perf(网关): 实现上游账号连接池隔离

新增隔离策略与连接池缓存回收

连接池大小跟随账号并发并处理代理切换

同步配置默认值与示例并补充测试

backend/internal/service/account_test_service.go

@@ -256,7 +256,7 @@ func (s *AccountTestService) testClaudeAccountConnection(c *gin.Context, account
 		proxyURL = account.Proxy.URL()
 	}
 
-	resp, err := s.httpUpstream.Do(req, proxyURL)
+	resp, err := s.httpUpstream.Do(req, proxyURL, account.ID, account.Concurrency)
 	if err != nil {
 		return s.sendErrorAndEnd(c, fmt.Sprintf("Request failed: %s", err.Error()))
 	}
@@ -371,7 +371,7 @@ func (s *AccountTestService) testOpenAIAccountConnection(c *gin.Context, account
 		proxyURL = account.Proxy.URL()
 	}
 
-	resp, err := s.httpUpstream.Do(req, proxyURL)
+	resp, err := s.httpUpstream.Do(req, proxyURL, account.ID, account.Concurrency)
 	if err != nil {
 		return s.sendErrorAndEnd(c, fmt.Sprintf("Request failed: %s", err.Error()))
 	}
@@ -442,7 +442,7 @@ func (s *AccountTestService) testGeminiAccountConnection(c *gin.Context, account
 		proxyURL = account.Proxy.URL()
 	}
 
-	resp, err := s.httpUpstream.Do(req, proxyURL)
+	resp, err := s.httpUpstream.Do(req, proxyURL, account.ID, account.Concurrency)
 	if err != nil {
 		return s.sendErrorAndEnd(c, fmt.Sprintf("Request failed: %s", err.Error()))
 	}

backend/internal/service/antigravity_gateway_service.go

@@ -230,7 +230,7 @@ func (s *AntigravityGatewayService) Forward(ctx context.Context, c *gin.Context,
 		upstreamReq.Header.Set("Authorization", "Bearer "+accessToken)
 		upstreamReq.Header.Set("User-Agent", antigravity.UserAgent)
 
-		resp, err = s.httpUpstream.Do(upstreamReq, proxyURL)
+		resp, err = s.httpUpstream.Do(upstreamReq, proxyURL, account.ID, account.Concurrency)
 		if err != nil {
 			if attempt < antigravityMaxRetries {
 				log.Printf("Antigravity account %d: upstream request failed, retry %d/%d: %v", account.ID, attempt, antigravityMaxRetries, err)
@@ -380,7 +380,7 @@ func (s *AntigravityGatewayService) ForwardGemini(ctx context.Context, c *gin.Co
 		upstreamReq.Header.Set("Authorization", "Bearer "+accessToken)
 		upstreamReq.Header.Set("User-Agent", antigravity.UserAgent)
 
-		resp, err = s.httpUpstream.Do(upstreamReq, proxyURL)
+		resp, err = s.httpUpstream.Do(upstreamReq, proxyURL, account.ID, account.Concurrency)
 		if err != nil {
 			if attempt < antigravityMaxRetries {
 				log.Printf("Antigravity account %d: upstream request failed, retry %d/%d: %v", account.ID, attempt, antigravityMaxRetries, err)

backend/internal/service/gateway_service.go

@@ -644,7 +644,7 @@ func (s *GatewayService) Forward(ctx context.Context, c *gin.Context, account *A
 		}
 
 		// 发送请求
-		resp, err = s.httpUpstream.Do(upstreamReq, proxyURL)
+		resp, err = s.httpUpstream.Do(upstreamReq, proxyURL, account.ID, account.Concurrency)
 		if err != nil {
 			return nil, fmt.Errorf("upstream request failed: %w", err)
 		}
@@ -1308,7 +1308,7 @@ func (s *GatewayService) ForwardCountTokens(ctx context.Context, c *gin.Context,
 	}
 
 	// 发送请求
-	resp, err := s.httpUpstream.Do(upstreamReq, proxyURL)
+	resp, err := s.httpUpstream.Do(upstreamReq, proxyURL, account.ID, account.Concurrency)
 	if err != nil {
 		s.countTokensError(c, http.StatusBadGateway, "upstream_error", "Request failed")
 		return fmt.Errorf("upstream request failed: %w", err)

backend/internal/service/gemini_messages_compat_service.go

@@ -472,7 +472,7 @@ func (s *GeminiMessagesCompatService) Forward(ctx context.Context, c *gin.Contex
 		}
 		requestIDHeader = idHeader
 
-		resp, err = s.httpUpstream.Do(upstreamReq, proxyURL)
+		resp, err = s.httpUpstream.Do(upstreamReq, proxyURL, account.ID, account.Concurrency)
 		if err != nil {
 			if attempt < geminiMaxRetries {
 				log.Printf("Gemini account %d: upstream request failed, retry %d/%d: %v", account.ID, attempt, geminiMaxRetries, err)
@@ -725,7 +725,7 @@ func (s *GeminiMessagesCompatService) ForwardNative(ctx context.Context, c *gin.
 		}
 		requestIDHeader = idHeader
 
-		resp, err = s.httpUpstream.Do(upstreamReq, proxyURL)
+		resp, err = s.httpUpstream.Do(upstreamReq, proxyURL, account.ID, account.Concurrency)
 		if err != nil {
 			if attempt < geminiMaxRetries {
 				log.Printf("Gemini account %d: upstream request failed, retry %d/%d: %v", account.ID, attempt, geminiMaxRetries, err)
@@ -1756,7 +1756,7 @@ func (s *GeminiMessagesCompatService) ForwardAIStudioGET(ctx context.Context, ac
 		return nil, fmt.Errorf("unsupported account type: %s", account.Type)
 	}
 
-	resp, err := s.httpUpstream.Do(req, proxyURL)
+	resp, err := s.httpUpstream.Do(req, proxyURL, account.ID, account.Concurrency)
 	if err != nil {
 		return nil, err
 	}

backend/internal/service/http_upstream_port.go

@@ -2,8 +2,29 @@ package service
 
 import "net/http"
 
-// HTTPUpstream interface for making HTTP requests to upstream APIs (Claude, OpenAI, etc.)
-// This is a generic interface that can be used for any HTTP-based upstream service.
+// HTTPUpstream 上游 HTTP 请求接口
+// 用于向上游 API（Claude、OpenAI、Gemini 等）发送请求
+// 这是一个通用接口，可用于任何基于 HTTP 的上游服务
+//
+// 设计说明：
+// - 支持可选代理配置
+// - 支持账户级连接池隔离
+// - 实现类负责连接池管理和复用
 type HTTPUpstream interface {
-	Do(req *http.Request, proxyURL string) (*http.Response, error)
+	// Do 执行 HTTP 请求
+	//
+	// 参数:
+	//   - req: HTTP 请求对象，由调用方构建
+	//   - proxyURL: 代理服务器地址，空字符串表示直连
+	//   - accountID: 账户 ID，用于连接池隔离（隔离策略为 account 或 account_proxy 时生效）
+	//   - accountConcurrency: 账户并发限制，用于动态调整连接池大小
+	//
+	// 返回:
+	//   - *http.Response: HTTP 响应，调用方必须关闭 Body
+	//   - error: 请求错误（网络错误、超时等）
+	//
+	// 注意:
+	//   - 调用方必须关闭 resp.Body，否则会导致连接泄漏
+	//   - 响应体可能已被包装以跟踪请求生命周期
+	Do(req *http.Request, proxyURL string, accountID int64, accountConcurrency int) (*http.Response, error)
 }

backend/internal/service/openai_gateway_service.go

@@ -311,7 +311,7 @@ func (s *OpenAIGatewayService) Forward(ctx context.Context, c *gin.Context, acco
 	}
 
 	// Send request
-	resp, err := s.httpUpstream.Do(upstreamReq, proxyURL)
+	resp, err := s.httpUpstream.Do(upstreamReq, proxyURL, account.ID, account.Concurrency)
 	if err != nil {
 		return nil, fmt.Errorf("upstream request failed: %w", err)
 	}