,
 	}
-	err := log.producer.SendLog(log.opts.topicID, logInst, nil)
-	return err
+	return log.producer.SendLog(log.opts.topicID, logInst, nil)
 }
 
 func NewLogger(options ...Option) (Logger, error) {
@@ -115,6 +109,10 @@ func NewLogger(options ...Option) (Logger, error) {
 	}, nil
 }
 
+func newString(s string) *string {
+	return &s
+}
+
 // toString convert any type to string
 func toString(v interface{}) string {
 	var key string
@@ -125,23 +123,23 @@ func toString(v interface{}) string {
 	case float64:
 		key = strconv.FormatFloat(v, 'f', -1, 64)
 	case float32:
-		key = strconv.FormatFloat(float64(v), 'f', -1, 64)
+		key = strconv.FormatFloat(float64(v), 'f', -1, 32)
 	case int:
 		key = strconv.Itoa(v)
 	case uint:
-		key = strconv.Itoa(int(v))
+		key = strconv.FormatUint(uint64(v), 10)
 	case int8:
 		key = strconv.Itoa(int(v))
 	case uint8:
-		key = strconv.Itoa(int(v))
+		key = strconv.FormatUint(uint64(v), 10)
 	case int16:
 		key = strconv.Itoa(int(v))
 	case uint16:
-		key = strconv.Itoa(int(v))
+		key = strconv.FormatUint(uint64(v), 10)
 	case int32:
 		key = strconv.Itoa(int(v))
 	case uint32:
-		key = strconv.Itoa(int(v))
+		key = strconv.FormatUint(uint64(v), 10)
 	case int64:
 		key = strconv.FormatInt(v, 10)
 	case uint64:
diff --git a/contrib/log/tencent/tencent_test.go b/contrib/log/tencent/tencent_test.go
index b37c1b22c..76bc13bdd 100644
--- a/contrib/log/tencent/tencent_test.go
+++ b/contrib/log/tencent/tencent_test.go
@@ -1,6 +1,8 @@
 package tencent
 
 import (
+	"math"
+	"reflect"
 	"testing"
 
 	"github.com/go-kratos/kratos/v2/log"
@@ -101,3 +103,45 @@ func TestLog(t *testing.T) {
 		t.Errorf("Log() returns error:%v", err)
 	}
 }
+
+func TestNewString(t *testing.T) {
+	ptr := newString("")
+	if kind := reflect.TypeOf(ptr).Kind(); kind != reflect.Ptr {
+		t.Errorf("want type: %v, got type: %v", reflect.Ptr, kind)
+	}
+}
+
+func TestToString(t *testing.T) {
+	tests := []struct {
+		name string
+		in   interface{}
+		out  string
+	}{
+		{"float64", 6.66, "6.66"},
+		{"max float64", math.MaxFloat64, "179769313486231570000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000"}, //nolint:lll
+		{"float32", float32(6.66), "6.66"},
+		{"max float32", math.MaxFloat32, "340282346638528860000000000000000000000"},
+		{"int", int(math.MaxInt64), "9223372036854775807"},
+		{"uint", uint(math.MaxUint64), "18446744073709551615"},
+		{"int8", math.MaxInt8, "127"},
+		{"uint8", math.MaxUint8, "255"},
+		{"int16", math.MaxInt16, "32767"},
+		{"uint16", math.MaxUint16, "65535"},
+		{"int32", math.MaxInt32, "2147483647"},
+		{"uint32", math.MaxUint32, "4294967295"},
+		{"int64", math.MaxInt64, "9223372036854775807"},
+		{"uint64", uint64(math.MaxUint64), "18446744073709551615"},
+		{"string", "abc", "abc"},
+		{"bool", false, "false"},
+		{"[]byte", []byte("abc"), "abc"},
+		{"struct", struct{ Name string }{}, `{"Name":""}`},
+	}
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			out := toString(test.in)
+			if test.out != out {
+				t.Fatalf("want: %s, got: %s", test.out, out)
+			}
+		})
+	}
+}
diff --git a/contrib/log/zap/go.mod b/contrib/log/zap/go.mod
index 8f8d5a9a8..ad54dd222 100644
--- a/contrib/log/zap/go.mod
+++ b/contrib/log/zap/go.mod
@@ -3,7 +3,7 @@ module github.com/go-kratos/kratos/contrib/log/zap/v2
 go 1.16
 
 require (
-	github.com/go-kratos/kratos/v2 v2.5.1
+	github.com/go-kratos/kratos/v2 v2.5.2
 	go.uber.org/zap v1.23.0
 )
 
diff --git a/contrib/metrics/datadog/go.mod b/contrib/metrics/datadog/go.mod
index 78f500398..42d434532 100644
--- a/contrib/metrics/datadog/go.mod
+++ b/contrib/metrics/datadog/go.mod
@@ -5,7 +5,7 @@ go 1.16
 require (
 	github.com/DataDog/datadog-go v4.8.3+incompatible
 	github.com/Microsoft/go-winio v0.5.2 // indirect
-	github.com/go-kratos/kratos/v2 v2.5.1
+	github.com/go-kratos/kratos/v2 v2.5.2
 )
 
 replace github.com/go-kratos/kratos/v2 => ../../../
diff --git a/contrib/metrics/prometheus/go.mod b/contrib/metrics/prometheus/go.mod
index 462f13f17..4a31ccadd 100644
--- a/contrib/metrics/prometheus/go.mod
+++ b/contrib/metrics/prometheus/go.mod
@@ -3,7 +3,7 @@ module github.com/go-kratos/kratos/contrib/metrics/prometheus/v2
 go 1.16
 
 require (
-	github.com/go-kratos/kratos/v2 v2.5.1
+	github.com/go-kratos/kratos/v2 v2.5.2
 	github.com/prometheus/client_golang v1.12.2
 	github.com/prometheus/common v0.37.0
 )
diff --git a/contrib/opensergo/go.mod b/contrib/opensergo/go.mod
index 1c96a2713..683f7850d 100644
--- a/contrib/opensergo/go.mod
+++ b/contrib/opensergo/go.mod
@@ -3,7 +3,7 @@ module github.com/go-kratos/kratos/contrib/opensergo/v2
 go 1.17
 
 require (
-	github.com/go-kratos/kratos/v2 v2.5.1
+	github.com/go-kratos/kratos/v2 v2.5.2
 	github.com/opensergo/opensergo-go v0.0.0-20220331070310-e5b01fee4d1c
 	golang.org/x/net v0.0.0-20220520000938-2e3eb7b945c2
 	google.golang.org/genproto v0.0.0-20220519153652-3a47de7e79bd
diff --git a/contrib/opensergo/opensergo.go b/contrib/opensergo/opensergo.go
index 112c0babe..e8f38c7bf 100644
--- a/contrib/opensergo/opensergo.go
+++ b/contrib/opensergo/opensergo.go
@@ -3,6 +3,7 @@ package opensergo
 import (
 	"encoding/json"
 	"net"
+	"net/http"
 	"net/url"
 	"os"
 	"strconv"
@@ -186,15 +187,15 @@ func listDescriptors() (services []*v1.ServiceDescriptor, types []*v1.TypeDescri
 func HTTPPatternInfo(pattern interface{}) (method string, path string) {
 	switch p := pattern.(type) {
 	case *annotations.HttpRule_Get:
-		return "GET", p.Get
+		return http.MethodGet, p.Get
 	case *annotations.HttpRule_Post:
-		return "POST", p.Post
+		return http.MethodPost, p.Post
 	case *annotations.HttpRule_Delete:
-		return "DELETE", p.Delete
+		return http.MethodDelete, p.Delete
 	case *annotations.HttpRule_Patch:
-		return "PATCH", p.Patch
+		return http.MethodPatch, p.Patch
 	case *annotations.HttpRule_Put:
-		return "PUT", p.Put
+		return http.MethodPut, p.Put
 	case *annotations.HttpRule_Custom:
 		return p.Custom.Kind, p.Custom.Path
 	default:
diff --git a/contrib/opensergo/opensergo_test.go b/contrib/opensergo/opensergo_test.go
index b63430e20..70ffef8fc 100644
--- a/contrib/opensergo/opensergo_test.go
+++ b/contrib/opensergo/opensergo_test.go
@@ -2,6 +2,7 @@ package opensergo
 
 import (
 	"net"
+	"net/http"
 	"os"
 	"path/filepath"
 	"reflect"
@@ -195,7 +196,7 @@ func TestHTTPPatternInfo(t *testing.T) {
 			args: args{
 				pattern: &annotations.HttpRule_Get{Get: "/foo"},
 			},
-			wantMethod: "GET",
+			wantMethod: http.MethodGet,
 			wantPath:   "/foo",
 		},
 		{
@@ -203,7 +204,7 @@ func TestHTTPPatternInfo(t *testing.T) {
 			args: args{
 				pattern: &annotations.HttpRule_Post{Post: "/foo"},
 			},
-			wantMethod: "POST",
+			wantMethod: http.MethodPost,
 			wantPath:   "/foo",
 		},
 		{
@@ -211,7 +212,7 @@ func TestHTTPPatternInfo(t *testing.T) {
 			args: args{
 				pattern: &annotations.HttpRule_Put{Put: "/foo"},
 			},
-			wantMethod: "PUT",
+			wantMethod: http.MethodPut,
 			wantPath:   "/foo",
 		},
 		{
@@ -219,7 +220,7 @@ func TestHTTPPatternInfo(t *testing.T) {
 			args: args{
 				pattern: &annotations.HttpRule_Delete{Delete: "/foo"},
 			},
-			wantMethod: "DELETE",
+			wantMethod: http.MethodDelete,
 			wantPath:   "/foo",
 		},
 		{
@@ -227,7 +228,7 @@ func TestHTTPPatternInfo(t *testing.T) {
 			args: args{
 				pattern: &annotations.HttpRule_Patch{Patch: "/foo"},
 			},
-			wantMethod: "PATCH",
+			wantMethod: http.MethodPatch,
 			wantPath:   "/foo",
 		},
 		{
diff --git a/contrib/registry/consul/go.mod b/contrib/registry/consul/go.mod
index e78723c70..db17f9cc5 100644
--- a/contrib/registry/consul/go.mod
+++ b/contrib/registry/consul/go.mod
@@ -3,7 +3,7 @@ module github.com/go-kratos/kratos/contrib/registry/consul/v2
 go 1.16
 
 require (
-	github.com/go-kratos/kratos/v2 v2.5.1
+	github.com/go-kratos/kratos/v2 v2.5.2
 	github.com/hashicorp/consul/api v1.14.0
 )
 
diff --git a/contrib/registry/consul/registry.go b/contrib/registry/consul/registry.go
index d1c47d774..b2f2a3fe7 100644
--- a/contrib/registry/consul/registry.go
+++ b/contrib/registry/consul/registry.go
@@ -7,14 +7,14 @@ import (
 	"sync/atomic"
 	"time"
 
-	"github.com/go-kratos/kratos/v2/registry"
-
 	"github.com/hashicorp/consul/api"
+
+	"github.com/go-kratos/kratos/v2/registry"
 )
 
 var (
-	_ registry.Registrar = &Registry{}
-	_ registry.Discovery = &Registry{}
+	_ registry.Registrar = (*Registry)(nil)
+	_ registry.Discovery = (*Registry)(nil)
 )
 
 // Option is consul registry option.
diff --git a/contrib/registry/discovery/go.mod b/contrib/registry/discovery/go.mod
index 40b61cb01..55728f7c3 100644
--- a/contrib/registry/discovery/go.mod
+++ b/contrib/registry/discovery/go.mod
@@ -3,7 +3,7 @@ module github.com/go-kratos/kratos/contrib/registry/discovery/v2
 go 1.16
 
 require (
-	github.com/go-kratos/kratos/v2 v2.5.1
+	github.com/go-kratos/kratos/v2 v2.5.2
 	github.com/go-resty/resty/v2 v2.7.0
 	github.com/pkg/errors v0.9.1
 )
diff --git a/contrib/registry/etcd/go.mod b/contrib/registry/etcd/go.mod
index 1976385e1..c4c072ecb 100644
--- a/contrib/registry/etcd/go.mod
+++ b/contrib/registry/etcd/go.mod
@@ -3,7 +3,7 @@ module github.com/go-kratos/kratos/contrib/registry/etcd/v2
 go 1.16
 
 require (
-	github.com/go-kratos/kratos/v2 v2.5.1
+	github.com/go-kratos/kratos/v2 v2.5.2
 	go.etcd.io/etcd/client/v3 v3.5.4
 	google.golang.org/grpc v1.46.2
 )
diff --git a/contrib/registry/etcd/registry.go b/contrib/registry/etcd/registry.go
index 5592f62d2..ca858c993 100644
--- a/contrib/registry/etcd/registry.go
+++ b/contrib/registry/etcd/registry.go
@@ -12,8 +12,8 @@ import (
 )
 
 var (
-	_ registry.Registrar = &Registry{}
-	_ registry.Discovery = &Registry{}
+	_ registry.Registrar = (*Registry)(nil)
+	_ registry.Discovery = (*Registry)(nil)
 )
 
 // Option is etcd registry option.
diff --git a/contrib/registry/eureka/client.go b/contrib/registry/eureka/client.go
index f2b4e96f3..ab9eb30d2 100644
--- a/contrib/registry/eureka/client.go
+++ b/contrib/registry/eureka/client.go
@@ -14,14 +14,14 @@ import (
 )
 
 const (
-	statusUp            = "UP"
-	statusDown          = "DOWN"
-	statusOutOfServeice = "OUT_OF_SERVICE"
-	heartbeatRetry      = 3
-	maxIdleConns        = 100
-	heartbeatTime       = 10
-	httpTimeout         = 3
-	refreshTime         = 30
+	statusUp           = "UP"
+	statusDown         = "DOWN"
+	statusOutOfService = "OUT_OF_SERVICE"
+	heartbeatRetry     = 3
+	maxIdleConns       = 100
+	heartbeatTime      = 10
+	httpTimeout        = 3
+	refreshTime        = 30
 )
 
 type Endpoint struct {
@@ -153,7 +153,7 @@ func NewClient(urls []string, opts ...ClientOption) *Client {
 
 func (e *Client) FetchApps(ctx context.Context) []Application {
 	var m ApplicationsRootResponse
-	if err := e.do(ctx, "GET", []string{"apps"}, nil, &m); err != nil {
+	if err := e.do(ctx, http.MethodGet, []string{"apps"}, nil, &m); err != nil {
 		return nil
 	}
 
@@ -161,7 +161,7 @@ func (e *Client) FetchApps(ctx context.Context) []Application {
 }
 
 func (e *Client) FetchAppInstances(ctx context.Context, appID string) (m Application, err error) {
-	err = e.do(ctx, "GET", []string{"apps", appID}, nil, &m)
+	err = e.do(ctx, http.MethodGet, []string{"apps", appID}, nil, &m)
 	return
 }
 
@@ -174,21 +174,21 @@ func (e *Client) FetchAppUpInstances(ctx context.Context, appID string) []Instan
 }
 
 func (e *Client) FetchAppInstance(ctx context.Context, appID string, instanceID string) (m Instance, err error) {
-	err = e.do(ctx, "GET", []string{"apps", appID, instanceID}, nil, &m)
+	err = e.do(ctx, http.MethodGet, []string{"apps", appID, instanceID}, nil, &m)
 	return
 }
 
 func (e *Client) FetchInstance(ctx context.Context, instanceID string) (m Instance, err error) {
-	err = e.do(ctx, "GET", []string{"instances", instanceID}, nil, &m)
+	err = e.do(ctx, http.MethodGet, []string{"instances", instanceID}, nil, &m)
 	return
 }
 
 func (e *Client) Out(ctx context.Context, appID, instanceID string) error {
-	return e.do(ctx, "PUT", []string{"apps", appID, instanceID, fmt.Sprintf("status?value=%s", statusOutOfServeice)}, nil, nil)
+	return e.do(ctx, http.MethodPut, []string{"apps", appID, instanceID, fmt.Sprintf("status?value=%s", statusOutOfService)}, nil, nil)
 }
 
 func (e *Client) Down(ctx context.Context, appID, instanceID string) error {
-	return e.do(ctx, "PUT", []string{"apps", appID, instanceID, fmt.Sprintf("status?value=%s", statusDown)}, nil, nil)
+	return e.do(ctx, http.MethodPut, []string{"apps", appID, instanceID, fmt.Sprintf("status?value=%s", statusDown)}, nil, nil)
 }
 
 func (e *Client) FetchAllUpInstances(ctx context.Context) []Instance {
@@ -200,7 +200,7 @@ func (e *Client) Register(ctx context.Context, ep Endpoint) error {
 }
 
 func (e *Client) Deregister(ctx context.Context, appID, instanceID string) error {
-	if err := e.do(ctx, "DELETE", []string{"apps", appID, instanceID}, nil, nil); err != nil {
+	if err := e.do(ctx, http.MethodDelete, []string{"apps", appID, instanceID}, nil, nil); err != nil {
 		return err
 	}
 	go e.cancelHeartbeat(appID)
@@ -239,7 +239,7 @@ func (e *Client) registerEndpoint(ctx context.Context, ep Endpoint) error {
 	if err != nil {
 		return err
 	}
-	return e.do(ctx, "POST", []string{"apps", ep.AppID}, bytes.NewReader(body), nil)
+	return e.do(ctx, http.MethodPost, []string{"apps", ep.AppID}, bytes.NewReader(body), nil)
 }
 
 func (e *Client) Heartbeat(ep Endpoint) {
@@ -257,7 +257,7 @@ func (e *Client) Heartbeat(ep Endpoint) {
 		case <-e.keepalive[ep.AppID]:
 			return
 		case <-ticker.C:
-			if err := e.do(e.ctx, "PUT", []string{"apps", ep.AppID, ep.InstanceID}, nil, nil); err != nil {
+			if err := e.do(e.ctx, http.MethodPut, []string{"apps", ep.AppID, ep.InstanceID}, nil, nil); err != nil {
 				if retryCount++; retryCount > heartbeatRetry {
 					_ = e.registerEndpoint(e.ctx, ep)
 					retryCount = 0
@@ -268,8 +268,8 @@ func (e *Client) Heartbeat(ep Endpoint) {
 }
 
 func (e *Client) cancelHeartbeat(appID string) {
-	defer e.lock.Unlock()
 	e.lock.Lock()
+	defer e.lock.Unlock()
 	if ch, ok := e.keepalive[appID]; ok {
 		ch <- struct{}{}
 	}
@@ -307,39 +307,50 @@ func (e *Client) buildAPI(currentTimes int, params ...string) string {
 	return strings.Join(params, "/")
 }
 
-func (e *Client) do(ctx context.Context, method string, params []string, input io.Reader, output interface{}) error {
-	for i := 0; i < e.maxRetry; i++ {
-		request, err := http.NewRequest(method, e.buildAPI(i, params...), input)
+func (e *Client) request(ctx context.Context, method string, params []string, input io.Reader, output interface{}, i int) (bool, error) {
+	request, err := http.NewRequestWithContext(ctx, method, e.buildAPI(i, params...), input)
+	if err != nil {
+		return false, err
+	}
+	request.Header.Add("User-Agent", "go-eureka-client")
+	request.Header.Add("Accept", "application/json;charset=UTF-8")
+	request.Header.Add("Content-Type", "application/json;charset=UTF-8")
+	resp, err := e.client.Do(request)
+	if err != nil {
+		return true, err
+	}
+	defer func() {
+		_, _ = io.Copy(io.Discard, resp.Body)
+		_ = resp.Body.Close()
+	}()
+
+	if output != nil && resp.StatusCode/100 == 2 {
+		data, err := io.ReadAll(resp.Body)
 		if err != nil {
-			return err
+			return false, err
 		}
-		request = request.WithContext(ctx)
-		request.Header.Add("User-Agent", "go-eureka-client")
-		request.Header.Add("Accept", "application/json;charset=UTF-8")
-		request.Header.Add("Content-Type", "application/json;charset=UTF-8")
-		resp, err := e.client.Do(request)
+		err = json.Unmarshal(data, output)
 		if err != nil {
-			continue
-		}
-		defer func() {
-			_, _ = io.Copy(io.Discard, resp.Body)
-			resp.Body.Close()
-		}()
-
-		if output != nil && resp.StatusCode/100 == 2 {
-			data, err := io.ReadAll(resp.Body)
-			if err != nil {
-				return err
-			}
-			if err = json.Unmarshal(data, output); err != nil {
-				return err
-			}
+			return false, err
 		}
+	}
 
-		if resp.StatusCode >= http.StatusBadRequest {
-			return fmt.Errorf("response Error %d", resp.StatusCode)
-		}
+	if resp.StatusCode >= http.StatusBadRequest {
+		return false, fmt.Errorf("response Error %d", resp.StatusCode)
+	}
 
+	return false, nil
+}
+
+func (e *Client) do(ctx context.Context, method string, params []string, input io.Reader, output interface{}) error {
+	for i := 0; i < e.maxRetry; i++ {
+		retry, err := e.request(ctx, method, params, input, output, i)
+		if retry {
+			continue
+		}
+		if err != nil {
+			return err
+		}
 		return nil
 	}
 	return fmt.Errorf("retry after %d times", e.maxRetry)
diff --git a/contrib/registry/eureka/register.go b/contrib/registry/eureka/register.go
index 9588df641..242ec9105 100644
--- a/contrib/registry/eureka/register.go
+++ b/contrib/registry/eureka/register.go
@@ -11,8 +11,8 @@ import (
 )
 
 var (
-	_ registry.Registrar = &Registry{}
-	_ registry.Discovery = &Registry{}
+	_ registry.Registrar = (*Registry)(nil)
+	_ registry.Discovery = (*Registry)(nil)
 )
 
 type Option func(o *Registry)
diff --git a/contrib/registry/kubernetes/go.mod b/contrib/registry/kubernetes/go.mod
index 3f20affb1..21517f5fb 100644
--- a/contrib/registry/kubernetes/go.mod
+++ b/contrib/registry/kubernetes/go.mod
@@ -3,7 +3,7 @@ module github.com/go-kratos/kratos/contrib/registry/kubernetes/v2
 go 1.16
 
 require (
-	github.com/go-kratos/kratos/v2 v2.5.1
+	github.com/go-kratos/kratos/v2 v2.5.2
 	github.com/json-iterator/go v1.1.12
 	k8s.io/api v0.24.3
 	k8s.io/apimachinery v0.24.3
diff --git a/contrib/registry/nacos/go.mod b/contrib/registry/nacos/go.mod
index d6048dfc0..75f673346 100644
--- a/contrib/registry/nacos/go.mod
+++ b/contrib/registry/nacos/go.mod
@@ -3,7 +3,7 @@ module github.com/go-kratos/kratos/contrib/registry/nacos/v2
 go 1.16
 
 require (
-	github.com/go-kratos/kratos/v2 v2.5.1
+	github.com/go-kratos/kratos/v2 v2.5.2
 	github.com/nacos-group/nacos-sdk-go v1.0.9
 )
 
diff --git a/contrib/registry/polaris/go.mod b/contrib/registry/polaris/go.mod
index 306fe9275..f70157cca 100644
--- a/contrib/registry/polaris/go.mod
+++ b/contrib/registry/polaris/go.mod
@@ -3,7 +3,7 @@ module github.com/go-kratos/kratos/contrib/registry/polaris/v2
 go 1.16
 
 require (
-	github.com/go-kratos/kratos/v2 v2.5.1
+	github.com/go-kratos/kratos/v2 v2.5.2
 	github.com/polarismesh/polaris-go v1.1.0
 )
 
diff --git a/contrib/registry/zookeeper/go.mod b/contrib/registry/zookeeper/go.mod
index 09c35a1b9..719a78de0 100644
--- a/contrib/registry/zookeeper/go.mod
+++ b/contrib/registry/zookeeper/go.mod
@@ -3,7 +3,7 @@ module github.com/go-kratos/kratos/contrib/registry/zookeeper/v2
 go 1.16
 
 require (
-	github.com/go-kratos/kratos/v2 v2.5.1
+	github.com/go-kratos/kratos/v2 v2.5.2
 	github.com/go-zookeeper/zk v1.0.3
 	golang.org/x/sync v0.0.0-20220513210516-0976fa681c29
 )
diff --git a/contrib/registry/zookeeper/register.go b/contrib/registry/zookeeper/register.go
index 771a5bbc4..8f21745d1 100644
--- a/contrib/registry/zookeeper/register.go
+++ b/contrib/registry/zookeeper/register.go
@@ -12,8 +12,8 @@ import (
 )
 
 var (
-	_ registry.Registrar = &Registry{}
-	_ registry.Discovery = &Registry{}
+	_ registry.Registrar = (*Registry)(nil)
+	_ registry.Discovery = (*Registry)(nil)
 )
 
 // Option is etcd registry option.
diff --git a/log/level.go b/log/level.go
index 22f41c787..1a9664236 100644
--- a/log/level.go
+++ b/log/level.go
@@ -21,6 +21,10 @@ const (
 	LevelFatal
 )
 
+func (l Level) Key() string {
+	return LevelKey
+}
+
 func (l Level) String() string {
 	switch l {
 	case LevelDebug:
diff --git a/log/level_test.go b/log/level_test.go
index d36882912..193503c68 100644
--- a/log/level_test.go
+++ b/log/level_test.go
@@ -2,6 +2,12 @@ package log
 
 import "testing"
 
+func TestLevel_Key(t *testing.T) {
+	if LevelInfo.Key() != LevelKey {
+		t.Errorf("want: %s, got: %s", LevelKey, LevelInfo.Key())
+	}
+}
+
 func TestLevel_String(t *testing.T) {
 	tests := []struct {
 		name string
diff --git a/middleware/auth/jwt/jwt_test.go b/middleware/auth/jwt/jwt_test.go
index 188744b01..711757bcf 100644
--- a/middleware/auth/jwt/jwt_test.go
+++ b/middleware/auth/jwt/jwt_test.go
@@ -254,7 +254,7 @@ func TestServer(t *testing.T) {
 			}
 			if test.exceptErr == nil {
 				if testToken == nil {
-					t.Errorf("except testToken not nil, but got nil")
+					t.Fatal("except testToken not nil, but got nil")
 				}
 				_, ok := testToken.(jwt.MapClaims)
 				if !ok {
@@ -493,3 +493,26 @@ func TestClientMissKey(t *testing.T) {
 		}
 	})
 }
+
+func TestNewContextAndFromContext(t *testing.T) {
+	tests := []struct {
+		name   string
+		claims jwt.MapClaims
+	}{
+		{"val not nil", jwt.MapClaims{"name": "kratos"}},
+		{"val nil", nil},
+	}
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			ctx := NewContext(context.Background(), test.claims)
+
+			claims, ok := FromContext(ctx)
+			if !ok {
+				t.Fatal("ctx not found authKey{}")
+			}
+			if !reflect.DeepEqual(test.claims, claims) {
+				t.Errorf(`want: %s, got: %v`, test.claims, claims)
+			}
+		})
+	}
+}
diff --git a/middleware/logging/logging_test.go b/middleware/logging/logging_test.go
index 6ad1a02c9..431d89014 100644
--- a/middleware/logging/logging_test.go
+++ b/middleware/logging/logging_test.go
@@ -111,7 +111,7 @@ func (d *dummyStringer) String() string {
 	return "my value"
 }
 
-func Test_extractArgs(t *testing.T) {
+func TestExtractArgs(t *testing.T) {
 	if extractArgs(&dummyStringer{field: ""}) != "my value" {
 		t.Errorf(`The stringified dummyStringer structure must be equal to "my value", %v given`, extractArgs(&dummyStringer{field: ""}))
 	}
@@ -120,3 +120,30 @@ func Test_extractArgs(t *testing.T) {
 		t.Errorf(`The stringified dummy structure must be equal to "&{field:value}", %v given`, extractArgs(&dummy{field: "value"}))
 	}
 }
+
+func TestExtractError(t *testing.T) {
+	tests := []struct {
+		name       string
+		err        error
+		wantLevel  log.Level
+		wantErrStr string
+	}{
+		{
+			"no error", nil, log.LevelInfo, "",
+		},
+		{
+			"error", errors.New("test error"), log.LevelError, "test error",
+		},
+	}
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			level, errStr := extractError(test.err)
+			if level != test.wantLevel {
+				t.Errorf("want: %d, got: %d", test.wantLevel, level)
+			}
+			if errStr != test.wantErrStr {
+				t.Errorf("want: %s, got: %s", test.wantErrStr, errStr)
+			}
+		})
+	}
+}
diff --git a/middleware/metadata/metadata.go b/middleware/metadata/metadata.go
index 5c29189f9..da9e43a96 100644
--- a/middleware/metadata/metadata.go
+++ b/middleware/metadata/metadata.go
@@ -51,16 +51,19 @@ func Server(opts ...Option) middleware.Middleware {
 	}
 	return func(handler middleware.Handler) middleware.Handler {
 		return func(ctx context.Context, req interface{}) (reply interface{}, err error) {
-			if tr, ok := transport.FromServerContext(ctx); ok {
-				md := options.md.Clone()
-				header := tr.RequestHeader()
-				for _, k := range header.Keys() {
-					if options.hasPrefix(k) {
-						md.Set(k, header.Get(k))
-					}
+			tr, ok := transport.FromServerContext(ctx)
+			if !ok {
+				return handler(ctx, req)
+			}
+
+			md := options.md.Clone()
+			header := tr.RequestHeader()
+			for _, k := range header.Keys() {
+				if options.hasPrefix(k) {
+					md.Set(k, header.Get(k))
 				}
-				ctx = metadata.NewServerContext(ctx, md)
 			}
+			ctx = metadata.NewServerContext(ctx, md)
 			return handler(ctx, req)
 		}
 	}
@@ -76,25 +79,28 @@ func Client(opts ...Option) middleware.Middleware {
 	}
 	return func(handler middleware.Handler) middleware.Handler {
 		return func(ctx context.Context, req interface{}) (reply interface{}, err error) {
-			if tr, ok := transport.FromClientContext(ctx); ok {
-				header := tr.RequestHeader()
-				// x-md-local-
-				for k, v := range options.md {
+			tr, ok := transport.FromClientContext(ctx)
+			if !ok {
+				return handler(ctx, req)
+			}
+
+			header := tr.RequestHeader()
+			// x-md-local-
+			for k, v := range options.md {
+				header.Set(k, v)
+			}
+			if md, ok := metadata.FromClientContext(ctx); ok {
+				for k, v := range md {
 					header.Set(k, v)
 				}
-				if md, ok := metadata.FromClientContext(ctx); ok {
-					for k, v := range md {
+			}
+			// x-md-global-
+			if md, ok := metadata.FromServerContext(ctx); ok {
+				for k, v := range md {
+					if options.hasPrefix(k) {
 						header.Set(k, v)
 					}
 				}
-				// x-md-global-
-				if md, ok := metadata.FromServerContext(ctx); ok {
-					for k, v := range md {
-						if options.hasPrefix(k) {
-							header.Set(k, v)
-						}
-					}
-				}
 			}
 			return handler(ctx, req)
 		}
diff --git a/middleware/metadata/metadata_test.go b/middleware/metadata/metadata_test.go
index e46a94f50..b083f9c10 100644
--- a/middleware/metadata/metadata_test.go
+++ b/middleware/metadata/metadata_test.go
@@ -4,6 +4,7 @@ import (
 	"context"
 	"errors"
 	"net/http"
+	"reflect"
 	"testing"
 
 	"github.com/go-kratos/kratos/v2/metadata"
@@ -33,15 +34,18 @@ func (tr *testTransport) Operation() string               { return "" }
 func (tr *testTransport) RequestHeader() transport.Header { return tr.header }
 func (tr *testTransport) ReplyHeader() transport.Header   { return tr.header }
 
+var (
+	globalKey   = "x-md-global-key"
+	globalValue = "global-value"
+	localKey    = "x-md-local-key"
+	localValue  = "local-value"
+	customKey   = "x-md-local-custom"
+	customValue = "custom-value"
+	constKey    = "x-md-local-const"
+	constValue  = "x-md-local-const"
+)
+
 func TestSever(t *testing.T) {
-	var (
-		globalKey   = "x-md-global-key"
-		globalValue = "global-value"
-		localKey    = "x-md-local-key"
-		localValue  = "local-value"
-		constKey    = "x-md-local-const"
-		constValue  = "x-md-local-const"
-	)
 	hs := func(ctx context.Context, in interface{}) (interface{}, error) {
 		md, ok := metadata.FromServerContext(ctx)
 		if !ok {
@@ -75,16 +79,6 @@ func TestSever(t *testing.T) {
 }
 
 func TestClient(t *testing.T) {
-	var (
-		globalKey   = "x-md-global-key"
-		globalValue = "global-value"
-		localKey    = "x-md-local-key"
-		localValue  = "local-value"
-		customKey   = "x-md-local-custom"
-		customValue = "custom-value"
-		constKey    = "x-md-local-const"
-		constValue  = "x-md-local-const"
-	)
 	hs := func(ctx context.Context, in interface{}) (interface{}, error) {
 		tr, ok := transport.FromClientContext(ctx)
 		if !ok {
@@ -127,13 +121,52 @@ func TestClient(t *testing.T) {
 	}
 }
 
-func Test_WithPropagatedPrefix(t *testing.T) {
-	o := &options{
+func TestWithConstants(t *testing.T) {
+	md := metadata.Metadata{
+		constKey: constValue,
+	}
+	options := &options{
+		md: metadata.Metadata{
+			"override": "override",
+		},
+	}
+
+	WithConstants(md)(options)
+	if !reflect.DeepEqual(md, options.md) {
+		t.Errorf("want: %v, got: %v", md, options.md)
+	}
+}
+
+func TestOptions_WithPropagatedPrefix(t *testing.T) {
+	options := &options{
 		prefix: []string{"override"},
 	}
-	WithPropagatedPrefix("something", "another")(o)
+	prefixes := []string{"something", "another"}
 
-	if len(o.prefix) != 2 {
+	WithPropagatedPrefix(prefixes...)(options)
+	if !reflect.DeepEqual(prefixes, options.prefix) {
 		t.Error("The prefix must be overridden.")
 	}
 }
+
+func TestOptions_hasPrefix(t *testing.T) {
+	tests := []struct {
+		name    string
+		options *options
+		key     string
+		exists  bool
+	}{
+		{"exists key upper", &options{prefix: []string{"prefix"}}, "PREFIX_true", true},
+		{"exists key lower", &options{prefix: []string{"prefix"}}, "prefix_true", true},
+		{"not exists key upper", &options{prefix: []string{"prefix"}}, "false_PREFIX", false},
+		{"not exists key lower", &options{prefix: []string{"prefix"}}, "false_prefix", false},
+	}
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			exists := test.options.hasPrefix(test.key)
+			if test.exists != exists {
+				t.Errorf("key: '%sr', not exists prefixs: %v", test.key, test.options.prefix)
+			}
+		})
+	}
+}
diff --git a/selector/node/ewma/node.go b/selector/node/ewma/node.go
index 4fed4aaa2..3b8d2a02c 100644
--- a/selector/node/ewma/node.go
+++ b/selector/node/ewma/node.go
@@ -4,6 +4,7 @@ import (
 	"container/list"
 	"context"
 	"math"
+	"net"
 	"sync"
 	"sync/atomic"
 	"time"
@@ -158,8 +159,9 @@ func (n *Node) Pick() selector.DoneFunc {
 			if n.errHandler != nil && n.errHandler(di.Err) {
 				success = 0
 			}
+			var netErr net.Error
 			if errors.Is(context.DeadlineExceeded, di.Err) || errors.Is(context.Canceled, di.Err) ||
-				errors.IsServiceUnavailable(di.Err) || errors.IsGatewayTimeout(di.Err) {
+				errors.IsServiceUnavailable(di.Err) || errors.IsGatewayTimeout(di.Err) || errors.As(di.Err, &netErr) {
 				success = 0
 			}
 		}
diff --git a/selector/node/ewma/node_test.go b/selector/node/ewma/node_test.go
index feac09f28..d930495c3 100644
--- a/selector/node/ewma/node_test.go
+++ b/selector/node/ewma/node_test.go
@@ -2,6 +2,7 @@ package ewma
 
 import (
 	"context"
+	"net"
 	"reflect"
 	"testing"
 	"time"
@@ -100,11 +101,15 @@ func TestDirectErrorHandler(t *testing.T) {
 			Endpoints: []string{"http://127.0.0.1:9090"},
 			Metadata:  map[string]string{"weight": "10"},
 		}))
-
+	errs := []error{
+		context.DeadlineExceeded,
+		context.Canceled,
+		net.ErrClosed,
+	}
 	for i := 0; i < 5; i++ {
 		var err error
 		if i != 0 {
-			err = context.DeadlineExceeded
+			err = errs[i%len(errs)]
 		}
 		done := wn.Pick()
 		if done == nil {
diff --git a/transport/grpc/balancer.go b/transport/grpc/balancer.go
index 948b736bb..f42dc23bd 100644
--- a/transport/grpc/balancer.go
+++ b/transport/grpc/balancer.go
@@ -1,13 +1,13 @@
 package grpc
 
 import (
-	"github.com/go-kratos/kratos/v2/registry"
-	"github.com/go-kratos/kratos/v2/selector"
-	"github.com/go-kratos/kratos/v2/transport"
-
 	"google.golang.org/grpc/balancer"
 	"google.golang.org/grpc/balancer/base"
 	"google.golang.org/grpc/metadata"
+
+	"github.com/go-kratos/kratos/v2/registry"
+	"github.com/go-kratos/kratos/v2/selector"
+	"github.com/go-kratos/kratos/v2/transport"
 )
 
 const (
@@ -15,8 +15,8 @@ const (
 )
 
 var (
-	_ base.PickerBuilder = &balancerBuilder{}
-	_ balancer.Picker    = &balancerPicker{}
+	_ base.PickerBuilder = (*balancerBuilder)(nil)
+	_ balancer.Picker    = (*balancerPicker)(nil)
 )
 
 func init() {
diff --git a/transport/http/binding/bind_test.go b/transport/http/binding/bind_test.go
index 20aadba7f..6cd8b6d5a 100644
--- a/transport/http/binding/bind_test.go
+++ b/transport/http/binding/bind_test.go
@@ -96,7 +96,7 @@ func TestBindForm(t *testing.T) {
 		{
 			name: "error not nil",
 			args: args{
-				req:    &http.Request{Method: "POST"},
+				req:    &http.Request{Method: http.MethodPost},
 				target: &p1,
 			},
 			wantErr: true,
@@ -106,7 +106,7 @@ func TestBindForm(t *testing.T) {
 			name: "error is nil",
 			args: args{
 				req: &http.Request{
-					Method: "POST",
+					Method: http.MethodPost,
 					Header: http.Header{"Content-Type": {"application/x-www-form-urlencoded; param=value"}},
 					Body:   io.NopCloser(strings.NewReader("name=kratos&url=https://go-kratos.dev/")),
 				},
@@ -119,7 +119,7 @@ func TestBindForm(t *testing.T) {
 			name: "error BadRequest",
 			args: args{
 				req: &http.Request{
-					Method: "POST",
+					Method: http.MethodPost,
 					Header: http.Header{"Content-Type": {"application/x-www-form-urlencoded; param=value"}},
 					Body:   io.NopCloser(strings.NewReader("age=a")),
 				},
diff --git a/transport/http/client_test.go b/transport/http/client_test.go
index ab8031dd5..9a0dd7829 100644
--- a/transport/http/client_test.go
+++ b/transport/http/client_test.go
@@ -9,6 +9,7 @@ import (
 	"fmt"
 	"io"
 	"log"
+	"net/http"
 	nethttp "net/http"
 	"reflect"
 	"strconv"
@@ -348,18 +349,18 @@ func TestNewClient(t *testing.T) {
 		t.Error(err)
 	}
 
-	err = client.Invoke(context.Background(), "POST", "/go", map[string]string{"name": "kratos"}, nil, EmptyCallOption{}, &mockCallOption{})
+	err = client.Invoke(context.Background(), http.MethodPost, "/go", map[string]string{"name": "kratos"}, nil, EmptyCallOption{}, &mockCallOption{})
 	if err == nil {
 		t.Error("err should not be equal to nil")
 	}
-	err = client.Invoke(context.Background(), "POST", "/go", map[string]string{"name": "kratos"}, nil, EmptyCallOption{}, &mockCallOption{needErr: true})
+	err = client.Invoke(context.Background(), http.MethodPost, "/go", map[string]string{"name": "kratos"}, nil, EmptyCallOption{}, &mockCallOption{needErr: true})
 	if err == nil {
 		t.Error("err should be equal to callOption err")
 	}
 	client.opts.encoder = func(ctx context.Context, contentType string, in interface{}) (body []byte, err error) {
 		return nil, errors.New("mock test encoder error")
 	}
-	err = client.Invoke(context.Background(), "POST", "/go", map[string]string{"name": "kratos"}, nil, EmptyCallOption{})
+	err = client.Invoke(context.Background(), http.MethodPost, "/go", map[string]string{"name": "kratos"}, nil, EmptyCallOption{})
 	if err == nil {
 		t.Error("err should be equal to encoder error")
 	}
diff --git a/transport/http/context_test.go b/transport/http/context_test.go
index daccccd95..6cae1b9ad 100644
--- a/transport/http/context_test.go
+++ b/transport/http/context_test.go
@@ -30,7 +30,7 @@ func TestContextHeader(t *testing.T) {
 func TestContextForm(t *testing.T) {
 	w := wrapper{
 		router: testRouter,
-		req:    &http.Request{Header: map[string][]string{"name": {"kratos"}}, Method: "POST"},
+		req:    &http.Request{Header: map[string][]string{"name": {"kratos"}}, Method: http.MethodPost},
 		res:    nil,
 		w:      responseWriter{},
 	}
@@ -54,7 +54,7 @@ func TestContextForm(t *testing.T) {
 func TestContextQuery(t *testing.T) {
 	w := wrapper{
 		router: testRouter,
-		req:    &http.Request{URL: &url.URL{Scheme: "https", Host: "github.com", Path: "go-kratos/kratos", RawQuery: "page=1"}, Method: "POST"},
+		req:    &http.Request{URL: &url.URL{Scheme: "https", Host: "github.com", Path: "go-kratos/kratos", RawQuery: "page=1"}, Method: http.MethodPost},
 		res:    nil,
 		w:      responseWriter{},
 	}
@@ -65,7 +65,7 @@ func TestContextQuery(t *testing.T) {
 }
 
 func TestContextRequest(t *testing.T) {
-	req := &http.Request{Method: "POST"}
+	req := &http.Request{Method: http.MethodPost}
 	w := wrapper{
 		router: testRouter,
 		req:    req,
@@ -82,7 +82,7 @@ func TestContextResponse(t *testing.T) {
 	res := httptest.NewRecorder()
 	w := wrapper{
 		router: &Router{srv: &Server{enc: DefaultResponseEncoder}},
-		req:    &http.Request{Method: "POST"},
+		req:    &http.Request{Method: http.MethodPost},
 		res:    res,
 		w:      responseWriter{200, res},
 	}
@@ -173,7 +173,7 @@ func TestContextResponseReturn(t *testing.T) {
 func TestContextCtx(t *testing.T) {
 	ctx, cancel := context.WithTimeout(context.Background(), time.Second)
 	defer cancel()
-	req := &http.Request{Method: "POST"}
+	req := &http.Request{Method: http.MethodPost}
 	req = req.WithContext(ctx)
 	w := wrapper{
 		router: testRouter,
diff --git a/transport/http/redirect_test.go b/transport/http/redirect_test.go
index b98bf4f0b..879966a4b 100644
--- a/transport/http/redirect_test.go
+++ b/transport/http/redirect_test.go
@@ -1,6 +1,7 @@
 package http
 
 import (
+	"net/http"
 	"net/http/httptest"
 	"testing"
 )
@@ -10,7 +11,7 @@ func TestRedirect(t *testing.T) {
 		redirectURL  = "/redirect"
 		redirectCode = 302
 	)
-	r := httptest.NewRequest("POST", "/test", nil)
+	r := httptest.NewRequest(http.MethodPost, "/test", nil)
 	w := httptest.NewRecorder()
 	_ = DefaultResponseEncoder(w, r, NewRedirect(redirectURL, redirectCode))
 
diff --git a/transport/http/router_test.go b/transport/http/router_test.go
index ad37831d1..747ebf059 100644
--- a/transport/http/router_test.go
+++ b/transport/http/router_test.go
@@ -136,7 +136,7 @@ func testRoute(t *testing.T, srv *Server) {
 		t.Fatalf("got %s want bar", u.Name)
 	}
 	// PUT
-	req, _ := http.NewRequest("PUT", base+"/users", strings.NewReader(`{"name":"bar"}`))
+	req, _ := http.NewRequest(http.MethodPut, base+"/users", strings.NewReader(`{"name":"bar"}`))
 	req.Header.Set("Content-Type", appJSONStr)
 	resp, err = http.DefaultClient.Do(req)
 	if err != nil {
@@ -157,7 +157,7 @@ func testRoute(t *testing.T, srv *Server) {
 		t.Fatalf("got %s want bar", u.Name)
 	}
 	// OPTIONS
-	req, _ = http.NewRequest("OPTIONS", base+"/users", nil)
+	req, _ = http.NewRequest(http.MethodOptions, base+"/users", nil)
 	resp, err = http.DefaultClient.Do(req)
 	if err != nil {
 		t.Fatal(err)
@@ -166,7 +166,7 @@ func testRoute(t *testing.T, srv *Server) {
 	if resp.StatusCode != 200 {
 		t.Fatalf("code: %d", resp.StatusCode)
 	}
-	if resp.Header.Get("Access-Control-Allow-Methods") != "OPTIONS" {
+	if resp.Header.Get("Access-Control-Allow-Methods") != http.MethodOptions {
 		t.Fatal("cors failed")
 	}
 }
diff --git a/transport/http/server.go b/transport/http/server.go
index b756a0f80..165bb99bc 100644
--- a/transport/http/server.go
+++ b/transport/http/server.go
@@ -128,6 +128,13 @@ func Listener(lis net.Listener) ServerOption {
 	}
 }
 
+// PathPrefix with mux's PathPrefix, router will replaced by a subrouter that start with prefix.
+func PathPrefix(prefix string) ServerOption {
+	return func(s *Server) {
+		s.router = s.router.PathPrefix(prefix).Subrouter()
+	}
+}
+
 // Server is an HTTP server wrapper.
 type Server struct {
 	*http.Server
@@ -162,11 +169,12 @@ func NewServer(opts ...ServerOption) *Server {
 		enc:         DefaultResponseEncoder,
 		ene:         DefaultErrorEncoder,
 		strictSlash: true,
+		router:      mux.NewRouter(),
 	}
 	for _, o := range opts {
 		o(srv)
 	}
-	srv.router = mux.NewRouter().StrictSlash(srv.strictSlash)
+	srv.router.StrictSlash(srv.strictSlash)
 	srv.router.NotFoundHandler = http.DefaultServeMux
 	srv.router.MethodNotAllowedHandler = http.DefaultServeMux
 	srv.router.Use(srv.filter())
diff --git a/transport/http/server_test.go b/transport/http/server_test.go
index ff9b3918c..22865fc33 100644
--- a/transport/http/server_test.go
+++ b/transport/http/server_test.go
@@ -117,8 +117,8 @@ func testAccept(t *testing.T, srv *Server) {
 		path        string
 		contentType string
 	}{
-		{"GET", "/errors/cause", "application/json"},
-		{"GET", "/errors/cause", "application/proto"},
+		{http.MethodGet, "/errors/cause", "application/json"},
+		{http.MethodGet, "/errors/cause", "application/proto"},
 	}
 	e, err := srv.Endpoint()
 	if err != nil {
@@ -154,7 +154,7 @@ func testHeader(t *testing.T, srv *Server) {
 		t.Errorf("expected nil got %v", err)
 	}
 	reqURL := fmt.Sprintf(e.String() + "/index")
-	req, err := http.NewRequest("GET", reqURL, nil)
+	req, err := http.NewRequest(http.MethodGet, reqURL, nil)
 	if err != nil {
 		t.Errorf("expected nil got %v", err)
 	}
@@ -172,21 +172,21 @@ func testClient(t *testing.T, srv *Server) {
 		path   string
 		code   int
 	}{
-		{"GET", "/index", http.StatusOK},
-		{"PUT", "/index", http.StatusOK},
-		{"POST", "/index", http.StatusOK},
-		{"PATCH", "/index", http.StatusOK},
-		{"DELETE", "/index", http.StatusOK},
+		{http.MethodGet, "/index", http.StatusOK},
+		{http.MethodPut, "/index", http.StatusOK},
+		{http.MethodPost, "/index", http.StatusOK},
+		{http.MethodPatch, "/index", http.StatusOK},
+		{http.MethodDelete, "/index", http.StatusOK},
 
-		{"GET", "/index/1", http.StatusOK},
-		{"PUT", "/index/1", http.StatusOK},
-		{"POST", "/index/1", http.StatusOK},
-		{"PATCH", "/index/1", http.StatusOK},
-		{"DELETE", "/index/1", http.StatusOK},
+		{http.MethodGet, "/index/1", http.StatusOK},
+		{http.MethodPut, "/index/1", http.StatusOK},
+		{http.MethodPost, "/index/1", http.StatusOK},
+		{http.MethodPatch, "/index/1", http.StatusOK},
+		{http.MethodDelete, "/index/1", http.StatusOK},
 
-		{"GET", "/index/notfound", http.StatusNotFound},
-		{"GET", "/errors/cause", http.StatusBadRequest},
-		{"GET", "/test/prefix/123111", http.StatusOK},
+		{http.MethodGet, "/index/notfound", http.StatusNotFound},
+		{http.MethodGet, "/errors/cause", http.StatusBadRequest},
+		{http.MethodGet, "/test/prefix/123111", http.StatusOK},
 	}
 	e, err := srv.Endpoint()
 	if err != nil {
@@ -273,7 +273,7 @@ func BenchmarkServer(b *testing.B) {
 	b.ResetTimer()
 	for i := 0; i < b.N; i++ {
 		var res testData
-		err := client.Invoke(context.Background(), "POST", "/index", nil, &res)
+		err := client.Invoke(context.Background(), http.MethodPost, "/index", nil, &res)
 		if err != nil {
 			b.Errorf("expected nil got %v", err)
 		}
diff --git a/version.go b/version.go
index 2c8d6f462..e130ae2cc 100644
--- a/version.go
+++ b/version.go
@@ -1,4 +1,4 @@
 package kratos
 
 // Release is the current kratos version.
-const Release = "v2.5.1"
+const Release = "v2.5.2"