ci(backend): 添加 github actions (#10)

## 变更内容

### CI/CD
- 添加 GitHub Actions 工作流（test + golangci-lint）
- 添加 golangci-lint 配置，启用 errcheck/govet/staticcheck/unused/depguard
- 通过 depguard 强制 service 层不能直接导入 repository

### 错误处理修复
- 修复 CSV 写入、SSE 流式输出、随机数生成等未处理的错误
- GenerateRedeemCode() 现在返回 error

### 资源泄露修复
- 统一使用 defer func() { _ = xxx.Close() }() 模式

### 代码清理
- 移除未使用的常量
- 简化 nil map 检查
- 统一代码格式

backend/internal/config/config.go

@@ -52,7 +52,7 @@ type PricingConfig struct {
 type ServerConfig struct {
 	Host              string `mapstructure:"host"`
 	Port              int    `mapstructure:"port"`
-	Mode              string `mapstructure:"mode"`               // debug/release
+	Mode              string `mapstructure:"mode"`                // debug/release
 	ReadHeaderTimeout int    `mapstructure:"read_header_timeout"` // 读取请求头超时（秒）
 	IdleTimeout       int    `mapstructure:"idle_timeout"`        // 空闲连接超时（秒）
 }
@@ -163,7 +163,7 @@ func setDefaults() {
 	viper.SetDefault("server.port", 8080)
 	viper.SetDefault("server.mode", "debug")
 	viper.SetDefault("server.read_header_timeout", 30) // 30秒读取请求头
-	viper.SetDefault("server.idle_timeout", 120)      // 120秒空闲超时
+	viper.SetDefault("server.idle_timeout", 120)       // 120秒空闲超时
 
 	// Database
 	viper.SetDefault("database.host", "localhost")
@@ -210,10 +210,10 @@ func setDefaults() {
 
 	// TokenRefresh
 	viper.SetDefault("token_refresh.enabled", true)
-	viper.SetDefault("token_refresh.check_interval_minutes", 5)      // 每5分钟检查一次
+	viper.SetDefault("token_refresh.check_interval_minutes", 5)        // 每5分钟检查一次
 	viper.SetDefault("token_refresh.refresh_before_expiry_hours", 1.5) // 提前1.5小时刷新
-	viper.SetDefault("token_refresh.max_retries", 3)                 // 最多重试3次
-	viper.SetDefault("token_refresh.retry_backoff_seconds", 2)       // 重试退避基础2秒
+	viper.SetDefault("token_refresh.max_retries", 3)                   // 最多重试3次
+	viper.SetDefault("token_refresh.retry_backoff_seconds", 2)         // 重试退避基础2秒
 }
 
 func (c *Config) Validate() error {

backend/internal/handler/admin/account_handler.go

@@ -573,7 +573,7 @@ func (h *AccountHandler) GetAvailableModels(c *gin.Context) {
 
 	// For API Key accounts: return models based on model_mapping
 	mapping := account.GetModelMapping()
-	if mapping == nil || len(mapping) == 0 {
+	if len(mapping) == 0 {
 		// No mapping configured, return default models
 		response.Success(c, claude.DefaultModels)
 		return

backend/internal/handler/admin/proxy_handler.go

@@ -236,7 +236,6 @@ func (h *ProxyHandler) GetProxyAccounts(c *gin.Context) {
 	response.Paginated(c, accounts, total, page, pageSize)
 }
 
-
 // BatchCreateProxyItem represents a single proxy in batch create request
 type BatchCreateProxyItem struct {
 	Protocol string `json:"protocol" binding:"required,oneof=http https socks5"`

backend/internal/handler/admin/redeem_handler.go

@@ -156,10 +156,10 @@ func (h *RedeemHandler) Expire(c *gin.Context) {
 func (h *RedeemHandler) GetStats(c *gin.Context) {
 	// Return mock data for now
 	response.Success(c, gin.H{
-		"total_codes":            0,
-		"active_codes":           0,
-		"used_codes":             0,
-		"expired_codes":          0,
+		"total_codes":             0,
+		"active_codes":            0,
+		"used_codes":              0,
+		"expired_codes":           0,
 		"total_value_distributed": 0.0,
 		"by_type": gin.H{
 			"balance":     0,
@@ -187,7 +187,10 @@ func (h *RedeemHandler) Export(c *gin.Context) {
 	writer := csv.NewWriter(&buf)
 
 	// Write header
-	writer.Write([]string{"id", "code", "type", "value", "status", "used_by", "used_at", "created_at"})
+	if err := writer.Write([]string{"id", "code", "type", "value", "status", "used_by", "used_at", "created_at"}); err != nil {
+		response.InternalError(c, "Failed to export redeem codes: "+err.Error())
+		return
+	}
 
 	// Write data rows
 	for _, code := range codes {
@@ -199,7 +202,7 @@ func (h *RedeemHandler) Export(c *gin.Context) {
 		if code.UsedAt != nil {
 			usedAt = code.UsedAt.Format("2006-01-02 15:04:05")
 		}
-		writer.Write([]string{
+		if err := writer.Write([]string{
 			fmt.Sprintf("%d", code.ID),
 			code.Code,
 			code.Type,
@@ -208,10 +211,17 @@ func (h *RedeemHandler) Export(c *gin.Context) {
 			usedBy,
 			usedAt,
 			code.CreatedAt.Format("2006-01-02 15:04:05"),
-		})
+		}); err != nil {
+			response.InternalError(c, "Failed to export redeem codes: "+err.Error())
+			return
+		}
 	}
 
 	writer.Flush()
+	if err := writer.Error(); err != nil {
+		response.InternalError(c, "Failed to export redeem codes: "+err.Error())
+		return
+	}
 
 	c.Header("Content-Type", "text/csv")
 	c.Header("Content-Disposition", "attachment; filename=redeem_codes.csv")

backend/internal/handler/gateway_handler.go

@@ -268,7 +268,9 @@ func (h *GatewayHandler) waitForSlotWithPing(c *gin.Context, slotType string, id
 					c.Header("X-Accel-Buffering", "no")
 					*streamStarted = true
 				}
-				fmt.Fprintf(c.Writer, "data: {\"type\": \"ping\"}\n\n")
+				if _, err := fmt.Fprintf(c.Writer, "data: {\"type\": \"ping\"}\n\n"); err != nil {
+					return nil, err
+				}
 				flusher.Flush()
 			}
 
@@ -414,7 +416,9 @@ func (h *GatewayHandler) handleStreamingAwareError(c *gin.Context, status int, e
 		if ok {
 			// Send error event in SSE format
 			errorEvent := fmt.Sprintf(`data: {"type": "error", "error": {"type": "%s", "message": "%s"}}`+"\n\n", errType, message)
-			fmt.Fprint(c.Writer, errorEvent)
+			if _, err := fmt.Fprint(c.Writer, errorEvent); err != nil {
+				_ = c.Error(err)
+			}
 			flusher.Flush()
 		}
 		return
@@ -574,11 +578,11 @@ func sendMockWarmupStream(c *gin.Context, model string) {
 // sendMockWarmupResponse 发送非流式 mock 响应（用于预热请求拦截）
 func sendMockWarmupResponse(c *gin.Context, model string) {
 	c.JSON(http.StatusOK, gin.H{
-		"id":      "msg_mock_warmup",
-		"type":    "message",
-		"role":    "assistant",
-		"model":   model,
-		"content": []gin.H{{"type": "text", "text": "New Conversation"}},
+		"id":          "msg_mock_warmup",
+		"type":        "message",
+		"role":        "assistant",
+		"model":       model,
+		"content":     []gin.H{{"type": "text", "text": "New Conversation"}},
 		"stop_reason": "end_turn",
 		"usage": gin.H{
 			"input_tokens":  10,

backend/internal/model/account.go

@@ -40,8 +40,8 @@ type Account struct {
 	Extra        JSONB          `gorm:"type:jsonb;default:'{}'" json:"extra"`       // 扩展信息
 	ProxyID      *int64         `gorm:"index" json:"proxy_id"`
 	Concurrency  int            `gorm:"default:3;not null" json:"concurrency"`
-	Priority     int            `gorm:"default:50;not null" json:"priority"`            // 1-100，越小越高
-	Status       string         `gorm:"size:20;default:active;not null" json:"status"`  // active/disabled/error
+	Priority     int            `gorm:"default:50;not null" json:"priority"`           // 1-100，越小越高
+	Status       string         `gorm:"size:20;default:active;not null" json:"status"` // active/disabled/error
 	ErrorMessage string         `gorm:"type:text" json:"error_message"`
 	LastUsedAt   *time.Time     `gorm:"index" json:"last_used_at"`
 	CreatedAt    time.Time      `gorm:"not null" json:"created_at"`
@@ -163,7 +163,7 @@ func (a *Account) GetModelMapping() map[string]string {
 // 如果没有设置模型映射，则支持所有模型
 func (a *Account) IsModelSupported(requestedModel string) bool {
 	mapping := a.GetModelMapping()
-	if mapping == nil || len(mapping) == 0 {
+	if len(mapping) == 0 {
 		return true // 没有映射配置，支持所有模型
 	}
 	_, exists := mapping[requestedModel]
@@ -174,7 +174,7 @@ func (a *Account) IsModelSupported(requestedModel string) bool {
 // 如果没有映射，返回原始模型名
 func (a *Account) GetMappedModel(requestedModel string) string {
 	mapping := a.GetModelMapping()
-	if mapping == nil || len(mapping) == 0 {
+	if len(mapping) == 0 {
 		return requestedModel
 	}
 	if mappedModel, exists := mapping[requestedModel]; exists {

backend/internal/model/group.go

@@ -13,13 +13,13 @@ const (
 )
 
 type Group struct {
-	ID             int64          `gorm:"primaryKey" json:"id"`
-	Name           string         `gorm:"uniqueIndex;size:100;not null" json:"name"`
-	Description    string         `gorm:"type:text" json:"description"`
-	Platform       string         `gorm:"size:50;default:anthropic;not null" json:"platform"` // anthropic/openai/gemini
-	RateMultiplier float64        `gorm:"type:decimal(10,4);default:1.0;not null" json:"rate_multiplier"`
-	IsExclusive    bool           `gorm:"default:false;not null" json:"is_exclusive"`
-	Status         string         `gorm:"size:20;default:active;not null" json:"status"` // active/disabled
+	ID             int64   `gorm:"primaryKey" json:"id"`
+	Name           string  `gorm:"uniqueIndex;size:100;not null" json:"name"`
+	Description    string  `gorm:"type:text" json:"description"`
+	Platform       string  `gorm:"size:50;default:anthropic;not null" json:"platform"` // anthropic/openai/gemini
+	RateMultiplier float64 `gorm:"type:decimal(10,4);default:1.0;not null" json:"rate_multiplier"`
+	IsExclusive    bool    `gorm:"default:false;not null" json:"is_exclusive"`
+	Status         string  `gorm:"size:20;default:active;not null" json:"status"` // active/disabled
 
 	// 订阅功能字段
 	SubscriptionType string   `gorm:"size:20;default:standard;not null" json:"subscription_type"` // standard/subscription

backend/internal/model/redeem_code.go

@@ -9,15 +9,15 @@ import (
 type RedeemCode struct {
 	ID        int64      `gorm:"primaryKey" json:"id"`
 	Code      string     `gorm:"uniqueIndex;size:32;not null" json:"code"`
-	Type      string     `gorm:"size:20;default:balance;not null" json:"type"` // balance/concurrency/subscription
-	Value     float64    `gorm:"type:decimal(20,8);not null" json:"value"`     // 面值(USD)或并发数或有效天数
+	Type      string     `gorm:"size:20;default:balance;not null" json:"type"`  // balance/concurrency/subscription
+	Value     float64    `gorm:"type:decimal(20,8);not null" json:"value"`      // 面值(USD)或并发数或有效天数
 	Status    string     `gorm:"size:20;default:unused;not null" json:"status"` // unused/used
 	UsedBy    *int64     `gorm:"index" json:"used_by"`
 	UsedAt    *time.Time `json:"used_at"`
 	CreatedAt time.Time  `gorm:"not null" json:"created_at"`
 
 	// 订阅类型专用字段
-	GroupID      *int64 `gorm:"index" json:"group_id"`      // 订阅分组ID (仅subscription类型使用)
+	GroupID      *int64 `gorm:"index" json:"group_id"`           // 订阅分组ID (仅subscription类型使用)
 	ValidityDays int    `gorm:"default:30" json:"validity_days"` // 订阅有效天数 (仅subscription类型使用)
 
 	// 关联
@@ -40,8 +40,10 @@ func (r *RedeemCode) CanUse() bool {
 }
 
 // GenerateRedeemCode 生成唯一的兑换码
-func GenerateRedeemCode() string {
+func GenerateRedeemCode() (string, error) {
 	b := make([]byte, 16)
-	rand.Read(b)
-	return hex.EncodeToString(b)
+	if _, err := rand.Read(b); err != nil {
+		return "", err
+	}
+	return hex.EncodeToString(b), nil
 }

backend/internal/model/setting.go

@@ -19,17 +19,17 @@ func (Setting) TableName() string {
 // 设置Key常量
 const (
 	// 注册设置
-	SettingKeyRegistrationEnabled = "registration_enabled"  // 是否开放注册
-	SettingKeyEmailVerifyEnabled  = "email_verify_enabled"  // 是否开启邮件验证
+	SettingKeyRegistrationEnabled = "registration_enabled" // 是否开放注册
+	SettingKeyEmailVerifyEnabled  = "email_verify_enabled" // 是否开启邮件验证
 
 	// 邮件服务设置
-	SettingKeySmtpHost     = "smtp_host"     // SMTP服务器地址
-	SettingKeySmtpPort     = "smtp_port"     // SMTP端口
-	SettingKeySmtpUsername = "smtp_username" // SMTP用户名
-	SettingKeySmtpPassword = "smtp_password" // SMTP密码（加密存储）
-	SettingKeySmtpFrom     = "smtp_from"     // 发件人地址
+	SettingKeySmtpHost     = "smtp_host"      // SMTP服务器地址
+	SettingKeySmtpPort     = "smtp_port"      // SMTP端口
+	SettingKeySmtpUsername = "smtp_username"  // SMTP用户名
+	SettingKeySmtpPassword = "smtp_password"  // SMTP密码（加密存储）
+	SettingKeySmtpFrom     = "smtp_from"      // 发件人地址
 	SettingKeySmtpFromName = "smtp_from_name" // 发件人名称
-	SettingKeySmtpUseTLS   = "smtp_use_tls"  // 是否使用TLS
+	SettingKeySmtpUseTLS   = "smtp_use_tls"   // 是否使用TLS
 
 	// Cloudflare Turnstile 设置
 	SettingKeyTurnstileEnabled   = "turnstile_enabled"    // 是否启用 Turnstile 验证

backend/internal/model/usage_log.go

@@ -37,7 +37,7 @@ type UsageLog struct {
 	OutputCost        float64 `gorm:"type:decimal(20,10);default:0;not null" json:"output_cost"`
 	CacheCreationCost float64 `gorm:"type:decimal(20,10);default:0;not null" json:"cache_creation_cost"`
 	CacheReadCost     float64 `gorm:"type:decimal(20,10);default:0;not null" json:"cache_read_cost"`
-	TotalCost         float64 `gorm:"type:decimal(20,10);default:0;not null" json:"total_cost"`      // 原始总费用
+	TotalCost         float64 `gorm:"type:decimal(20,10);default:0;not null" json:"total_cost"`     // 原始总费用
 	ActualCost        float64 `gorm:"type:decimal(20,10);default:0;not null" json:"actual_cost"`    // 实际扣除费用
 	RateMultiplier    float64 `gorm:"type:decimal(10,4);default:1;not null" json:"rate_multiplier"` // 计费倍率
 

backend/internal/model/user.go

@@ -9,8 +9,8 @@ import (
 )
 
 type User struct {
-	ID    int64  `gorm:"primaryKey" json:"id"`
-	Email string `gorm:"uniqueIndex;size:255;not null" json:"email"`
+	ID            int64          `gorm:"primaryKey" json:"id"`
+	Email         string         `gorm:"uniqueIndex;size:255;not null" json:"email"`
 	PasswordHash  string         `gorm:"size:255;not null" json:"-"`
 	Role          string         `gorm:"size:20;default:user;not null" json:"role"` // admin/user
 	Balance       float64        `gorm:"type:decimal(20,8);default:0;not null" json:"balance"`

backend/internal/pkg/timezone/timezone_test.go

@@ -37,11 +37,15 @@ func TestInitInvalidTimezone(t *testing.T) {
 
 func TestTimeNowAffected(t *testing.T) {
 	// Reset to UTC first
-	Init("UTC")
+	if err := Init("UTC"); err != nil {
+		t.Fatalf("Init failed with UTC: %v", err)
+	}
 	utcNow := time.Now()
 
 	// Switch to Shanghai (UTC+8)
-	Init("Asia/Shanghai")
+	if err := Init("Asia/Shanghai"); err != nil {
+		t.Fatalf("Init failed with Asia/Shanghai: %v", err)
+	}
 	shanghaiNow := time.Now()
 
 	// The times should be the same instant, but different timezone representation
@@ -58,7 +62,9 @@ func TestTimeNowAffected(t *testing.T) {
 }
 
 func TestToday(t *testing.T) {
-	Init("Asia/Shanghai")
+	if err := Init("Asia/Shanghai"); err != nil {
+		t.Fatalf("Init failed with Asia/Shanghai: %v", err)
+	}
 
 	today := Today()
 	now := Now()
@@ -75,7 +81,9 @@ func TestToday(t *testing.T) {
 }
 
 func TestStartOfDay(t *testing.T) {
-	Init("Asia/Shanghai")
+	if err := Init("Asia/Shanghai"); err != nil {
+		t.Fatalf("Init failed with Asia/Shanghai: %v", err)
+	}
 
 	// Create a time at 15:30:45
 	testTime := time.Date(2024, 6, 15, 15, 30, 45, 123456789, Location())
@@ -91,7 +99,9 @@ func TestTruncateVsStartOfDay(t *testing.T) {
 	// This test demonstrates why Truncate(24*time.Hour) can be problematic
 	// and why StartOfDay is more reliable for timezone-aware code
 
-	Init("Asia/Shanghai")
+	if err := Init("Asia/Shanghai"); err != nil {
+		t.Fatalf("Init failed with Asia/Shanghai: %v", err)
+	}
 
 	now := Now()
 

backend/internal/repository/claude_usage_service.go

@@ -43,7 +43,7 @@ func (s *claudeUsageService) FetchUsage(ctx context.Context, accessToken, proxyU
 	if err != nil {
 		return nil, fmt.Errorf("request failed: %w", err)
 	}
-	defer resp.Body.Close()
+	defer func() { _ = resp.Body.Close() }()
 
 	if resp.StatusCode != http.StatusOK {
 		body, _ := io.ReadAll(resp.Body)

backend/internal/repository/github_release_service.go

@@ -38,7 +38,7 @@ func (c *githubReleaseClient) FetchLatestRelease(ctx context.Context, repo strin
 	if err != nil {
 		return nil, err
 	}
-	defer resp.Body.Close()
+	defer func() { _ = resp.Body.Close() }()
 
 	if resp.StatusCode != http.StatusOK {
 		return nil, fmt.Errorf("GitHub API returned %d", resp.StatusCode)
@@ -63,7 +63,7 @@ func (c *githubReleaseClient) DownloadFile(ctx context.Context, url, dest string
 	if err != nil {
 		return err
 	}
-	defer resp.Body.Close()
+	defer func() { _ = resp.Body.Close() }()
 
 	if resp.StatusCode != http.StatusOK {
 		return fmt.Errorf("download returned %d", resp.StatusCode)
@@ -78,7 +78,7 @@ func (c *githubReleaseClient) DownloadFile(ctx context.Context, url, dest string
 	if err != nil {
 		return err
 	}
-	defer out.Close()
+	defer func() { _ = out.Close() }()
 
 	// SECURITY: Use LimitReader to enforce max download size even if Content-Length is missing/wrong
 	limited := io.LimitReader(resp.Body, maxSize+1)
@@ -89,7 +89,7 @@ func (c *githubReleaseClient) DownloadFile(ctx context.Context, url, dest string
 
 	// Check if we hit the limit (downloaded more than maxSize)
 	if written > maxSize {
-		os.Remove(dest) // Clean up partial file
+		_ = os.Remove(dest) // Clean up partial file (best-effort)
 		return fmt.Errorf("download exceeded maximum size of %d bytes", maxSize)
 	}
 
@@ -106,7 +106,7 @@ func (c *githubReleaseClient) FetchChecksumFile(ctx context.Context, url string)
 	if err != nil {
 		return nil, err
 	}
-	defer resp.Body.Close()
+	defer func() { _ = resp.Body.Close() }()
 
 	if resp.StatusCode != http.StatusOK {
 		return nil, fmt.Errorf("HTTP %d", resp.StatusCode)

backend/internal/repository/pricing_service.go

@@ -33,7 +33,7 @@ func (c *pricingRemoteClient) FetchPricingJSON(ctx context.Context, url string)
 	if err != nil {
 		return nil, err
 	}
-	defer resp.Body.Close()
+	defer func() { _ = resp.Body.Close() }()
 
 	if resp.StatusCode != http.StatusOK {
 		return nil, fmt.Errorf("HTTP %d", resp.StatusCode)
@@ -52,7 +52,7 @@ func (c *pricingRemoteClient) FetchHashText(ctx context.Context, url string) (st
 	if err != nil {
 		return "", err
 	}
-	defer resp.Body.Close()
+	defer func() { _ = resp.Body.Close() }()
 
 	if resp.StatusCode != http.StatusOK {
 		return "", fmt.Errorf("HTTP %d", resp.StatusCode)

backend/internal/repository/proxy_probe_service.go

@@ -43,7 +43,7 @@ func (s *proxyProbeService) ProbeProxy(ctx context.Context, proxyURL string) (*s
 	if err != nil {
 		return nil, 0, fmt.Errorf("proxy connection failed: %w", err)
 	}
-	defer resp.Body.Close()
+	defer func() { _ = resp.Body.Close() }()
 
 	latencyMs := time.Since(startTime).Milliseconds()
 

backend/internal/repository/turnstile_service.go

@@ -44,7 +44,7 @@ func (v *turnstileVerifier) VerifyToken(ctx context.Context, secretKey, token, r
 	if err != nil {
 		return nil, fmt.Errorf("send request: %w", err)
 	}
-	defer resp.Body.Close()
+	defer func() { _ = resp.Body.Close() }()
 
 	var result service.TurnstileVerifyResponse
 	if err := json.NewDecoder(resp.Body).Decode(&result); err != nil {

backend/internal/service/account_test_service.go

@@ -51,16 +51,23 @@ func NewAccountTestService(accountRepo ports.AccountRepository, oauthService *OA
 }
 
 // generateSessionString generates a Claude Code style session string
-func generateSessionString() string {
+func generateSessionString() (string, error) {
 	bytes := make([]byte, 32)
-	rand.Read(bytes)
+	if _, err := rand.Read(bytes); err != nil {
+		return "", err
+	}
 	hex64 := hex.EncodeToString(bytes)
 	sessionUUID := uuid.New().String()
-	return fmt.Sprintf("user_%s_account__session_%s", hex64, sessionUUID)
+	return fmt.Sprintf("user_%s_account__session_%s", hex64, sessionUUID), nil
 }
 
 // createTestPayload creates a Claude Code style test request payload
-func createTestPayload(modelID string) map[string]interface{} {
+func createTestPayload(modelID string) (map[string]interface{}, error) {
+	sessionID, err := generateSessionString()
+	if err != nil {
+		return nil, err
+	}
+
 	return map[string]interface{}{
 		"model": modelID,
 		"messages": []map[string]interface{}{
@@ -87,12 +94,12 @@ func createTestPayload(modelID string) map[string]interface{} {
 			},
 		},
 		"metadata": map[string]string{
-			"user_id": generateSessionString(),
+			"user_id": sessionID,
 		},
 		"max_tokens":  1024,
 		"temperature": 1,
 		"stream":      true,
-	}
+	}, nil
 }
 
 // TestAccountConnection tests an account's connection by sending a test request
@@ -116,7 +123,7 @@ func (s *AccountTestService) TestAccountConnection(c *gin.Context, accountID int
 	// For API Key accounts with model mapping, map the model
 	if account.Type == "apikey" {
 		mapping := account.GetModelMapping()
-		if mapping != nil && len(mapping) > 0 {
+		if len(mapping) > 0 {
 			if mappedModel, exists := mapping[testModelID]; exists {
 				testModelID = mappedModel
 			}
@@ -178,7 +185,10 @@ func (s *AccountTestService) TestAccountConnection(c *gin.Context, accountID int
 	c.Writer.Flush()
 
 	// Create Claude Code style payload (same for all account types)
-	payload := createTestPayload(testModelID)
+	payload, err := createTestPayload(testModelID)
+	if err != nil {
+		return s.sendErrorAndEnd(c, "Failed to create test payload")
+	}
 	payloadBytes, _ := json.Marshal(payload)
 
 	// Send test_start event
@@ -216,7 +226,7 @@ func (s *AccountTestService) TestAccountConnection(c *gin.Context, accountID int
 	if err != nil {
 		return s.sendErrorAndEnd(c, fmt.Sprintf("Request failed: %s", err.Error()))
 	}
-	defer resp.Body.Close()
+	defer func() { _ = resp.Body.Close() }()
 
 	if resp.StatusCode != http.StatusOK {
 		body, _ := io.ReadAll(resp.Body)
@@ -284,7 +294,10 @@ func (s *AccountTestService) processStream(c *gin.Context, body io.Reader) error
 // sendEvent sends a SSE event to the client
 func (s *AccountTestService) sendEvent(c *gin.Context, event TestEvent) {
 	eventJSON, _ := json.Marshal(event)
-	fmt.Fprintf(c.Writer, "data: %s\n\n", eventJSON)
+	if _, err := fmt.Fprintf(c.Writer, "data: %s\n\n", eventJSON); err != nil {
+		log.Printf("failed to write SSE event: %v", err)
+		return
+	}
 	c.Writer.Flush()
 }
 

backend/internal/service/admin_service.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"log"
 	"time"
 
 	"sub2api/internal/model"
@@ -309,7 +310,9 @@ func (s *adminServiceImpl) UpdateUser(ctx context.Context, id int64, input *Upda
 			go func() {
 				cacheCtx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
 				defer cancel()
-				s.billingCacheService.InvalidateUserBalance(cacheCtx, id)
+				if err := s.billingCacheService.InvalidateUserBalance(cacheCtx, id); err != nil {
+					log.Printf("invalidate user balance cache failed: user_id=%d err=%v", id, err)
+				}
 			}()
 		}
 	}
@@ -317,8 +320,13 @@ func (s *adminServiceImpl) UpdateUser(ctx context.Context, id int64, input *Upda
 	// Create adjustment records for balance/concurrency changes
 	balanceDiff := user.Balance - oldBalance
 	if balanceDiff != 0 {
+		code, err := model.GenerateRedeemCode()
+		if err != nil {
+			log.Printf("failed to generate adjustment redeem code: %v", err)
+			return user, nil
+		}
 		adjustmentRecord := &model.RedeemCode{
-			Code:   model.GenerateRedeemCode(),
+			Code:   code,
 			Type:   model.AdjustmentTypeAdminBalance,
 			Value:  balanceDiff,
 			Status: model.StatusUsed,
@@ -327,15 +335,19 @@ func (s *adminServiceImpl) UpdateUser(ctx context.Context, id int64, input *Upda
 		now := time.Now()
 		adjustmentRecord.UsedAt = &now
 		if err := s.redeemCodeRepo.Create(ctx, adjustmentRecord); err != nil {
-			// Log error but don't fail the update
-			// The user update has already succeeded
+			log.Printf("failed to create balance adjustment redeem code: %v", err)
 		}
 	}
 
 	concurrencyDiff := user.Concurrency - oldConcurrency
 	if concurrencyDiff != 0 {
+		code, err := model.GenerateRedeemCode()
+		if err != nil {
+			log.Printf("failed to generate adjustment redeem code: %v", err)
+			return user, nil
+		}
 		adjustmentRecord := &model.RedeemCode{
-			Code:   model.GenerateRedeemCode(),
+			Code:   code,
 			Type:   model.AdjustmentTypeAdminConcurrency,
 			Value:  float64(concurrencyDiff),
 			Status: model.StatusUsed,
@@ -344,8 +356,7 @@ func (s *adminServiceImpl) UpdateUser(ctx context.Context, id int64, input *Upda
 		now := time.Now()
 		adjustmentRecord.UsedAt = &now
 		if err := s.redeemCodeRepo.Create(ctx, adjustmentRecord); err != nil {
-			// Log error but don't fail the update
-			// The user update has already succeeded
+			log.Printf("failed to create concurrency adjustment redeem code: %v", err)
 		}
 	}
 
@@ -388,7 +399,9 @@ func (s *adminServiceImpl) UpdateUserBalance(ctx context.Context, userID int64,
 		go func() {
 			cacheCtx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
 			defer cancel()
-			s.billingCacheService.InvalidateUserBalance(cacheCtx, userID)
+			if err := s.billingCacheService.InvalidateUserBalance(cacheCtx, userID); err != nil {
+				log.Printf("invalidate user balance cache failed: user_id=%d err=%v", userID, err)
+			}
 		}()
 	}
 
@@ -579,7 +592,9 @@ func (s *adminServiceImpl) DeleteGroup(ctx context.Context, id int64) error {
 			cacheCtx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
 			defer cancel()
 			for _, userID := range affectedUserIDs {
-				s.billingCacheService.InvalidateSubscription(cacheCtx, userID, groupID)
+				if err := s.billingCacheService.InvalidateSubscription(cacheCtx, userID, groupID); err != nil {
+					log.Printf("invalidate subscription cache failed: user_id=%d group_id=%d err=%v", userID, groupID, err)
+				}
 			}
 		}()
 	}
@@ -646,10 +661,10 @@ func (s *adminServiceImpl) UpdateAccount(ctx context.Context, id int64, input *U
 	if input.Type != "" {
 		account.Type = input.Type
 	}
-	if input.Credentials != nil && len(input.Credentials) > 0 {
+	if len(input.Credentials) > 0 {
 		account.Credentials = model.JSONB(input.Credentials)
 	}
-	if input.Extra != nil && len(input.Extra) > 0 {
+	if len(input.Extra) > 0 {
 		account.Extra = model.JSONB(input.Extra)
 	}
 	if input.ProxyID != nil {
@@ -831,8 +846,12 @@ func (s *adminServiceImpl) GenerateRedeemCodes(ctx context.Context, input *Gener
 
 	codes := make([]model.RedeemCode, 0, input.Count)
 	for i := 0; i < input.Count; i++ {
+		codeValue, err := model.GenerateRedeemCode()
+		if err != nil {
+			return nil, err
+		}
 		code := model.RedeemCode{
-			Code:   model.GenerateRedeemCode(),
+			Code:   codeValue,
 			Type:   input.Type,
 			Value:  input.Value,
 			Status: model.StatusUnused,

backend/internal/service/api_key_service.go

@@ -100,10 +100,13 @@ func (s *ApiKeyService) ValidateCustomKey(key string) error {
 
 	// 检查字符：只允许字母、数字、下划线、连字符
 	for _, c := range key {
-		if !((c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z') ||
-			(c >= '0' && c <= '9') || c == '_' || c == '-') {
-			return ErrApiKeyInvalidChars
+		if (c >= 'a' && c <= 'z') ||
+			(c >= 'A' && c <= 'Z') ||
+			(c >= '0' && c <= '9') ||
+			c == '_' || c == '-' {
+			continue
 		}
+		return ErrApiKeyInvalidChars
 	}
 
 	return nil

backend/internal/service/concurrency_service.go

@@ -9,12 +9,6 @@ import (
 )
 
 const (
-	// Wait polling interval
-	waitPollInterval = 100 * time.Millisecond
-
-	// Default max wait time
-	defaultMaxWait = 60 * time.Second
-
 	// Default extra wait slots beyond concurrency limit
 	defaultExtraWaitSlots = 20
 )
@@ -31,7 +25,7 @@ func NewConcurrencyService(cache ports.ConcurrencyCache) *ConcurrencyService {
 
 // AcquireResult represents the result of acquiring a concurrency slot
 type AcquireResult struct {
-	Acquired   bool
+	Acquired    bool
 	ReleaseFunc func() // Must be called when done (typically via defer)
 }
 
@@ -54,7 +48,7 @@ func (s *ConcurrencyService) AcquireAccountSlot(ctx context.Context, accountID i
 
 	if acquired {
 		return &AcquireResult{
-			Acquired:    true,
+			Acquired: true,
 			ReleaseFunc: func() {
 				bgCtx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
 				defer cancel()
@@ -90,7 +84,7 @@ func (s *ConcurrencyService) AcquireUserSlot(ctx context.Context, userID int64,
 
 	if acquired {
 		return &AcquireResult{
-			Acquired:    true,
+			Acquired: true,
 			ReleaseFunc: func() {
 				bgCtx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
 				defer cancel()

backend/internal/service/email_service.go

@@ -133,13 +133,13 @@ func (s *EmailService) sendMailTLS(addr string, auth smtp.Auth, from, to string,
 	if err != nil {
 		return fmt.Errorf("tls dial: %w", err)
 	}
-	defer conn.Close()
+	defer func() { _ = conn.Close() }()
 
 	client, err := smtp.NewClient(conn, host)
 	if err != nil {
 		return fmt.Errorf("new smtp client: %w", err)
 	}
-	defer client.Close()
+	defer func() { _ = client.Close() }()
 
 	if err = client.Auth(auth); err != nil {
 		return fmt.Errorf("smtp auth: %w", err)
@@ -303,13 +303,13 @@ func (s *EmailService) TestSmtpConnectionWithConfig(config *SmtpConfig) error {
 		if err != nil {
 			return fmt.Errorf("tls connection failed: %w", err)
 		}
-		defer conn.Close()
+		defer func() { _ = conn.Close() }()
 
 		client, err := smtp.NewClient(conn, config.Host)
 		if err != nil {
 			return fmt.Errorf("smtp client creation failed: %w", err)
 		}
-		defer client.Close()
+		defer func() { _ = client.Close() }()
 
 		auth := smtp.PlainAuth("", config.Username, config.Password, config.Host)
 		if err = client.Auth(auth); err != nil {
@@ -324,7 +324,7 @@ func (s *EmailService) TestSmtpConnectionWithConfig(config *SmtpConfig) error {
 	if err != nil {
 		return fmt.Errorf("smtp connection failed: %w", err)
 	}
-	defer client.Close()
+	defer func() { _ = client.Close() }()
 
 	auth := smtp.PlainAuth("", config.Username, config.Password, config.Host)
 	if err = client.Auth(auth); err != nil {

backend/internal/service/gateway_service.go

@@ -281,7 +281,9 @@ func (s *GatewayService) SelectAccountForModel(ctx context.Context, groupID *int
 			// 同时检查模型支持
 			if err == nil && account.IsSchedulable() && (requestedModel == "" || account.IsModelSupported(requestedModel)) {
 				// 续期粘性会话
-				s.cache.RefreshSessionTTL(ctx, sessionHash, stickySessionTTL)
+				if err := s.cache.RefreshSessionTTL(ctx, sessionHash, stickySessionTTL); err != nil {
+					log.Printf("refresh session ttl failed: session=%s err=%v", sessionHash, err)
+				}
 				return account, nil
 			}
 		}
@@ -331,7 +333,9 @@ func (s *GatewayService) SelectAccountForModel(ctx context.Context, groupID *int
 
 	// 4. 建立粘性绑定
 	if sessionHash != "" {
-		s.cache.SetSessionAccountID(ctx, sessionHash, selected.ID, stickySessionTTL)
+		if err := s.cache.SetSessionAccountID(ctx, sessionHash, selected.ID, stickySessionTTL); err != nil {
+			log.Printf("set session account failed: session=%s account_id=%d err=%v", sessionHash, selected.ID, err)
+		}
 	}
 
 	return selected, nil
@@ -411,7 +415,7 @@ func (s *GatewayService) Forward(ctx context.Context, c *gin.Context, account *m
 	if err != nil {
 		return nil, fmt.Errorf("upstream request failed: %w", err)
 	}
-	defer resp.Body.Close()
+	defer func() { _ = resp.Body.Close() }()
 
 	// 处理错误响应（包括401，由后台TokenRefreshService维护token有效性）
 	if resp.StatusCode >= 400 {
@@ -678,7 +682,9 @@ func (s *GatewayService) handleStreamingResponse(ctx context.Context, resp *http
 		}
 
 		// 转发行
-		fmt.Fprintf(w, "%s\n", line)
+		if _, err := fmt.Fprintf(w, "%s\n", line); err != nil {
+			return &streamingResult{usage: usage, firstTokenMs: firstTokenMs}, err
+		}
 		flusher.Flush()
 
 		// 解析usage数据
@@ -985,7 +991,9 @@ func (s *GatewayService) ForwardCountTokens(ctx context.Context, c *gin.Context,
 		s.countTokensError(c, http.StatusBadGateway, "upstream_error", "Request failed")
 		return fmt.Errorf("upstream request failed: %w", err)
 	}
-	defer resp.Body.Close()
+	defer func() {
+		_ = resp.Body.Close()
+	}()
 
 	// 读取响应体
 	respBody, err := io.ReadAll(resp.Body)

backend/internal/service/identity_service.go

@@ -15,7 +15,6 @@ import (
 	"time"
 )
 
-
 // 预编译正则表达式（避免每次调用重新编译）
 var (
 	// 匹配 user_id 格式: user_{64位hex}_account__session_{uuid}

backend/internal/service/redeem_service.go

@@ -254,7 +254,7 @@ func (s *RedeemService) Redeem(ctx context.Context, userID int64, code string) (
 			go func() {
 				cacheCtx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
 				defer cancel()
-				s.billingCacheService.InvalidateUserBalance(cacheCtx, userID)
+				_ = s.billingCacheService.InvalidateUserBalance(cacheCtx, userID)
 			}()
 		}
 
@@ -285,7 +285,7 @@ func (s *RedeemService) Redeem(ctx context.Context, userID int64, code string) (
 			go func() {
 				cacheCtx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
 				defer cancel()
-				s.billingCacheService.InvalidateSubscription(cacheCtx, userID, groupID)
+				_ = s.billingCacheService.InvalidateSubscription(cacheCtx, userID, groupID)
 			}()
 		}
 

backend/internal/service/subscription_service.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"log"
 	"time"
 
 	"sub2api/internal/model"
@@ -78,7 +79,7 @@ func (s *SubscriptionService) AssignSubscription(ctx context.Context, input *Ass
 		go func() {
 			cacheCtx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
 			defer cancel()
-			s.billingCacheService.InvalidateSubscription(cacheCtx, userID, groupID)
+			_ = s.billingCacheService.InvalidateSubscription(cacheCtx, userID, groupID)
 		}()
 	}
 
@@ -146,7 +147,7 @@ func (s *SubscriptionService) AssignOrExtendSubscription(ctx context.Context, in
 			}
 			newNotes += input.Notes
 			if err := s.userSubRepo.UpdateNotes(ctx, existingSub.ID, newNotes); err != nil {
-				// 备注更新失败不影响主流程
+				log.Printf("update subscription notes failed: sub_id=%d err=%v", existingSub.ID, err)
 			}
 		}
 
@@ -156,7 +157,7 @@ func (s *SubscriptionService) AssignOrExtendSubscription(ctx context.Context, in
 			go func() {
 				cacheCtx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
 				defer cancel()
-				s.billingCacheService.InvalidateSubscription(cacheCtx, userID, groupID)
+				_ = s.billingCacheService.InvalidateSubscription(cacheCtx, userID, groupID)
 			}()
 		}
 
@@ -177,7 +178,7 @@ func (s *SubscriptionService) AssignOrExtendSubscription(ctx context.Context, in
 		go func() {
 			cacheCtx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
 			defer cancel()
-			s.billingCacheService.InvalidateSubscription(cacheCtx, userID, groupID)
+			_ = s.billingCacheService.InvalidateSubscription(cacheCtx, userID, groupID)
 		}()
 	}
 
@@ -278,7 +279,7 @@ func (s *SubscriptionService) RevokeSubscription(ctx context.Context, subscripti
 		go func() {
 			cacheCtx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
 			defer cancel()
-			s.billingCacheService.InvalidateSubscription(cacheCtx, userID, groupID)
+			_ = s.billingCacheService.InvalidateSubscription(cacheCtx, userID, groupID)
 		}()
 	}
 
@@ -311,7 +312,7 @@ func (s *SubscriptionService) ExtendSubscription(ctx context.Context, subscripti
 		go func() {
 			cacheCtx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
 			defer cancel()
-			s.billingCacheService.InvalidateSubscription(cacheCtx, userID, groupID)
+			_ = s.billingCacheService.InvalidateSubscription(cacheCtx, userID, groupID)
 		}()
 	}
 

backend/internal/service/turnstile_service.go

@@ -12,8 +12,6 @@ var (
 	ErrTurnstileNotConfigured      = errors.New("turnstile not configured")
 )
 
-const turnstileVerifyURL = "https://challenges.cloudflare.com/turnstile/v0/siteverify"
-
 // TurnstileVerifier 验证 Turnstile token 的接口
 type TurnstileVerifier interface {
 	VerifyToken(ctx context.Context, secretKey, token, remoteIP string) (*TurnstileVerifyResponse, error)

backend/internal/service/update_service.go

@@ -14,6 +14,7 @@ import (
 	"os"
 	"path/filepath"
 	"runtime"
+	"strconv"
 	"strings"
 	"time"
 
@@ -190,7 +191,7 @@ func (s *UpdateService) PerformUpdate(ctx context.Context) error {
 	if err != nil {
 		return fmt.Errorf("failed to create temp dir: %w", err)
 	}
-	defer os.RemoveAll(tempDir)
+	defer func() { _ = os.RemoveAll(tempDir) }()
 
 	// Download archive
 	archivePath := filepath.Join(tempDir, filepath.Base(downloadURL))
@@ -223,7 +224,7 @@ func (s *UpdateService) PerformUpdate(ctx context.Context) error {
 	backupPath := exePath + ".backup"
 
 	// Remove old backup if exists
-	os.Remove(backupPath)
+	_ = os.Remove(backupPath)
 
 	// Step 1: Move current binary to backup
 	if err := os.Rename(exePath, backupPath); err != nil {
@@ -349,7 +350,7 @@ func (s *UpdateService) verifyChecksum(ctx context.Context, filePath, checksumUR
 	if err != nil {
 		return err
 	}
-	defer f.Close()
+	defer func() { _ = f.Close() }()
 
 	h := sha256.New()
 	if _, err := io.Copy(h, f); err != nil {
@@ -379,7 +380,7 @@ func (s *UpdateService) extractBinary(archivePath, destPath string) error {
 	if err != nil {
 		return err
 	}
-	defer f.Close()
+	defer func() { _ = f.Close() }()
 
 	var reader io.Reader = f
 
@@ -389,7 +390,7 @@ func (s *UpdateService) extractBinary(archivePath, destPath string) error {
 		if err != nil {
 			return err
 		}
-		defer gzr.Close()
+		defer func() { _ = gzr.Close() }()
 		reader = gzr
 	}
 
@@ -435,10 +436,12 @@ func (s *UpdateService) extractBinary(archivePath, destPath string) error {
 				// Use LimitReader to prevent decompression bombs
 				limited := io.LimitReader(tr, maxBinarySize)
 				if _, err := io.Copy(out, limited); err != nil {
-					out.Close()
+					_ = out.Close()
+					return err
+				}
+				if err := out.Close(); err != nil {
 					return err
 				}
-				out.Close()
 				return nil
 			}
 		}
@@ -451,11 +454,13 @@ func (s *UpdateService) extractBinary(archivePath, destPath string) error {
 	if err != nil {
 		return err
 	}
-	defer out.Close()
 
 	limited := io.LimitReader(reader, maxBinarySize)
-	_, err = io.Copy(out, limited)
-	return err
+	if _, err := io.Copy(out, limited); err != nil {
+		_ = out.Close()
+		return err
+	}
+	return out.Close()
 }
 
 func (s *UpdateService) getFromCache(ctx context.Context) (*UpdateInfo, error) {
@@ -499,7 +504,7 @@ func (s *UpdateService) saveToCache(ctx context.Context, info *UpdateInfo) {
 	}
 
 	data, _ := json.Marshal(cacheData)
-	s.cache.SetUpdateInfo(ctx, string(data), time.Duration(updateCacheTTL)*time.Second)
+	_ = s.cache.SetUpdateInfo(ctx, string(data), time.Duration(updateCacheTTL)*time.Second)
 }
 
 // compareVersions compares two semantic versions
@@ -523,7 +528,9 @@ func parseVersion(v string) [3]int {
 	parts := strings.Split(v, ".")
 	result := [3]int{0, 0, 0}
 	for i := 0; i < len(parts) && i < 3; i++ {
-		fmt.Sscanf(parts[i], "%d", &result[i])
+		if parsed, err := strconv.Atoi(parts[i]); err == nil {
+			result[i] = parsed
+		}
 	}
 	return result
 }

backend/internal/setup/handler.go

@@ -352,4 +352,3 @@ func install(c *gin.Context) {
 		"restart": true,
 	})
 }
-

backend/internal/setup/setup.go

@@ -14,9 +14,9 @@ import (
 
 	"github.com/redis/go-redis/v9"
 	"golang.org/x/crypto/bcrypt"
+	"gopkg.in/yaml.v3"
 	"gorm.io/driver/postgres"
 	"gorm.io/gorm"
-	"gopkg.in/yaml.v3"
 )
 
 // Config paths
@@ -101,7 +101,14 @@ func TestDatabaseConnection(cfg *DatabaseConfig) error {
 	if err != nil {
 		return fmt.Errorf("failed to get db instance: %w", err)
 	}
-	defer sqlDB.Close()
+	defer func() {
+		if sqlDB == nil {
+			return
+		}
+		if err := sqlDB.Close(); err != nil {
+			log.Printf("failed to close postgres connection: %v", err)
+		}
+	}()
 
 	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
 	defer cancel()
@@ -129,7 +136,10 @@ func TestDatabaseConnection(cfg *DatabaseConfig) error {
 	}
 
 	// Now connect to the target database to verify
-	sqlDB.Close()
+	if err := sqlDB.Close(); err != nil {
+		log.Printf("failed to close postgres connection: %v", err)
+	}
+	sqlDB = nil
 
 	targetDSN := fmt.Sprintf(
 		"host=%s port=%d user=%s password=%s dbname=%s sslmode=%s",
@@ -145,7 +155,11 @@ func TestDatabaseConnection(cfg *DatabaseConfig) error {
 	if err != nil {
 		return fmt.Errorf("failed to get target db instance: %w", err)
 	}
-	defer targetSqlDB.Close()
+	defer func() {
+		if err := targetSqlDB.Close(); err != nil {
+			log.Printf("failed to close postgres connection: %v", err)
+		}
+	}()
 
 	ctx2, cancel2 := context.WithTimeout(context.Background(), 5*time.Second)
 	defer cancel2()
@@ -164,7 +178,11 @@ func TestRedisConnection(cfg *RedisConfig) error {
 		Password: cfg.Password,
 		DB:       cfg.DB,
 	})
-	defer rdb.Close()
+	defer func() {
+		if err := rdb.Close(); err != nil {
+			log.Printf("failed to close redis client: %v", err)
+		}
+	}()
 
 	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
 	defer cancel()
@@ -185,7 +203,11 @@ func Install(cfg *SetupConfig) error {
 
 	// Generate JWT secret if not provided
 	if cfg.JWT.Secret == "" {
-		cfg.JWT.Secret = generateSecret(32)
+		secret, err := generateSecret(32)
+		if err != nil {
+			return fmt.Errorf("failed to generate jwt secret: %w", err)
+		}
+		cfg.JWT.Secret = secret
 	}
 
 	// Test connections
@@ -243,7 +265,11 @@ func initializeDatabase(cfg *SetupConfig) error {
 	if err != nil {
 		return err
 	}
-	defer sqlDB.Close()
+	defer func() {
+		if err := sqlDB.Close(); err != nil {
+			log.Printf("failed to close postgres connection: %v", err)
+		}
+	}()
 
 	// 使用 model 包的 AutoMigrate，确保模型定义统一
 	return model.AutoMigrate(db)
@@ -265,7 +291,11 @@ func createAdminUser(cfg *SetupConfig) error {
 	if err != nil {
 		return err
 	}
-	defer sqlDB.Close()
+	defer func() {
+		if err := sqlDB.Close(); err != nil {
+			log.Printf("failed to close postgres connection: %v", err)
+		}
+	}()
 
 	// Check if admin already exists
 	var count int64
@@ -352,10 +382,12 @@ func writeConfigFile(cfg *SetupConfig) error {
 	return os.WriteFile(ConfigFile, data, 0600)
 }
 
-func generateSecret(length int) string {
+func generateSecret(length int) (string, error) {
 	bytes := make([]byte, length)
-	rand.Read(bytes)
-	return hex.EncodeToString(bytes)
+	if _, err := rand.Read(bytes); err != nil {
+		return "", err
+	}
+	return hex.EncodeToString(bytes), nil
 }
 
 // =============================================================================
@@ -431,13 +463,21 @@ func AutoSetupFromEnv() error {
 
 	// Generate JWT secret if not provided
 	if cfg.JWT.Secret == "" {
-		cfg.JWT.Secret = generateSecret(32)
+		secret, err := generateSecret(32)
+		if err != nil {
+			return fmt.Errorf("failed to generate jwt secret: %w", err)
+		}
+		cfg.JWT.Secret = secret
 		log.Println("Generated JWT secret automatically")
 	}
 
 	// Generate admin password if not provided
 	if cfg.Admin.Password == "" {
-		cfg.Admin.Password = generateSecret(16)
+		password, err := generateSecret(16)
+		if err != nil {
+			return fmt.Errorf("failed to generate admin password: %w", err)
+		}
+		cfg.Admin.Password = password
 		log.Printf("Generated admin password: %s", cfg.Admin.Password)
 		log.Println("IMPORTANT: Save this password! It will not be shown again.")
 	}

backend/internal/web/embed.go

@@ -41,7 +41,7 @@ func ServeEmbeddedFrontend() gin.HandlerFunc {
 		}
 
 		if file, err := distFS.Open(cleanPath); err == nil {
-			file.Close()
+			_ = file.Close()
 			fileServer.ServeHTTP(c.Writer, c.Request)
 			c.Abort()
 			return
@@ -59,7 +59,7 @@ func serveIndexHTML(c *gin.Context, fsys fs.FS) {
 		c.Abort()
 		return
 	}
-	defer file.Close()
+	defer func() { _ = file.Close() }()
 
 	content, err := io.ReadAll(file)
 	if err != nil {