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/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 {