fix(sticky): fix cookie format, shard keying, and tests

- Encode cookie as base64(target_url + | + timestamp) per spec
- Use cookie value (not targetURL) for shard key and session map keys
- Add missing sticky.Start() calls in tests
- Fix time precision in cookie encode/decode tests

internal/loadbalance/sticky.go

@@ -2,6 +2,8 @@ package loadbalance
 
 import (
 	"encoding/base64"
+	"strconv"
+	"strings"
 	"sync"
 	"time"
 
@@ -98,8 +100,8 @@ func (s *StickySession) Select(ctx *fasthttp.RequestCtx, targets []*Target) *Tar
 	// 检查现有 cookie
 	cookieValue := ctx.Request.Header.Cookie(s.config.Name)
 	if len(cookieValue) > 0 {
-		decodedURL, err := decodeStickyCookie(string(cookieValue))
+		decodedURL, _, ok := decodeStickyCookie(string(cookieValue))
-		if err == nil && decodedURL != "" {
+		if ok && decodedURL != "" {
 			// 查找对应的目标
 			for _, target := range targets {
 				if target.URL == decodedURL && target.IsAvailable() {
@@ -107,15 +109,15 @@ func (s *StickySession) Select(ctx *fasthttp.RequestCtx, targets []*Target) *Tar
 				}
 			}
 			// 目标不可用，删除会话记录
-			s.deleteSession(decodedURL)
+			s.deleteSession(string(cookieValue))
 		}
 	}
 
 	// 使用 fallback 选择目标
 	selected := s.fallback.Select(targets)
 	if selected != nil {
-		s.setCookie(ctx, selected.URL)
+		newCookieValue := s.setCookie(ctx, selected.URL)
-		s.recordSession(selected.URL)
+		s.recordSession(newCookieValue, selected.URL)
 	}
 	return selected
 }
@@ -125,14 +127,16 @@ func (s *StickySession) SelectExcluding(targets []*Target, excluded []*Target) *
 	return s.fallback.SelectExcluding(targets, excluded)
 }
 
-// setCookie 设置会话 cookie 到响应头。
+// setCookie 设置会话 cookie 到响应头，返回编码后的 cookie 值。
-func (s *StickySession) setCookie(ctx *fasthttp.RequestCtx, targetURL string) {
+func (s *StickySession) setCookie(ctx *fasthttp.RequestCtx, targetURL string) string {
+	expires := time.Now().Add(s.config.Expires)
 	cookie := &fasthttp.Cookie{}
 	cookie.SetKey(s.config.Name)
-	cookie.SetValue(encodeStickyCookie(targetURL))
+	encoded := encodeStickyCookie(targetURL, expires)
+	cookie.SetValue(encoded)
 
 	if s.config.Expires > 0 {
-		cookie.SetExpire(time.Now().Add(s.config.Expires))
+		cookie.SetExpire(expires)
 	}
 	if s.config.Domain != "" {
 		cookie.SetDomain(s.config.Domain)
@@ -159,13 +163,14 @@ func (s *StickySession) setCookie(ctx *fasthttp.RequestCtx, targetURL string) {
 	}
 
 	ctx.Response.Header.SetCookie(cookie)
+	return encoded
 }
 
 // recordSession 记录会话到 shard 中。
-func (s *StickySession) recordSession(targetURL string) {
+func (s *StickySession) recordSession(cookieValue, targetURL string) {
-	shard := s.getShard(targetURL)
+	shard := s.getShard(cookieValue)
 	shard.mu.Lock()
-	shard.entries[targetURL] = &stickyEntry{
+	shard.entries[cookieValue] = &stickyEntry{
 		targetURL: targetURL,
 		expires:   time.Now().Add(s.config.Expires),
 	}
@@ -173,31 +178,40 @@ func (s *StickySession) recordSession(targetURL string) {
 }
 
 // deleteSession 从 shard 中删除会话记录。
-func (s *StickySession) deleteSession(targetURL string) {
+func (s *StickySession) deleteSession(cookieValue string) {
-	shard := s.getShard(targetURL)
+	shard := s.getShard(cookieValue)
 	shard.mu.Lock()
-	delete(shard.entries, targetURL)
+	delete(shard.entries, cookieValue)
 	shard.mu.Unlock()
 }
 
-// getShard 根据 targetURL 选择对应的 shard。
+// getShard 根据 cookieValue 选择对应的 shard。
-func (s *StickySession) getShard(targetURL string) *stickyShard {
+func (s *StickySession) getShard(cookieValue string) *stickyShard {
-	hash := fnvHash64a(targetURL)
+	hash := fnvHash64a(cookieValue)
 	return s.shards[hash%stickyShardCount]
 }
 
-// encodeStickyCookie 将目标 URL 编码为 cookie 值（base64）。
+// encodeStickyCookie 将目标 URL 和过期时间编码为 cookie 值（base64）。
-func encodeStickyCookie(targetURL string) string {
+func encodeStickyCookie(targetURL string, expires time.Time) string {
-	return base64.URLEncoding.EncodeToString([]byte(targetURL))
+	raw := targetURL + "|" + strconv.FormatInt(expires.Unix(), 10)
+	return base64.URLEncoding.EncodeToString([]byte(raw))
 }
 
-// decodeStickyCookie 解码 cookie 值为目标 URL。
+// decodeStickyCookie 解码 cookie 值为目标 URL 和过期时间。
-func decodeStickyCookie(value string) (string, error) {
+func decodeStickyCookie(value string) (targetURL string, expires time.Time, ok bool) {
-	decoded, err := base64.URLEncoding.DecodeString(value)
+	raw, err := base64.URLEncoding.DecodeString(value)
 	if err != nil {
-		return "", err
+		return
 	}
-	return string(decoded), nil
+	parts := strings.Split(string(raw), "|")
+	if len(parts) != 2 {
+		return
+	}
+	ts, err := strconv.ParseInt(parts[1], 10, 64)
+	if err != nil {
+		return
+	}
+	return parts[0], time.Unix(ts, 0), true
 }
 
 // Ensure StickySession implements the SelectExcluding part of Balancer interface.

internal/loadbalance/sticky_test.go

@@ -3,6 +3,7 @@ package loadbalance
 import (
 	"sync"
 	"testing"
+	"time"
 
 	"github.com/valyala/fasthttp"
 )
@@ -16,6 +17,7 @@ func TestStickySession_BasicRoute(t *testing.T) {
 		config.Enabled = true
 		fallback := NewRoundRobin()
 		sticky := NewStickySession(config, fallback)
+		sticky.Start()
 		defer sticky.Stop()
 
 		targets := []*Target{
@@ -41,6 +43,7 @@ func TestStickySession_BasicRoute(t *testing.T) {
 		config.Enabled = true
 		fallback := NewRoundRobin()
 		sticky := NewStickySession(config, fallback)
+		sticky.Start()
 		defer sticky.Stop()
 
 		targets := []*Target{
@@ -80,6 +83,7 @@ func TestStickySession_BasicRoute(t *testing.T) {
 		config.Enabled = false
 		fallback := NewRoundRobin()
 		sticky := NewStickySession(config, fallback)
+		sticky.Start()
 		defer sticky.Stop()
 
 		targets := []*Target{
@@ -107,6 +111,7 @@ func TestStickySession_TargetUnavailable(t *testing.T) {
 		config.Enabled = true
 		fallback := NewRoundRobin()
 		sticky := NewStickySession(config, fallback)
+		sticky.Start()
 		defer sticky.Stop()
 
 		targets := []*Target{
@@ -155,36 +160,44 @@ func TestStickySession_CookieEncodeDecode(t *testing.T) {
 	t.Parallel()
 	t.Run("编码解码round-trip", func(_ *testing.T) {
 		url := "http://backend1:8080"
-		encoded := encodeStickyCookie(url)
+		expires := time.Now().Add(time.Hour)
+		encoded := encodeStickyCookie(url, expires)
 		if encoded == "" {
 			t.Fatal("encodeStickyCookie() 返回空字符串")
 		}
 
-		decoded, err := decodeStickyCookie(encoded)
+		decodedURL, decodedExpires, ok := decodeStickyCookie(encoded)
-		if err != nil {
+		if !ok {
-			t.Fatalf("decodeStickyCookie() 错误: %v", err)
+			t.Fatal("decodeStickyCookie() returned ok=false")
 		}
 
-		if decoded != url {
+		if decodedURL != url {
-			t.Errorf("解码后 URL = %q, want %q", decoded, url)
+			t.Errorf("解码后 URL = %q, want %q", decodedURL, url)
+		}
+		if decodedExpires.Unix() != expires.Unix() {
+			t.Errorf("解码后 expires = %v, want %v", decodedExpires, expires)
 		}
 	})
 
 	t.Run("空URL编码解码", func(_ *testing.T) {
-		encoded := encodeStickyCookie("")
+		expires := time.Now().Add(time.Hour)
-		decoded, err := decodeStickyCookie(encoded)
+		encoded := encodeStickyCookie("", expires)
-		if err != nil {
+		decodedURL, decodedExpires, ok := decodeStickyCookie(encoded)
-			t.Fatalf("decodeStickyCookie() 错误: %v", err)
+		if !ok {
+			t.Fatal("decodeStickyCookie() returned ok=false")
 		}
-		if decoded != "" {
+		if decodedURL != "" {
-			t.Errorf("解码后 URL = %q, want 空字符串", decoded)
+			t.Errorf("解码后 URL = %q, want 空字符串", decodedURL)
+		}
+		if decodedExpires.Unix() != expires.Unix() {
+			t.Errorf("解码后 expires = %v, want %v", decodedExpires, expires)
 		}
 	})
 
 	t.Run("无效编码", func(_ *testing.T) {
-		_, err := decodeStickyCookie("invalid-base64!!!")
+		decodedURL, decodedExpires, ok := decodeStickyCookie("invalid-base64!!!")
-		if err == nil {
+		if ok {
-			t.Error("decodeStickyCookie() 应返回错误")
+			t.Errorf("decodeStickyCookie() = (%q, %v, %v), want ok=false", decodedURL, decodedExpires, ok)
 		}
 	})
 }
@@ -197,6 +210,7 @@ func TestStickySession_Concurrent(t *testing.T) {
 	config.Enabled = true
 	fallback := NewRoundRobin()
 	sticky := NewStickySession(config, fallback)
+	sticky.Start()
 	defer sticky.Stop()
 
 	targets := []*Target{
@@ -213,7 +227,7 @@ func TestStickySession_Concurrent(t *testing.T) {
 			ctx := &fasthttp.RequestCtx{}
 			// 交替使用有 cookie 和没有 cookie 的请求
 			if idx%2 == 0 {
-				ctx.Request.Header.SetCookie(config.Name, encodeStickyCookie("http://backend1:8080"))
+				ctx.Request.Header.SetCookie(config.Name, encodeStickyCookie("http://backend1:8080", time.Now().Add(time.Hour)))
 			}
 			got := sticky.Select(ctx, targets)
 			if got == nil {
@@ -232,6 +246,7 @@ func TestStickySession_SelectExcluding(t *testing.T) {
 		config.Enabled = true
 		fallback := NewRoundRobin()
 		sticky := NewStickySession(config, fallback)
+		sticky.Start()
 		defer sticky.Stop()
 
 		targets := []*Target{