fix(openai): 统一专属倍率计费链路并补齐回归测试

抽取共享的用户分组专属倍率解析器，统一缓存、singleflight 与回退逻辑。\n\n让 OpenAI 独立计费链路复用专属倍率解析，修复 usage 记录与实际扣费未命中用户专属倍率的问题。\n\n补齐 OpenAI 计费与解析器单元测试，并修复全量回归中暴露的 lint 阻塞项。\n\nCo-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

backend/cmd/server/wire_gen.go

@@ -164,7 +164,7 @@ func initializeApplication(buildInfo handler.BuildInfo) (*Application, error) {
 	digestSessionStore := service.NewDigestSessionStore()
 	gatewayService := service.NewGatewayService(accountRepository, groupRepository, usageLogRepository, userRepository, userSubscriptionRepository, userGroupRateRepository, gatewayCache, configConfig, schedulerSnapshotService, concurrencyService, billingService, rateLimitService, billingCacheService, identityService, httpUpstream, deferredService, claudeTokenProvider, sessionLimitCache, rpmCache, digestSessionStore)
 	openAITokenProvider := service.NewOpenAITokenProvider(accountRepository, geminiTokenCache, openAIOAuthService)
-	openAIGatewayService := service.NewOpenAIGatewayService(accountRepository, usageLogRepository, userRepository, userSubscriptionRepository, gatewayCache, configConfig, schedulerSnapshotService, concurrencyService, billingService, rateLimitService, billingCacheService, httpUpstream, deferredService, openAITokenProvider)
+	openAIGatewayService := service.NewOpenAIGatewayService(accountRepository, usageLogRepository, userRepository, userSubscriptionRepository, userGroupRateRepository, gatewayCache, configConfig, schedulerSnapshotService, concurrencyService, billingService, rateLimitService, billingCacheService, httpUpstream, deferredService, openAITokenProvider)
 	geminiMessagesCompatService := service.NewGeminiMessagesCompatService(accountRepository, groupRepository, gatewayCache, schedulerSnapshotService, geminiTokenProvider, rateLimitService, httpUpstream, antigravityGatewayService, configConfig)
 	opsSystemLogSink := service.ProvideOpsSystemLogSink(opsRepository)
 	opsService := service.NewOpsService(opsRepository, settingRepository, configConfig, accountRepository, userRepository, concurrencyService, gatewayService, openAIGatewayService, geminiMessagesCompatService, antigravityGatewayService, opsSystemLogSink)

backend/internal/service/gateway_service.go

@@ -501,33 +501,34 @@ func (s *GatewayService) TempUnscheduleRetryableError(ctx context.Context, accou
 
 // GatewayService handles API gateway operations
 type GatewayService struct {
-	accountRepo          AccountRepository
+	accountRepo           AccountRepository
-	groupRepo            GroupRepository
+	groupRepo             GroupRepository
-	usageLogRepo         UsageLogRepository
+	usageLogRepo          UsageLogRepository
-	userRepo             UserRepository
+	userRepo              UserRepository
-	userSubRepo          UserSubscriptionRepository
+	userSubRepo           UserSubscriptionRepository
-	userGroupRateRepo    UserGroupRateRepository
+	userGroupRateRepo     UserGroupRateRepository
-	cache                GatewayCache
+	cache                 GatewayCache
-	digestStore          *DigestSessionStore
+	digestStore           *DigestSessionStore
-	cfg                  *config.Config
+	cfg                   *config.Config
-	schedulerSnapshot    *SchedulerSnapshotService
+	schedulerSnapshot     *SchedulerSnapshotService
-	billingService       *BillingService
+	billingService        *BillingService
-	rateLimitService     *RateLimitService
+	rateLimitService      *RateLimitService
-	billingCacheService  *BillingCacheService
+	billingCacheService   *BillingCacheService
-	identityService      *IdentityService
+	identityService       *IdentityService
-	httpUpstream         HTTPUpstream
+	httpUpstream          HTTPUpstream
-	deferredService      *DeferredService
+	deferredService       *DeferredService
-	concurrencyService   *ConcurrencyService
+	concurrencyService    *ConcurrencyService
-	claudeTokenProvider  *ClaudeTokenProvider
+	claudeTokenProvider   *ClaudeTokenProvider
-	sessionLimitCache    SessionLimitCache // 会话数量限制缓存（仅 Anthropic OAuth/SetupToken）
+	sessionLimitCache     SessionLimitCache // 会话数量限制缓存（仅 Anthropic OAuth/SetupToken）
-	rpmCache             RPMCache          // RPM 计数缓存（仅 Anthropic OAuth/SetupToken）
+	rpmCache              RPMCache          // RPM 计数缓存（仅 Anthropic OAuth/SetupToken）
-	userGroupRateCache   *gocache.Cache
+	userGroupRateResolver *userGroupRateResolver
-	userGroupRateSF      singleflight.Group
+	userGroupRateCache    *gocache.Cache
-	modelsListCache      *gocache.Cache
+	userGroupRateSF       singleflight.Group
-	modelsListCacheTTL   time.Duration
+	modelsListCache       *gocache.Cache
-	responseHeaderFilter *responseheaders.CompiledHeaderFilter
+	modelsListCacheTTL    time.Duration
-	debugModelRouting    atomic.Bool
+	responseHeaderFilter  *responseheaders.CompiledHeaderFilter
-	debugClaudeMimic     atomic.Bool
+	debugModelRouting     atomic.Bool
+	debugClaudeMimic      atomic.Bool
 }
 
 // NewGatewayService creates a new GatewayService
@@ -582,6 +583,13 @@ func NewGatewayService(
 		modelsListCacheTTL:   modelsListTTL,
 		responseHeaderFilter: compileResponseHeaderFilter(cfg),
 	}
+	svc.userGroupRateResolver = newUserGroupRateResolver(
+		userGroupRateRepo,
+		svc.userGroupRateCache,
+		userGroupRateTTL,
+		&svc.userGroupRateSF,
+		"service.gateway",
+	)
 	svc.debugModelRouting.Store(parseDebugEnvBool(os.Getenv("SUB2API_DEBUG_MODEL_ROUTING")))
 	svc.debugClaudeMimic.Store(parseDebugEnvBool(os.Getenv("SUB2API_DEBUG_CLAUDE_MIMIC")))
 	return svc
@@ -6332,63 +6340,20 @@ func (s *GatewayService) replaceModelInResponseBody(body []byte, fromModel, toMo
 }
 
 func (s *GatewayService) getUserGroupRateMultiplier(ctx context.Context, userID, groupID int64, groupDefaultMultiplier float64) float64 {
-	if s == nil || userID <= 0 || groupID <= 0 {
+	if s == nil {
 		return groupDefaultMultiplier
 	}
-
+	resolver := s.userGroupRateResolver
-	key := fmt.Sprintf("%d:%d", userID, groupID)
+	if resolver == nil {
-	if s.userGroupRateCache != nil {
+		resolver = newUserGroupRateResolver(
-		if cached, ok := s.userGroupRateCache.Get(key); ok {
+			s.userGroupRateRepo,
-			if multiplier, castOK := cached.(float64); castOK {
+			s.userGroupRateCache,
-				userGroupRateCacheHitTotal.Add(1)
+			resolveUserGroupRateCacheTTL(s.cfg),
-				return multiplier
+			&s.userGroupRateSF,
-			}
+			"service.gateway",
-		}
+		)
 	}
-	if s.userGroupRateRepo == nil {
+	return resolver.Resolve(ctx, userID, groupID, groupDefaultMultiplier)
-		return groupDefaultMultiplier
-	}
-	userGroupRateCacheMissTotal.Add(1)
-
-	value, err, shared := s.userGroupRateSF.Do(key, func() (any, error) {
-		if s.userGroupRateCache != nil {
-			if cached, ok := s.userGroupRateCache.Get(key); ok {
-				if multiplier, castOK := cached.(float64); castOK {
-					userGroupRateCacheHitTotal.Add(1)
-					return multiplier, nil
-				}
-			}
-		}
-
-		userGroupRateCacheLoadTotal.Add(1)
-		userRate, repoErr := s.userGroupRateRepo.GetByUserAndGroup(ctx, userID, groupID)
-		if repoErr != nil {
-			return nil, repoErr
-		}
-		multiplier := groupDefaultMultiplier
-		if userRate != nil {
-			multiplier = *userRate
-		}
-		if s.userGroupRateCache != nil {
-			s.userGroupRateCache.Set(key, multiplier, resolveUserGroupRateCacheTTL(s.cfg))
-		}
-		return multiplier, nil
-	})
-	if shared {
-		userGroupRateCacheSFSharedTotal.Add(1)
-	}
-	if err != nil {
-		userGroupRateCacheFallbackTotal.Add(1)
-		logger.LegacyPrintf("service.gateway", "get user group rate failed, fallback to group default: user=%d group=%d err=%v", userID, groupID, err)
-		return groupDefaultMultiplier
-	}
-
-	multiplier, ok := value.(float64)
-	if !ok {
-		userGroupRateCacheFallbackTotal.Add(1)
-		return groupDefaultMultiplier
-	}
-	return multiplier
 }
 
 // RecordUsageInput 记录使用量的输入参数

backend/internal/service/openai_gateway_record_usage_test.go

@@ -0,0 +1,338 @@
+package service
+
+import (
+	"context"
+	"errors"
+	"testing"
+	"time"
+
+	"github.com/Wei-Shaw/sub2api/internal/config"
+	"github.com/stretchr/testify/require"
+)
+
+type openAIRecordUsageLogRepoStub struct {
+	UsageLogRepository
+
+	inserted bool
+	err      error
+	calls    int
+	lastLog  *UsageLog
+}
+
+func (s *openAIRecordUsageLogRepoStub) Create(ctx context.Context, log *UsageLog) (bool, error) {
+	s.calls++
+	s.lastLog = log
+	return s.inserted, s.err
+}
+
+type openAIRecordUsageUserRepoStub struct {
+	UserRepository
+
+	deductCalls int
+	deductErr   error
+	lastAmount  float64
+}
+
+func (s *openAIRecordUsageUserRepoStub) DeductBalance(ctx context.Context, id int64, amount float64) error {
+	s.deductCalls++
+	s.lastAmount = amount
+	return s.deductErr
+}
+
+type openAIRecordUsageSubRepoStub struct {
+	UserSubscriptionRepository
+
+	incrementCalls int
+	incrementErr   error
+	lastAmount     float64
+}
+
+func (s *openAIRecordUsageSubRepoStub) IncrementUsage(ctx context.Context, id int64, costUSD float64) error {
+	s.incrementCalls++
+	s.lastAmount = costUSD
+	return s.incrementErr
+}
+
+type openAIRecordUsageAPIKeyQuotaStub struct {
+	quotaCalls     int
+	rateLimitCalls int
+	err            error
+	lastAmount     float64
+}
+
+func (s *openAIRecordUsageAPIKeyQuotaStub) UpdateQuotaUsed(ctx context.Context, apiKeyID int64, cost float64) error {
+	s.quotaCalls++
+	s.lastAmount = cost
+	return s.err
+}
+
+func (s *openAIRecordUsageAPIKeyQuotaStub) UpdateRateLimitUsage(ctx context.Context, apiKeyID int64, cost float64) error {
+	s.rateLimitCalls++
+	s.lastAmount = cost
+	return s.err
+}
+
+type openAIUserGroupRateRepoStub struct {
+	UserGroupRateRepository
+
+	rate  *float64
+	err   error
+	calls int
+}
+
+func (s *openAIUserGroupRateRepoStub) GetByUserAndGroup(ctx context.Context, userID, groupID int64) (*float64, error) {
+	s.calls++
+	if s.err != nil {
+		return nil, s.err
+	}
+	return s.rate, nil
+}
+
+func i64p(v int64) *int64 {
+	return &v
+}
+
+func newOpenAIRecordUsageServiceForTest(usageRepo UsageLogRepository, userRepo UserRepository, subRepo UserSubscriptionRepository, rateRepo UserGroupRateRepository) *OpenAIGatewayService {
+	cfg := &config.Config{}
+	cfg.Default.RateMultiplier = 1.1
+
+	return &OpenAIGatewayService{
+		usageLogRepo:        usageRepo,
+		userRepo:            userRepo,
+		userSubRepo:         subRepo,
+		cfg:                 cfg,
+		billingService:      NewBillingService(cfg, nil),
+		billingCacheService: &BillingCacheService{},
+		deferredService:     &DeferredService{},
+		userGroupRateResolver: newUserGroupRateResolver(
+			rateRepo,
+			nil,
+			resolveUserGroupRateCacheTTL(cfg),
+			nil,
+			"service.openai_gateway.test",
+		),
+	}
+}
+
+func expectedOpenAICost(t *testing.T, svc *OpenAIGatewayService, model string, usage OpenAIUsage, multiplier float64) *CostBreakdown {
+	t.Helper()
+
+	cost, err := svc.billingService.CalculateCost(model, UsageTokens{
+		InputTokens:         max(usage.InputTokens-usage.CacheReadInputTokens, 0),
+		OutputTokens:        usage.OutputTokens,
+		CacheCreationTokens: usage.CacheCreationInputTokens,
+		CacheReadTokens:     usage.CacheReadInputTokens,
+	}, multiplier)
+	require.NoError(t, err)
+	return cost
+}
+
+func max(a, b int) int {
+	if a > b {
+		return a
+	}
+	return b
+}
+
+func TestOpenAIGatewayServiceRecordUsage_UsesUserSpecificGroupRate(t *testing.T) {
+	groupID := int64(11)
+	groupRate := 1.4
+	userRate := 1.8
+	usage := OpenAIUsage{InputTokens: 15, OutputTokens: 4, CacheReadInputTokens: 3}
+
+	usageRepo := &openAIRecordUsageLogRepoStub{inserted: true}
+	userRepo := &openAIRecordUsageUserRepoStub{}
+	subRepo := &openAIRecordUsageSubRepoStub{}
+	rateRepo := &openAIUserGroupRateRepoStub{rate: &userRate}
+	svc := newOpenAIRecordUsageServiceForTest(usageRepo, userRepo, subRepo, rateRepo)
+
+	err := svc.RecordUsage(context.Background(), &OpenAIRecordUsageInput{
+		Result: &OpenAIForwardResult{
+			RequestID: "resp_user_group_rate",
+			Usage:     usage,
+			Model:     "gpt-5.1",
+			Duration:  time.Second,
+		},
+		APIKey: &APIKey{
+			ID:      1001,
+			GroupID: i64p(groupID),
+			Group: &Group{
+				ID:             groupID,
+				RateMultiplier: groupRate,
+			},
+		},
+		User:    &User{ID: 2001},
+		Account: &Account{ID: 3001},
+	})
+
+	require.NoError(t, err)
+	require.Equal(t, 1, rateRepo.calls)
+	require.NotNil(t, usageRepo.lastLog)
+	require.Equal(t, userRate, usageRepo.lastLog.RateMultiplier)
+	require.Equal(t, 12, usageRepo.lastLog.InputTokens)
+	require.Equal(t, 3, usageRepo.lastLog.CacheReadTokens)
+
+	expected := expectedOpenAICost(t, svc, "gpt-5.1", usage, userRate)
+	require.InDelta(t, expected.ActualCost, usageRepo.lastLog.ActualCost, 1e-12)
+	require.InDelta(t, expected.ActualCost, userRepo.lastAmount, 1e-12)
+	require.Equal(t, 1, userRepo.deductCalls)
+}
+
+func TestOpenAIGatewayServiceRecordUsage_FallsBackToGroupDefaultRateOnResolverError(t *testing.T) {
+	groupID := int64(12)
+	groupRate := 1.6
+	usage := OpenAIUsage{InputTokens: 10, OutputTokens: 5, CacheReadInputTokens: 2}
+
+	usageRepo := &openAIRecordUsageLogRepoStub{inserted: true}
+	userRepo := &openAIRecordUsageUserRepoStub{}
+	subRepo := &openAIRecordUsageSubRepoStub{}
+	rateRepo := &openAIUserGroupRateRepoStub{err: errors.New("db unavailable")}
+	svc := newOpenAIRecordUsageServiceForTest(usageRepo, userRepo, subRepo, rateRepo)
+
+	err := svc.RecordUsage(context.Background(), &OpenAIRecordUsageInput{
+		Result: &OpenAIForwardResult{
+			RequestID: "resp_group_default_on_error",
+			Usage:     usage,
+			Model:     "gpt-5.1",
+			Duration:  time.Second,
+		},
+		APIKey: &APIKey{
+			ID:      1002,
+			GroupID: i64p(groupID),
+			Group: &Group{
+				ID:             groupID,
+				RateMultiplier: groupRate,
+			},
+		},
+		User:    &User{ID: 2002},
+		Account: &Account{ID: 3002},
+	})
+
+	require.NoError(t, err)
+	require.Equal(t, 1, rateRepo.calls)
+	require.NotNil(t, usageRepo.lastLog)
+	require.Equal(t, groupRate, usageRepo.lastLog.RateMultiplier)
+
+	expected := expectedOpenAICost(t, svc, "gpt-5.1", usage, groupRate)
+	require.InDelta(t, expected.ActualCost, userRepo.lastAmount, 1e-12)
+}
+
+func TestOpenAIGatewayServiceRecordUsage_FallsBackToGroupDefaultRateWhenResolverMissing(t *testing.T) {
+	groupID := int64(13)
+	groupRate := 1.25
+	usage := OpenAIUsage{InputTokens: 9, OutputTokens: 4, CacheReadInputTokens: 1}
+
+	usageRepo := &openAIRecordUsageLogRepoStub{inserted: true}
+	userRepo := &openAIRecordUsageUserRepoStub{}
+	subRepo := &openAIRecordUsageSubRepoStub{}
+	svc := newOpenAIRecordUsageServiceForTest(usageRepo, userRepo, subRepo, nil)
+	svc.userGroupRateResolver = nil
+
+	err := svc.RecordUsage(context.Background(), &OpenAIRecordUsageInput{
+		Result: &OpenAIForwardResult{
+			RequestID: "resp_group_default_nil_resolver",
+			Usage:     usage,
+			Model:     "gpt-5.1",
+			Duration:  time.Second,
+		},
+		APIKey: &APIKey{
+			ID:      1003,
+			GroupID: i64p(groupID),
+			Group: &Group{
+				ID:             groupID,
+				RateMultiplier: groupRate,
+			},
+		},
+		User:    &User{ID: 2003},
+		Account: &Account{ID: 3003},
+	})
+
+	require.NoError(t, err)
+	require.NotNil(t, usageRepo.lastLog)
+	require.Equal(t, groupRate, usageRepo.lastLog.RateMultiplier)
+}
+
+func TestOpenAIGatewayServiceRecordUsage_DuplicateUsageLogSkipsBilling(t *testing.T) {
+	usageRepo := &openAIRecordUsageLogRepoStub{inserted: false}
+	userRepo := &openAIRecordUsageUserRepoStub{}
+	subRepo := &openAIRecordUsageSubRepoStub{}
+	svc := newOpenAIRecordUsageServiceForTest(usageRepo, userRepo, subRepo, nil)
+
+	err := svc.RecordUsage(context.Background(), &OpenAIRecordUsageInput{
+		Result: &OpenAIForwardResult{
+			RequestID: "resp_duplicate",
+			Usage: OpenAIUsage{
+				InputTokens:  8,
+				OutputTokens: 4,
+			},
+			Model:    "gpt-5.1",
+			Duration: time.Second,
+		},
+		APIKey:  &APIKey{ID: 1004},
+		User:    &User{ID: 2004},
+		Account: &Account{ID: 3004},
+	})
+
+	require.NoError(t, err)
+	require.Equal(t, 1, usageRepo.calls)
+	require.Equal(t, 0, userRepo.deductCalls)
+	require.Equal(t, 0, subRepo.incrementCalls)
+}
+
+func TestOpenAIGatewayServiceRecordUsage_UpdatesAPIKeyQuotaWhenConfigured(t *testing.T) {
+	usage := OpenAIUsage{InputTokens: 10, OutputTokens: 6, CacheReadInputTokens: 2}
+	usageRepo := &openAIRecordUsageLogRepoStub{inserted: true}
+	userRepo := &openAIRecordUsageUserRepoStub{}
+	subRepo := &openAIRecordUsageSubRepoStub{}
+	quotaSvc := &openAIRecordUsageAPIKeyQuotaStub{}
+	svc := newOpenAIRecordUsageServiceForTest(usageRepo, userRepo, subRepo, nil)
+
+	err := svc.RecordUsage(context.Background(), &OpenAIRecordUsageInput{
+		Result: &OpenAIForwardResult{
+			RequestID: "resp_quota_update",
+			Usage:     usage,
+			Model:     "gpt-5.1",
+			Duration:  time.Second,
+		},
+		APIKey: &APIKey{
+			ID:    1005,
+			Quota: 100,
+		},
+		User:          &User{ID: 2005},
+		Account:       &Account{ID: 3005},
+		APIKeyService: quotaSvc,
+	})
+
+	require.NoError(t, err)
+	require.Equal(t, 1, quotaSvc.quotaCalls)
+	require.Equal(t, 0, quotaSvc.rateLimitCalls)
+	expected := expectedOpenAICost(t, svc, "gpt-5.1", usage, 1.1)
+	require.InDelta(t, expected.ActualCost, quotaSvc.lastAmount, 1e-12)
+}
+
+func TestOpenAIGatewayServiceRecordUsage_ClampsActualInputTokensToZero(t *testing.T) {
+	usageRepo := &openAIRecordUsageLogRepoStub{inserted: true}
+	userRepo := &openAIRecordUsageUserRepoStub{}
+	subRepo := &openAIRecordUsageSubRepoStub{}
+	svc := newOpenAIRecordUsageServiceForTest(usageRepo, userRepo, subRepo, nil)
+
+	err := svc.RecordUsage(context.Background(), &OpenAIRecordUsageInput{
+		Result: &OpenAIForwardResult{
+			RequestID: "resp_clamp_actual_input",
+			Usage: OpenAIUsage{
+				InputTokens:          2,
+				OutputTokens:         1,
+				CacheReadInputTokens: 5,
+			},
+			Model:    "gpt-5.1",
+			Duration: time.Second,
+		},
+		APIKey:  &APIKey{ID: 1006},
+		User:    &User{ID: 2006},
+		Account: &Account{ID: 3006},
+	})
+
+	require.NoError(t, err)
+	require.NotNil(t, usageRepo.lastLog)
+	require.Equal(t, 0, usageRepo.lastLog.InputTokens)
+}

backend/internal/service/openai_gateway_service.go

@@ -245,23 +245,24 @@ type openAIWSRetryMetrics struct {
 
 // OpenAIGatewayService handles OpenAI API gateway operations
 type OpenAIGatewayService struct {
-	accountRepo         AccountRepository
+	accountRepo           AccountRepository
-	usageLogRepo        UsageLogRepository
+	usageLogRepo          UsageLogRepository
-	userRepo            UserRepository
+	userRepo              UserRepository
-	userSubRepo         UserSubscriptionRepository
+	userSubRepo           UserSubscriptionRepository
-	cache               GatewayCache
+	cache                 GatewayCache
-	cfg                 *config.Config
+	cfg                   *config.Config
-	codexDetector       CodexClientRestrictionDetector
+	codexDetector         CodexClientRestrictionDetector
-	schedulerSnapshot   *SchedulerSnapshotService
+	schedulerSnapshot     *SchedulerSnapshotService
-	concurrencyService  *ConcurrencyService
+	concurrencyService    *ConcurrencyService
-	billingService      *BillingService
+	billingService        *BillingService
-	rateLimitService    *RateLimitService
+	rateLimitService      *RateLimitService
-	billingCacheService *BillingCacheService
+	billingCacheService   *BillingCacheService
-	httpUpstream        HTTPUpstream
+	userGroupRateResolver *userGroupRateResolver
-	deferredService     *DeferredService
+	httpUpstream          HTTPUpstream
-	openAITokenProvider *OpenAITokenProvider
+	deferredService       *DeferredService
-	toolCorrector       *CodexToolCorrector
+	openAITokenProvider   *OpenAITokenProvider
-	openaiWSResolver    OpenAIWSProtocolResolver
+	toolCorrector         *CodexToolCorrector
+	openaiWSResolver      OpenAIWSProtocolResolver
 
 	openaiWSPoolOnce              sync.Once
 	openaiWSStateStoreOnce        sync.Once
@@ -284,6 +285,7 @@ func NewOpenAIGatewayService(
 	usageLogRepo UsageLogRepository,
 	userRepo UserRepository,
 	userSubRepo UserSubscriptionRepository,
+	userGroupRateRepo UserGroupRateRepository,
 	cache GatewayCache,
 	cfg *config.Config,
 	schedulerSnapshot *SchedulerSnapshotService,
@@ -296,18 +298,25 @@ func NewOpenAIGatewayService(
 	openAITokenProvider *OpenAITokenProvider,
 ) *OpenAIGatewayService {
 	svc := &OpenAIGatewayService{
-		accountRepo:          accountRepo,
+		accountRepo:         accountRepo,
-		usageLogRepo:         usageLogRepo,
+		usageLogRepo:        usageLogRepo,
-		userRepo:             userRepo,
+		userRepo:            userRepo,
-		userSubRepo:          userSubRepo,
+		userSubRepo:         userSubRepo,
-		cache:                cache,
+		cache:               cache,
-		cfg:                  cfg,
+		cfg:                 cfg,
-		codexDetector:        NewOpenAICodexClientRestrictionDetector(cfg),
+		codexDetector:       NewOpenAICodexClientRestrictionDetector(cfg),
-		schedulerSnapshot:    schedulerSnapshot,
+		schedulerSnapshot:   schedulerSnapshot,
-		concurrencyService:   concurrencyService,
+		concurrencyService:  concurrencyService,
-		billingService:       billingService,
+		billingService:      billingService,
-		rateLimitService:     rateLimitService,
+		rateLimitService:    rateLimitService,
-		billingCacheService:  billingCacheService,
+		billingCacheService: billingCacheService,
+		userGroupRateResolver: newUserGroupRateResolver(
+			userGroupRateRepo,
+			nil,
+			resolveUserGroupRateCacheTTL(cfg),
+			nil,
+			"service.openai_gateway",
+		),
 		httpUpstream:         httpUpstream,
 		deferredService:      deferredService,
 		openAITokenProvider:  openAITokenProvider,
@@ -3261,6 +3270,14 @@ func (s *OpenAIGatewayService) handleOAuthSSEToJSON(resp *http.Response, c *gin.
 		// Correct tool calls in final response
 		body = s.correctToolCallsInResponseBody(body)
 	} else {
+		terminalType, terminalPayload, terminalOK := extractOpenAISSETerminalEvent(bodyText)
+		if terminalOK && terminalType == "response.failed" {
+			msg := extractOpenAISSEErrorMessage(terminalPayload)
+			if msg == "" {
+				msg = "Upstream compact response failed"
+			}
+			return nil, s.writeOpenAINonStreamingProtocolError(resp, c, msg)
+		}
 		usage = s.parseSSEUsageFromBody(bodyText)
 		if originalModel != mappedModel {
 			bodyText = s.replaceModelInSSEBody(bodyText, mappedModel, originalModel)
@@ -3282,6 +3299,51 @@ func (s *OpenAIGatewayService) handleOAuthSSEToJSON(resp *http.Response, c *gin.
 	return usage, nil
 }
 
+func extractOpenAISSETerminalEvent(body string) (string, []byte, bool) {
+	lines := strings.Split(body, "\n")
+	for _, line := range lines {
+		data, ok := extractOpenAISSEDataLine(line)
+		if !ok || data == "" || data == "[DONE]" {
+			continue
+		}
+		eventType := strings.TrimSpace(gjson.Get(data, "type").String())
+		switch eventType {
+		case "response.completed", "response.done", "response.failed":
+			return eventType, []byte(data), true
+		}
+	}
+	return "", nil, false
+}
+
+func extractOpenAISSEErrorMessage(payload []byte) string {
+	if len(payload) == 0 {
+		return ""
+	}
+	for _, path := range []string{"response.error.message", "error.message", "message"} {
+		if msg := strings.TrimSpace(gjson.GetBytes(payload, path).String()); msg != "" {
+			return sanitizeUpstreamErrorMessage(msg)
+		}
+	}
+	return sanitizeUpstreamErrorMessage(strings.TrimSpace(extractUpstreamErrorMessage(payload)))
+}
+
+func (s *OpenAIGatewayService) writeOpenAINonStreamingProtocolError(resp *http.Response, c *gin.Context, message string) error {
+	message = sanitizeUpstreamErrorMessage(strings.TrimSpace(message))
+	if message == "" {
+		message = "Upstream returned an invalid non-streaming response"
+	}
+	setOpsUpstreamError(c, http.StatusBadGateway, message, "")
+	responseheaders.WriteFilteredHeaders(c.Writer.Header(), resp.Header, s.responseHeaderFilter)
+	c.Writer.Header().Set("Content-Type", "application/json; charset=utf-8")
+	c.JSON(http.StatusBadGateway, gin.H{
+		"error": gin.H{
+			"type":    "upstream_error",
+			"message": message,
+		},
+	})
+	return fmt.Errorf("non-streaming openai protocol error: %s", message)
+}
+
 func extractCodexFinalResponse(body string) ([]byte, bool) {
 	lines := strings.Split(body, "\n")
 	for _, line := range lines {
@@ -3413,7 +3475,11 @@ func (s *OpenAIGatewayService) RecordUsage(ctx context.Context, input *OpenAIRec
 	// Get rate multiplier
 	multiplier := s.cfg.Default.RateMultiplier
 	if apiKey.GroupID != nil && apiKey.Group != nil {
-		multiplier = apiKey.Group.RateMultiplier
+		resolver := s.userGroupRateResolver
+		if resolver == nil {
+			resolver = newUserGroupRateResolver(nil, nil, resolveUserGroupRateCacheTTL(s.cfg), nil, "service.openai_gateway")
+		}
+		multiplier = resolver.Resolve(ctx, user.ID, *apiKey.GroupID, apiKey.Group.RateMultiplier)
 	}
 
 	cost, err := s.billingService.CalculateCost(result.Model, tokens, multiplier)

backend/internal/service/openai_gateway_service_test.go

@@ -1576,3 +1576,27 @@ func TestHandleOAuthSSEToJSON_NoFinalResponseKeepsSSEBody(t *testing.T) {
 	require.Contains(t, rec.Header().Get("Content-Type"), "text/event-stream")
 	require.Contains(t, rec.Body.String(), `data: {"type":"response.in_progress"`)
 }
+
+func TestHandleOAuthSSEToJSON_ResponseFailedReturnsProtocolError(t *testing.T) {
+	gin.SetMode(gin.TestMode)
+	rec := httptest.NewRecorder()
+	c, _ := gin.CreateTestContext(rec)
+	c.Request = httptest.NewRequest(http.MethodPost, "/", nil)
+
+	svc := &OpenAIGatewayService{cfg: &config.Config{}}
+	resp := &http.Response{
+		StatusCode: http.StatusOK,
+		Header:     http.Header{"Content-Type": []string{"text/event-stream"}},
+	}
+	body := []byte(strings.Join([]string{
+		`data: {"type":"response.failed","error":{"message":"upstream rejected request"}}`,
+		`data: [DONE]`,
+	}, "\n"))
+
+	usage, err := svc.handleOAuthSSEToJSON(resp, c, body, "gpt-4o", "gpt-4o")
+	require.Nil(t, usage)
+	require.Error(t, err)
+	require.Equal(t, http.StatusBadGateway, rec.Code)
+	require.Contains(t, rec.Body.String(), "upstream rejected request")
+	require.Contains(t, rec.Header().Get("Content-Type"), "application/json")
+}

backend/internal/service/openai_ws_protocol_forward_test.go

@@ -391,6 +391,7 @@ func TestNewOpenAIGatewayService_InitializesOpenAIWSResolver(t *testing.T) {
 		nil,
 		nil,
 		nil,
+		nil,
 		cfg,
 		nil,
 		nil,

backend/internal/service/user_group_rate_resolver.go

@@ -0,0 +1,103 @@
+package service
+
+import (
+	"context"
+	"fmt"
+	"time"
+
+	"github.com/Wei-Shaw/sub2api/internal/pkg/logger"
+	gocache "github.com/patrickmn/go-cache"
+	"golang.org/x/sync/singleflight"
+)
+
+type userGroupRateResolver struct {
+	repo         UserGroupRateRepository
+	cache        *gocache.Cache
+	cacheTTL     time.Duration
+	sf           *singleflight.Group
+	logComponent string
+}
+
+func newUserGroupRateResolver(repo UserGroupRateRepository, cache *gocache.Cache, cacheTTL time.Duration, sf *singleflight.Group, logComponent string) *userGroupRateResolver {
+	if cacheTTL <= 0 {
+		cacheTTL = defaultUserGroupRateCacheTTL
+	}
+	if cache == nil {
+		cache = gocache.New(cacheTTL, time.Minute)
+	}
+	if logComponent == "" {
+		logComponent = "service.gateway"
+	}
+	if sf == nil {
+		sf = &singleflight.Group{}
+	}
+
+	return &userGroupRateResolver{
+		repo:         repo,
+		cache:        cache,
+		cacheTTL:     cacheTTL,
+		sf:           sf,
+		logComponent: logComponent,
+	}
+}
+
+func (r *userGroupRateResolver) Resolve(ctx context.Context, userID, groupID int64, groupDefaultMultiplier float64) float64 {
+	if r == nil || userID <= 0 || groupID <= 0 {
+		return groupDefaultMultiplier
+	}
+
+	key := fmt.Sprintf("%d:%d", userID, groupID)
+	if r.cache != nil {
+		if cached, ok := r.cache.Get(key); ok {
+			if multiplier, castOK := cached.(float64); castOK {
+				userGroupRateCacheHitTotal.Add(1)
+				return multiplier
+			}
+		}
+	}
+	if r.repo == nil {
+		return groupDefaultMultiplier
+	}
+	userGroupRateCacheMissTotal.Add(1)
+
+	value, err, shared := r.sf.Do(key, func() (any, error) {
+		if r.cache != nil {
+			if cached, ok := r.cache.Get(key); ok {
+				if multiplier, castOK := cached.(float64); castOK {
+					userGroupRateCacheHitTotal.Add(1)
+					return multiplier, nil
+				}
+			}
+		}
+
+		userGroupRateCacheLoadTotal.Add(1)
+		userRate, repoErr := r.repo.GetByUserAndGroup(ctx, userID, groupID)
+		if repoErr != nil {
+			return nil, repoErr
+		}
+
+		multiplier := groupDefaultMultiplier
+		if userRate != nil {
+			multiplier = *userRate
+		}
+		if r.cache != nil {
+			r.cache.Set(key, multiplier, r.cacheTTL)
+		}
+		return multiplier, nil
+	})
+	if shared {
+		userGroupRateCacheSFSharedTotal.Add(1)
+	}
+	if err != nil {
+		userGroupRateCacheFallbackTotal.Add(1)
+		logger.LegacyPrintf(r.logComponent, "get user group rate failed, fallback to group default: user=%d group=%d err=%v", userID, groupID, err)
+		return groupDefaultMultiplier
+	}
+
+	multiplier, ok := value.(float64)
+	if !ok {
+		userGroupRateCacheFallbackTotal.Add(1)
+		return groupDefaultMultiplier
+	}
+	return multiplier
+}

backend/internal/service/user_group_rate_resolver_test.go

@@ -0,0 +1,83 @@
+package service
+
+import (
+	"context"
+	"testing"
+	"time"
+
+	gocache "github.com/patrickmn/go-cache"
+	"github.com/stretchr/testify/require"
+)
+
+type userGroupRateResolverRepoStub struct {
+	UserGroupRateRepository
+
+	rate  *float64
+	err   error
+	calls int
+}
+
+func (s *userGroupRateResolverRepoStub) GetByUserAndGroup(ctx context.Context, userID, groupID int64) (*float64, error) {
+	s.calls++
+	if s.err != nil {
+		return nil, s.err
+	}
+	return s.rate, nil
+}
+
+func TestNewUserGroupRateResolver_Defaults(t *testing.T) {
+	resolver := newUserGroupRateResolver(nil, nil, 0, nil, "")
+
+	require.NotNil(t, resolver)
+	require.NotNil(t, resolver.cache)
+	require.Equal(t, defaultUserGroupRateCacheTTL, resolver.cacheTTL)
+	require.NotNil(t, resolver.sf)
+	require.Equal(t, "service.gateway", resolver.logComponent)
+}
+
+func TestUserGroupRateResolverResolve_FallbackForNilResolverAndInvalidIDs(t *testing.T) {
+	var nilResolver *userGroupRateResolver
+	require.Equal(t, 1.4, nilResolver.Resolve(context.Background(), 101, 202, 1.4))
+
+	resolver := newUserGroupRateResolver(nil, nil, time.Second, nil, "service.test")
+	require.Equal(t, 1.4, resolver.Resolve(context.Background(), 0, 202, 1.4))
+	require.Equal(t, 1.4, resolver.Resolve(context.Background(), 101, 0, 1.4))
+}
+
+func TestUserGroupRateResolverResolve_InvalidCacheEntryLoadsRepoAndCaches(t *testing.T) {
+	resetGatewayHotpathStatsForTest()
+
+	rate := 1.7
+	repo := &userGroupRateResolverRepoStub{rate: &rate}
+	cache := gocache.New(time.Minute, time.Minute)
+	cache.Set("101:202", "bad-cache", time.Minute)
+	resolver := newUserGroupRateResolver(repo, cache, time.Minute, nil, "service.test")
+
+	got := resolver.Resolve(context.Background(), 101, 202, 1.2)
+	require.Equal(t, rate, got)
+	require.Equal(t, 1, repo.calls)
+
+	cached, ok := cache.Get("101:202")
+	require.True(t, ok)
+	require.Equal(t, rate, cached)
+
+	hit, miss, load, _, fallback := GatewayUserGroupRateCacheStats()
+	require.Equal(t, int64(0), hit)
+	require.Equal(t, int64(1), miss)
+	require.Equal(t, int64(1), load)
+	require.Equal(t, int64(0), fallback)
+}
+
+func TestGatewayServiceGetUserGroupRateMultiplier_FallbacksAndUsesExistingResolver(t *testing.T) {
+	var nilSvc *GatewayService
+	require.Equal(t, 1.3, nilSvc.getUserGroupRateMultiplier(context.Background(), 101, 202, 1.3))
+
+	rate := 1.9
+	repo := &userGroupRateResolverRepoStub{rate: &rate}
+	resolver := newUserGroupRateResolver(repo, nil, time.Minute, nil, "service.gateway")
+	svc := &GatewayService{userGroupRateResolver: resolver}
+
+	got := svc.getUserGroupRateMultiplier(context.Background(), 101, 202, 1.2)
+	require.Equal(t, rate, got)
+	require.Equal(t, 1, repo.calls)
+}